Agronomy

Article

16 pages, 58236 KiB

Open AccessEditor’s ChoiceArticle

Fabrication of Copper Oxide Nanoparticles Using Passiflora edulis Extract for the Estimation of Antioxidant Potential and Photocatalytic Methylene Blue Dye Degradation

by Amina Yasin, Urooj Fatima, Sammia Shahid, Sana Mansoor, Hina Inam, Mohsin Javed, Shahid Iqbal, Hamad Alrbyawi, Hamoud H. Somaily, Rami Adel Pashameah, Eman Alzahrani and Abd-ElAziem Farouk

Agronomy 2022, 12(10), 2315; https://doi.org/10.3390/agronomy12102315 - 27 Sep 2022

Cited by 31 | Viewed by 6380

Abstract

In the present work, copper oxide nanoparticles have been fabricated by using a biological method. Copper oxide nanoparticles (CuO NPs) have received more attention than other metal oxides due to their distinctive properties and applications. Plant-mediated synthesis of nanoparticles has gained the attention [...] Read more.

In the present work, copper oxide nanoparticles have been fabricated by using a biological method. Copper oxide nanoparticles (CuO NPs) have received more attention than other metal oxides due to their distinctive properties and applications. Plant-mediated synthesis of nanoparticles has gained the attention of researchers because of its simple and ecologically sustainable approach. The biosynthesis of CuO NPs included the use of Passiflora edulis leaf extract that acts as a stabilizing and reducing agent. A non-toxic, cost-effective, and ecologically acceptable method was the use of plant leaf extract in the biogenesis of nanoscale materials. UV-vis, SEM, FTIR, and XRD techniques were used to examine the biologically produced copper oxide nanoparticles. The findings of the SEM examination, which gives morphological information, demonstrate that the synthesized NPs have a spherical shape and have an average particle size of between 60 and 65 nm. CuO has been further investigated in the current study as a photo-catalyst in the methylene blue (MB) dye degradation and as an antioxidant in free radical scavenging activities. The decolorization efficiency was approximately 93% after 160 min. Furthermore, CuO nanoparticles were tested for antioxidant performance by scavenging 2, 2-diphenyl-1-picrylhydrazyl hydrate free radicals (DPPH) and evaluated by UV-Vis spectroscopy. The result showed that biologically synthesized CuO NPs can be used as an effective antioxidant. The half maximal inhibitory concentration IC50 of copper oxide nanoparticles was found to be in the range of 0.13–0.20. Full article

(This article belongs to the Special Issue Phytochemicals of Edible Plants—Volume II)

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13 pages, 2547 KiB

Open AccessEditor’s ChoiceCommunication

Nitrous Oxide Emission and Grain Yield in Chinese Winter Wheat–Summer Maize Rotation: A Meta-Analysis

by Chengcheng Yao, Xiongwei Wu, He Bai and Jiangxin Gu

Agronomy 2022, 12(10), 2305; https://doi.org/10.3390/agronomy12102305 - 26 Sep 2022

Cited by 6 | Viewed by 3598

Abstract

A systematic understanding of nitrous oxide (N₂O) emission and grain yield in winter wheat–summer maize rotation, one of the most important cereal cropping systems in China, is still lacking. The primary aim of this study was to quantify the N₂ [...] Read more.

A systematic understanding of nitrous oxide (N₂O) emission and grain yield in winter wheat–summer maize rotation, one of the most important cereal cropping systems in China, is still lacking. The primary aim of this study was to quantify the N₂O emissions and grain yield, as well as responses to mitigation strategies, in this intensively managed agroecosystem. We conducted a pairwise meta-analysis by compiling a comprehensive dataset of annual N₂O emissions (n = 530) and grain yields (n = 352) from peer−reviewed publications. The N₂O emissions increased with nitrogen (N) fertilizer input rates following a linear model (r² = 0.295, p < 0.001), giving a specific emission coefficient and background emission of 0.71% and 0.5 kg N ha⁻¹ yr⁻¹, respectively. The grain yields responded to the N input rates following a linear-plateau model (r² = 0.478, p < 0.001), giving an optimal N input rate and maximum grain yield of 405 kg N ha⁻¹ yr⁻¹ and 15.5 t ha⁻¹ yr⁻¹, respectively. The meta-analyses revealed that reducing N fertilizers (approximately 50% of the full N input), water-saving irrigation, reduced or no tillage, and applying enhanced efficiency fertilizers significantly decreased N₂O emissions (range: −45% to −9%) and increased or did not impact grain yields (range: −1% to 3%). We recommend that reducing agricultural inputs (i.e., N fertilizers, irrigation, and tillage) is a feasible N₂O mitigation strategy in the intensively managed winter wheat–summer maize rotation that can be employed without additional environmental risks. Full article

(This article belongs to the Special Issue Effects of Tillage, Cover Crop and Crop Rotation on Soil)

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15 pages, 2177 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Rotational Cropping of Industrial Hemp (Cannabis sativa L.) on Rhizosphere Soil Microbial Communities

by Lili Tang, Chao Fan, Hongmei Yuan, Guangwen Wu, Jing Sun and Shuquan Zhang

Agronomy 2022, 12(10), 2293; https://doi.org/10.3390/agronomy12102293 - 24 Sep 2022

Cited by 6 | Viewed by 4950

Abstract

Crop rotation affects soil properties and soil microbial diversity and structure. Currently, it is not well understood how soil microbial diversity changes following different crop rotation systems of industrial hemp, an ancient and economically important crop. Therefore, these changes were analyzed in this [...] Read more.

Crop rotation affects soil properties and soil microbial diversity and structure. Currently, it is not well understood how soil microbial diversity changes following different crop rotation systems of industrial hemp, an ancient and economically important crop. Therefore, these changes were analyzed in this study. Our results showed that different rotation systems significantly affected the wilt disease incidence, plant height, yield, soil physicochemical properties and soil microbial communities in the greenhouse. The rotation systems used in this study significantly reduced the plant mortality and increased the yield compared with a monoculture system. The levels of alkaline hydrolysis and available phosphorus in the soil decreased significantly compared with a monoculture cropping system. Using MiSeq high-throughput sequencing, we showed that the soil diversity and number of bacteria and fungi were significantly higher for rotation systems and controls compared to the monoculture system. The relative abundance of pathogens increased with a monoculture system. Redundancy analysis suggests that soil properties may also affect the soil microbial composition. Taken together, different rotation systems used in this study significantly decreased the disease incidence, increased plant yields and increased soil microbial diversity compared with monoculture for industrial hemp. We believe that applying these rotation systems is an efficient and eco-friendly approach to control soil borne pathogenic diseases and increase floral yields. Full article

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20 pages, 1912 KiB

Open AccessEditor’s ChoiceArticle

Salinity Effect on Plant Growth Parameters and Fruit Bioactive Compounds of Two Strawberry Cultivars, Coupled with Environmental Conditions Monitoring

by Nikoleta-Kleio Denaxa, Aggeliki Nomikou, Nikolaos Malamos, Eleni Liveri, Petros Anargyrou Roussos and Vasileios Papasotiropoulos

Agronomy 2022, 12(10), 2279; https://doi.org/10.3390/agronomy12102279 - 23 Sep 2022

Cited by 29 | Viewed by 4671

Abstract

Salinity stress is one of the most vital abiotic stresses, impairing the productivity of crops in both irrigated and dry areas. A pot experiment was carried out in a greenhouse environment, aiming to examine the relevant tolerances and evaluate the effect of salinity [...] Read more.

Salinity stress is one of the most vital abiotic stresses, impairing the productivity of crops in both irrigated and dry areas. A pot experiment was carried out in a greenhouse environment, aiming to examine the relevant tolerances and evaluate the effect of salinity stress on plant growth, fruit physiological, and quality traits of two strawberry cultivars, Camarosa and Rociera. The plants were irrigated with water with electrical conductivity (EC) of 0.4 dS m⁻¹ (control), or with a salt solution with either ECs 2 dS m⁻¹ (moderate salt stress) or 4 dS m⁻¹ (elevated salt stress). Furthermore, several meteorological parameters, as well as soil moisture, were monitored inside the greenhouse. The results showed that salinity induced osmotic stress, water deprivation, and toxic effects, affecting the growth parameters and yield of both cultivars. The elevated salt stress imposed a negative impact on Rociera’s fruits carbohydrates, organic acids, and anthocyanins, while the antioxidant capacity increased. However, Rociera exhibited high total yield/plant and total yield even under elevated salt stress compared to Camarosa. Camarosa plants grown under high salt levels presented low salinity tolerance index, plant water content, and growth parameters. The fruits exhibited low fresh weight but high sweetness index and antioxidant power. An accumulation of soluble sugars under saline conditions, especially sucrose, was also detected in cv. Camarosa fruits when compared to Rociera. Therefore, the two cvs. exhibited a different pattern of response to salinity stress concerning their physiological, biochemical and nutritional characteristics; however, either could be an interesting alternative for cultivation in areas where a slight salinization of the water or soil imposes a limitation on the rather salt-sensitive crops. Agronomic and biochemical evaluation of salinity stress coupled with monitoring of greenhouse microclimatic conditions will lead to a better understanding of the effects on plant growth and quality characteristics, enhancing the productivity of strawberry cultivars, especially under salt-affected environments. Full article

(This article belongs to the Special Issue Toward a "Green Revolution" for Crop Breeding)

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13 pages, 2224 KiB

Open AccessEditor’s ChoiceArticle

Genotype Selection, and Seed Uniformity and Multiplication to Ensure Common Bean (Phaseolus vulgaris L.) var. Liborino

by Diana Peláez, Paula A. Aguilar, Mariana Mercado, Felipe López-Hernández, Manuel Guzmán, Esteban Burbano-Erazo, Kate Denning-James, Clara I. Medina, Matthew W. Blair, José J. De Vega and Andrés J. Cortés

Agronomy 2022, 12(10), 2285; https://doi.org/10.3390/agronomy12102285 - 23 Sep 2022

Cited by 14 | Viewed by 3235

Abstract

Seed uniformity and stability testing, and multiplication, are key steps in the seed supply chain of the common bean (Phaseolus vulgaris L.) and other crops. Optimizing agronomical practices in these phases can ultimately ensure seed quality and availability, and germplasm prospective utilization. [...] Read more.

Seed uniformity and stability testing, and multiplication, are key steps in the seed supply chain of the common bean (Phaseolus vulgaris L.) and other crops. Optimizing agronomical practices in these phases can ultimately ensure seed quality and availability, and germplasm prospective utilization. However, farmers have rarely standardized seed testing and propagation protocols in local common bean landraces conserved in situ. An example of this is the Liborino variety (var.), a promising yellow Andean common bean known for its presumably high digestibility and adaptation to the local conditions of the Cauca river canyon (northwest Andes of Colombia), but likely experiencing genetic erosion after decades of suboptimal propagation. Therefore, this work intended to evaluate and select locally adapted genotypes of common bean var. Liborino for commercial use, to be later multiplied, evaluated by participatory breeding, and eventually shared with farmers. Specifically, we evaluated 44 accessions of var. Liborino common bean in six adaption and yield field trials in the Cauca river canyon at 1100 and 1400 m a.s.l, and in AGROSAVIA’s “La Selva” research station at 2100 m a.s.l. In parallel, we carried out standardized seed multiplication of a Liborino genotype using best practices to guarantee uniformity and stability. From the 44 accessions, nine were well adapted to the tested local conditions. Four of these accessions exhibited a bush type growth habit, while the remaining five were climbers. The trials revealed maximum average extrapolated yields of up to 1169.4 ± 228.4 kg ha⁻¹ for the bush types (G8152) and up to 1720.0 ± 588.4 kg ha⁻¹ for the climbers (G51018), both at 2100 m a.s.l. Three climbing accessions matched farmers’ expectations for seed coat color and shape, according to a participatory selection exercise. Uniform and stable seed of the selected genotype was delivered in 2022 to 39 farmers, ~6.5 kg of seeds per farmer. Our results will allow implementing bean genetic improvement pipelines, promoting var. Liborino commercialization, and boosting the economic and sustainable development of the rural communities in the Cauca river canyon. Seed uniformity testing and multiplication pipelines must be extended to other bean landraces conserved in situ. Full article

(This article belongs to the Special Issue Legumes Cultivars and Their Genetic Improvements)

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13 pages, 3744 KiB

Open AccessEditor’s ChoiceArticle

UAV Multispectral Data: A Reliable Approach for Managing Phosphate-Solubilizing Bacteria in Common Bean

by Antonia Erica Santos de Souza, Marcelo Rodrigues Barbosa Júnior, Bruno Rafael de Almeida Moreira, Rouverson Pereira da Silva and Leandro Borges Lemos

Agronomy 2022, 12(10), 2284; https://doi.org/10.3390/agronomy12102284 - 23 Sep 2022

Cited by 3 | Viewed by 2524

Abstract

Remote sensing can offer stakeholders opportunities to make precise and accurate decisions on agricultural activities. For instance, farmers can exploit aircraft systems to acquire survey-level, high-resolution imagery data for crop and soil management. Therefore, the objective of this study was to analyze whether [...] Read more.

Remote sensing can offer stakeholders opportunities to make precise and accurate decisions on agricultural activities. For instance, farmers can exploit aircraft systems to acquire survey-level, high-resolution imagery data for crop and soil management. Therefore, the objective of this study was to analyze whether an unmanned aerial vehicle (UAV) allows for the assessment and monitoring of biofertilization of the common bean upon vegetation indices (VIs). The biological treatment of the legume crop included its inoculation with phosphate-solubilizing bacteria (PSB), namely Bacillus subtilis and B. megaterium. Indicators of photosynthetic performance, such as chlorophylls (a and b) and carotenoids, were measured from actively growing leaves to determine effectiveness. In addition, images were acquired in the field, both spatially and temporally, to establish functional relationships between biometric and computational features. Microorganisms manifested as growth-promoting agents to the crop as they significantly increased its quantities of light-harvesting pigments. VIs allowed for predicting their impact on photosynthetic performance, making them on-site markers of PSB. Therefore, this research can provide insights into the remote, non-destructive mapping of spectral changes in the common bean upon the application of PSB. Imagery data from UAV would enable producers to generate information on the crop to intervene in the field at the right time and place for improved utilization of biofertilizers. Full article

(This article belongs to the Special Issue Research Advances in Digital Technologies to Improve Agricultural Productivity)

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14 pages, 858 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of One-Time Applications of Foliar Applied Auxin Co-Applied with Surfactant for Use in Commercial Cutting Propagation

by Anthony T. Bowden, Patricia R. Knight, Jenny B. Ryals, Christine E. H. Coker, Scott A. Langlois, Shaun R. Broderick, Eugene K. Blythe, Hamidou F. Sakhanokho and Ebrahiem M. Babiker

Agronomy 2022, 12(10), 2243; https://doi.org/10.3390/agronomy12102243 - 20 Sep 2022

Cited by 4 | Viewed by 3075

Abstract

Use of foliar auxin applications are increasing in the nursery and greenhouse industry. However, previous research has shown that insufficient auxin is absorbed or translocated to the site of action when foliar auxin applications are used. It is theorized that adding surfactants to [...] Read more.

Use of foliar auxin applications are increasing in the nursery and greenhouse industry. However, previous research has shown that insufficient auxin is absorbed or translocated to the site of action when foliar auxin applications are used. It is theorized that adding surfactants to foliar applications of auxin may help with the absorption and translocation of auxin to the site of action. Research was conducted to determine whether adding surfactants to one-time foliar applications of indole-3-butyric acid (IBA) would be as effective as the current industry standard, the basal quick-dip. Terminal, semi-hardwood cuttings of Red Cascade™ miniature climbing rose (Rosa ‘MOORcap’), common camellia (Camellia japonica) and ‘Southern Charm’ magnolia (Magnolia grandiflora ‘Southern Charm’) were sprayed to the drip point using Hortus IBA Water Soluble Salts™ at concentrations of 0 ppm, 50 ppm, 75 ppm, or 100 ppm for rose cuttings or 0 ppm, 500 ppm, 1000 ppm, or 1500 ppm IBA for camellia or magnolia. To serve as an industry control, the basal end of cuttings was immersed for 3-s in a solution of either 250 ppm, 4000 ppm or 2500 ppm for rose, camellia, or magnolia, respectively. A foliar application of 1500 ppm after sticking was as effective as the basal quick-dip for cuttings of ‘Southern Charm’, while other spray treatments were less effective. A basal quick-dip was more effective than a foliar spray for rooting cuttings of camellia. Auxin rate had no impact on rooting of Red Cascade^™ miniature rose. The goal of commercial plant propagation is to produce high-quality rooted cuttings as quickly as possible. Plant propagation places a large demand on labor within the nursery industry, with one recent report being that labor accounts for >50% of a nursery’s budget. Our results from this trial affirm the results reported by similar trials into foliar applications of auxin suggests that the benefits of foliar applications are species dependent Further work is warranted on examining other auxin and surfactant formulations. Full article

(This article belongs to the Collection Propagation and Conservation of Horticultural Plants: In Vitro and In Vivo)

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16 pages, 3340 KiB

Open AccessEditor’s ChoiceArticle

Monitoring Growth Status of Winter Oilseed Rape by NDVI and NDYI Derived from UAV-Based Red–Green–Blue Imagery

by Nazanin Zamani-Noor and Dominik Feistkorn

Agronomy 2022, 12(9), 2212; https://doi.org/10.3390/agronomy12092212 - 16 Sep 2022

Cited by 15 | Viewed by 3491

Abstract

The current study aimed to evaluate the potential of the normalized difference vegetation index (NDVI), and the normalized difference yellowness index (NDYI) derived from red–green–blue (RGB) imaging to monitor the growth status of winter oilseed rape from seeding to the ripening stage. Subsequently, [...] Read more.

The current study aimed to evaluate the potential of the normalized difference vegetation index (NDVI), and the normalized difference yellowness index (NDYI) derived from red–green–blue (RGB) imaging to monitor the growth status of winter oilseed rape from seeding to the ripening stage. Subsequently, collected values were used to evaluate their correlations with the yield of oilseed rape. Field trials with three seed densities and three nitrogen rates were conducted for two years in Salzdahlum, Germany. The images were rapidly taken by an unmanned aerial vehicle carrying a Micasense Altum multi-spectral camera at 25 m altitudes. The NDVI and NDYI values for each plot were calculated from the reflectance at RGB and near-infrared (NIR) bands’ wavelengths pictured in a reconstructed and segmented ortho-mosaic. The findings support the potential of phenotyping data derived from NDVI and NDYI time series for precise oilseed rape phenological monitoring with all growth stages, such as the seedling stage and crop growth before winter, the formation of side shoots and stem elongation after winter, the flowering stage, maturity, ripening, and senescence stages according to the crop calendar. However, in comparing the correlation results between NDVI and NDYI with the final yield, the NDVI values turn out to be more reliable than the NDYI for the real-time remote sensing monitoring of winter oilseed rape growth in the whole season in the study area. In contrast, the correlation between NDYI and the yield revealed that the NDYI value is more suitable for monitoring oilseed rape genotypes during flowering stages. Full article

(This article belongs to the Section Precision and Digital Agriculture)

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15 pages, 998 KiB

Open AccessEditor’s ChoiceArticle

The Effects of Agricultural Socialized Services on Sustainable Agricultural Practice Adoption among Smallholder Farmers in China

by Meili Huan, Yajuan Li, Liang Chi and Shaoguo Zhan

Agronomy 2022, 12(9), 2198; https://doi.org/10.3390/agronomy12092198 - 15 Sep 2022

Cited by 29 | Viewed by 4021

Abstract

In recent years, a growing body of literature has explored the determinants and impacts of sustainable agricultural technologies. However, little is known about the relationship between agricultural socialized services that have reshaped the smallholder agricultural system and promoted scale operation in rural China [...] Read more.

In recent years, a growing body of literature has explored the determinants and impacts of sustainable agricultural technologies. However, little is known about the relationship between agricultural socialized services that have reshaped the smallholder agricultural system and promoted scale operation in rural China and environmentally friendly agricultural innovation adoption of the farm. Our study examines the effects of agricultural socialized services on the adoption of sustainable agricultural practices (SAPs). In this study, we capture the number of SAPs adopted, unlike most existing studies that analyze the dichotomous decision of agricultural technology adoption. We apply an endogenous-treatment Poisson regression model to analyze using a national representative farm-level survey data set with 1357 farm households from 132 villages in China. The results show that socialized service use has a significantly positive effect on the number of SAPs adopted. Our results suggest that agricultural socialized services can promote the adoption of sustainable agricultural technologies among smallholders, and thus help transform conventional agriculture into sustainable agriculture. Full article

(This article belongs to the Special Issue Economy and Sociology in Sustainable Agriculture)

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12 pages, 26420 KiB

Open AccessEditor’s ChoiceArticle

Effects of Bacillus amyloliquefaciens QST713 on Photosynthesis and Antioxidant Characteristics of Alfalfa (Medicago sativa L.) under Drought Stress

by Lingjuan Han, Miaoling Zhang, Lixia Du, Li Zhang and Bin Li

Agronomy 2022, 12(9), 2177; https://doi.org/10.3390/agronomy12092177 - 14 Sep 2022

Cited by 28 | Viewed by 3112

Abstract

Drought stress is a prevalent abiotic stress that adversely affects multiple physiological processes in plants, especially their photosynthetic capacity. Application of plant growth–promoting rhizobacteria (PGPR) has been considered as an eco-friendly strategy to ameliorate the deleterious effects of drought stress on plants. The [...] Read more.

Drought stress is a prevalent abiotic stress that adversely affects multiple physiological processes in plants, especially their photosynthetic capacity. Application of plant growth–promoting rhizobacteria (PGPR) has been considered as an eco-friendly strategy to ameliorate the deleterious effects of drought stress on plants. The present study was carried out to investigate the effects of Bacillus amyloliquefaciens QST713 on plant growth, leaf relative water content (RWC), photosynthesis processes, photosynthetic pigment content and antioxidant enzyme activities in two alfalfa varieties, Galalxie Max (drought-tolerant) and Saidi 7 (drought-sensitive) under drought conditions. The results showed that drought stress significantly declined plant biomass production, RWC, photosynthetic pigment content (Chl a, Chl b and carotenoids) and photosynthetic gas exchange parameters (transpiration rate (Tr), stomatal conductance (Gs) and intercellular CO₂ concentration (Ci)), whereas it enhanced the enzymatic activity of peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) in both cultivars. In contrast, the inoculation of the bacillus strain QST713 was more effective on plant growth, showing higher plant biomass production compared to the non-inoculated plants under drought stress. Moreover, the application of QST713 significantly promoted the content of RWC, the accumulation of chlorophyll content and the activities of antioxidant enzymes as well as enhanced the photosynthetic capacity of alfalfa seedlings under drought stress. These results suggest that QST713 could be considered as a promising bio-inoculant for plants exposed to environmental stresses. Full article

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26 pages, 4469 KiB

Open AccessEditor’s ChoiceArticle

Effect of a Biostimulant Based on Polyphenols and Glycine Betaine on Tomato Plants’ Responses to Salt Stress

by Javier Zuzunaga-Rosas, Sara González-Orenga, Ana Maria Tofei, Monica Boscaiu, Héctor Moreno-Ramón, Sara Ibáñez-Asensio and Oscar Vicente

Agronomy 2022, 12(9), 2142; https://doi.org/10.3390/agronomy12092142 - 9 Sep 2022

Cited by 24 | Viewed by 4715

Abstract

Climate change accentuates abiotic stress conditions putting at risk several commercial cultivars particularly vulnerable to salinity in the early stages of development, which makes adopting new technologies in tune with the environment necessary to mitigate its impact. In this study, we tested the [...] Read more.

Climate change accentuates abiotic stress conditions putting at risk several commercial cultivars particularly vulnerable to salinity in the early stages of development, which makes adopting new technologies in tune with the environment necessary to mitigate its impact. In this study, we tested the possible effects of a commercial biostimulant (BALOX^®) on enhancing salt stress tolerance in salt-treated tomato plants, analysing plant growth and several stress biochemical markers: photosynthetic pigments, ion contents in roots and leaves, leaf concentrations of different osmolytes, oxidative stress markers, non-enzymatic antioxidants, and the specific activities of major antioxidant enzymes. The experimental design consisted of three soil salinity levels (non-saline, saline, and very saline), two biostimulant doses (0.4 mL and 0.8 mL of the BALOX^® stock per litre of irrigation water), and the non-treated control (without biostimulant), evaluated at 30 and 60 days of treatment. The biostimulant favoured plant growth, especially at the root level and in saline soils. In addition, it helped reduce Na⁺ and Cl⁻ uptake by the roots and seemed to stimulate, to some extent, K⁺ and Ca²⁺ transport to the aerial part of the plant. The BALOX^® application significantly reduced the level of stress affecting the plants in saline soils, as shown by the decrease in the contents of proline and oxidative stress biomarkers and the activity of salt-induced antioxidant enzymes. Some of the biostimulant effects were also observed under low salinity conditions; therefore, in addition to enhancing salt stress responses, BALOX^® appears to stimulate the growth of tomato plants through a general improvement of photosynthesis and primary metabolism. Full article

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18 pages, 3054 KiB

Open AccessEditor’s ChoiceArticle

Understanding the Role of Physiological and Agronomical Traits during Drought Recovery as a Determinant of Differential Drought Stress Tolerance in Barley

by Md. Hasanuzzaman, Lana Shabala, Timothy J. Brodribb, Meixue Zhou and Sergey Shabala

Agronomy 2022, 12(9), 2136; https://doi.org/10.3390/agronomy12092136 - 8 Sep 2022

Cited by 8 | Viewed by 2793

Abstract

The fast and efficient recovery could be an important trait defining the efficacy of plant drought adaptation. In this work, we aimed to develop a set of simple and appropriate physiological proxies that could be used as reliable indicators to predict plant drought [...] Read more.

The fast and efficient recovery could be an important trait defining the efficacy of plant drought adaptation. In this work, we aimed to develop a set of simple and appropriate physiological proxies that could be used as reliable indicators to predict plant drought responses and validate the role of specific physiological traits such as root length, stomata density, and residual transpiration, in the drought tolerance and recovery in barley. Eighty barley (Hordeum vulgare L.) genotypes were subjected to progressive droughting until the soil moisture level reached 10%, followed by rewatering. Plants were visually scored at the end of drought period and two weeks after rewatering. SPAD values and chlorophyll fluorescence F_v/F_m ratio were also measured, alongside with stomatal density (SD) and residual transpiration (RT). The same genotypes were germinated in paper rolls treated with 15% (w/v) of polyethylene glycol (PEG) 8000 by quantification of changes in the root growth patterns. Responses to drought stress varied among the genotypes, and drought tolerance and recovery scores were significantly correlated with each other. Changes in SPAD value, F_v/F_m ratio and root length were significantly correlated with the drought tolerance and recovery indices. Both indices correlated strongly with the SD and RT of irrigated plants, although in an unexpected direction. We have also correlated the extent of plants’ drought tolerance to their ability to grow in saline soils (a condition often termed a “physiological drought”) and found a positive association between these two traits. The fact that drought tolerant genotype also possessed higher salinity tolerance implies some common mechanisms conferring both traits. Plants having less SD and more RT under irrigated conditions showed higher drought tolerance. It is concluded that lower SD and higher RT under optimal conditions may be used as proxies for drought tolerance in barley. Full article

(This article belongs to the Collection Crop Breeding for Stress Tolerance)

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17 pages, 1306 KiB

Open AccessEditor’s ChoiceArticle

Enhancing Sustainability in Intensive Dill Cropping: Comparative Effects of Biobased Fertilizers vs. Inorganic Commodities on Greenhouse Gas Emissions, Crop Yield, and Soil Properties

by Encarnación Martínez-Sabater, María Dolores Pérez-Murcia, Francisco Javier Andreu-Rodríguez, Luciano Orden, Enrique Agulló, José Sáez-Tovar, Juan Martínez-Tome, María Ángeles Bustamante and Raul Moral

Agronomy 2022, 12(9), 2124; https://doi.org/10.3390/agronomy12092124 - 7 Sep 2022

Cited by 7 | Viewed by 2742

Abstract

The treatment and valorization of organic solid waste has become a promising alternative to increase intensive crop productivity while reducing its environmental impact. Currently, reusing improved organic waste as novel biofertilizers is a vital tool to adapt semiarid agricultural regions to climate change, [...] Read more.

The treatment and valorization of organic solid waste has become a promising alternative to increase intensive crop productivity while reducing its environmental impact. Currently, reusing improved organic waste as novel biofertilizers is a vital tool to adapt semiarid agricultural regions to climate change, but this has been scarcely studied in aromatic crops. The present study aims to assess the greenhouse gas emissions, soil properties, and crop yield of a dill crop using a drip irrigation system with a normalized N application rate of 160 kg N ha⁻¹. We compare eight different fertilizing scenarios grouped into organic-based (manures and compost) and inorganic-based inputs (NPK commodities and slow-release formulations). GHG fluxes were measured during the 57-day fertigation period using static chambers. Key soil properties were measured previous to fertilizer applications and at harvest, coinciding with crop yield estimations. An increase in soil organic carbon was observed with stabilized organic treatments at 0–20 cm soil depth. The results show that stabilized organic-based materials lowered NO₃⁻ concentrations in dill biomass more than synthetic fertilizers, producing similar yields to those with synthetic fertilizers. In general, N₂O emissions were positively affected by the treatments. Local specific emission factors for N₂O were determined (0.08%), which were substantially lower than the default value (0.51%) of IPCC. The cumulative CO₂ emissions were high in all the organic scenarios compared to the control treatment (277 kg C-CO₂ ha⁻¹), probably due to differences in labile organic C contents. Organic-based treatments showed multiple positive effects on crop quality, crop yields, and GHG mitigation potential. The use of organic amendments is an optimized N fertilizing strategy to promote circular economy and sustainability. Full article

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15 pages, 2807 KiB

Open AccessEditor’s ChoiceArticle

Prediction of the Effect of Nutrients on Plant Parameters of Rice by Artificial Neural Network

by Tanmoy Shankar, Ganesh Chandra Malik, Mahua Banerjee, Sudarshan Dutta, Subhashisa Praharaj, Sagar Lalichetti, Sahasransu Mohanty, Dipankar Bhattacharyay, Sagar Maitra, Ahmed Gaber, Ashok K. Das, Ayushi Sharma and Akbar Hossain

Agronomy 2022, 12(9), 2123; https://doi.org/10.3390/agronomy12092123 - 7 Sep 2022

Cited by 24 | Viewed by 4283

Abstract

Rice holds key importance in food and nutritional security across the globe. Nutrient management involving rice has been a matter of interest for a long time owing to the unique production environment of rice. In this research, an artificial neural network-based prediction model [...] Read more.

Rice holds key importance in food and nutritional security across the globe. Nutrient management involving rice has been a matter of interest for a long time owing to the unique production environment of rice. In this research, an artificial neural network-based prediction model was developed to understand the role of individual nutrients (N, P, K, Zn, and S) on different plant parameters (plant height, tiller number, dry matter production, leaf area index, grain yield, and straw yield) of rice. A feed-forward neural network with back-propagation training was developed using the neural network (nnet) toolbox available in Matlab. For the training of the model, data obtained from two consecutive crop seasons over two years (a total of four crops of rice) were used. Nutrients interact with each other, and the resulting effect is an outcome of such interaction; hence, understanding the role of individual nutrients under field conditions becomes difficult. In the present study, an attempt was made to understand the role of individual nutrients in achieving crop growth and yield using an artificial neural network-based prediction model. The model predicts that growth parameters such as plant height, tiller number, and leaf area index often achieve their maximum performance at below the maximum applied dose, while the maximum yield in most cases is achieved at 100% N, P, K, Zn, and S dose. In addition, the present study attempted to understand the impact of individual nutrients on both plant growth and yield in order to optimize nutrient recommendation and nutrient management, thereby minimizing environmental pollution and wastage of nutrients. Full article

(This article belongs to the Special Issue The New Agricultural Revolution: From Traditional Farms to Smart Agriculture—New Technologies in Agriculture 5.0)

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20 pages, 1777 KiB

Open AccessEditor’s ChoiceArticle

Policy Gaps Related to Sustainability in Hungarian Agribusiness Development

by Edit Hoyk, Ádám Szalai, András Palkovics and Jenő Zsolt Farkas

Agronomy 2022, 12(9), 2084; https://doi.org/10.3390/agronomy12092084 - 1 Sep 2022

Cited by 14 | Viewed by 3974

Abstract

The world’s agriculture faces many challenges nowadays, such as tackling the effects of climate change, conserving agrobiodiversity, or feeding the Earth’s growing population. These issues often induce conflicting development directions, such as digitalization and ecologization, as the case of the European Union’s Common [...] Read more.

The world’s agriculture faces many challenges nowadays, such as tackling the effects of climate change, conserving agrobiodiversity, or feeding the Earth’s growing population. These issues often induce conflicting development directions, such as digitalization and ecologization, as the case of the European Union’s Common Agricultural Policy (CAP) shows. In the last decades, policymakers have focused mainly on greening agricultural production and the food industry, and now the CAP is part of the European Green Deal. In our research, we assessed the sustainability problems affecting the agribusiness sector and food consumption in Hungary using descriptive statistical analysis. On the other hand, we examined the latest sectoral development documents (Digital Agricultural Strategy, Digital Food Industry Strategy) in order to find out to what extent they answer the identified issues. Our results revealed that the Hungarian agribusiness sector is struggling with several sustainability challenges, which do not receive adequate attention from policymakers. The newest development strategies are characterized by forced digitalization efforts, while their applicability and effectiveness are uncertain. Because of similar development trajectories, we believe most of our results are relevant to other Central Eastern European Member states. Hence, further CAP and national policy reforms are needed to make Europe’s agribusiness sector more sustainable. Full article

(This article belongs to the Section Farming Sustainability)

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19 pages, 473 KiB

Open AccessEditor’s ChoiceArticle

Effect of Biochar and Inorganic or Organic Fertilizer Co-Application on Soil Properties, Plant Growth and Nutrient Content in Swiss Chard

by Anna Rita Rivelli and Angela Libutti

Agronomy 2022, 12(9), 2089; https://doi.org/10.3390/agronomy12092089 - 1 Sep 2022

Cited by 30 | Viewed by 6073

Abstract

From the perspective of sustainable agri-food production, farmers need to make the best use of natural resources. Biochar can be a solution to adopt a more sustainable way of farming. Despite its environmental and agronomic advantages, biochar has a low plant nutrient value. [...] Read more.

From the perspective of sustainable agri-food production, farmers need to make the best use of natural resources. Biochar can be a solution to adopt a more sustainable way of farming. Despite its environmental and agronomic advantages, biochar has a low plant nutrient value. This study evaluated the effect of biochar and the co-application of an inorganic or organic fertilizer on the soil properties, growth and nutrient content of Swiss chard (Beta vulgaris L. var. cycla, Caryophyllales order, Chenopodiaceae family). The experiment consisted of two factors: biochar type (from vineyard prunings and wood chips) and fertilizing source (ammonium nitrate and vermicompost). Biochars were applied at a 2% rate (w/w) and fertilizers at a dose providing 280 kg N ha⁻¹. The soil properties (pH, EC, extractable anions, cations, total N, Corg and C/N ratio) were measured before the plants were transplanted and at the end of the growing cycle, along with the growth parameters (leaf number, length and fresh weight) of each leaf cut, the productive parameters (total number of leaves and yield per plant) at the end of the growing cycle and the leaf content of anions (NO₃⁻, P₂O₄³⁻, SO₄²⁻), cations (NH₄⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺) and total N. The co-application of biochar and a fertilizing source had a positive effect on soil properties and leaf nutrient content. Vermicompost increased plant growth by 22% and plant yield by 116%, in contrast to biochar, and increased limited leaf NO₃⁻ accumulation by about 81% in comparison to ammonium nitrate. The co-application of biochar and vermicompost is the better option to increase Swiss chard yield while preserving the nutritional and health qualities of the product. Full article

(This article belongs to the Topic Innovation and Solution for Sustainable Agriculture)

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18 pages, 479 KiB

Open AccessEditor’s ChoiceCommunication

Effect of Clover Sward Management on Nitrogen Fixation and Performance of Following Spring- and Winter Wheat Crops; Results of a 3-Year Pilot Study

by Andrew Wilkinson, John N. Wilkinson, Peter Shotton, Mick Eyre, Gultakin Hasanaliyeva, Paul Bilsborrow, Carlo Leifert and Leonidas Rempelos

Agronomy 2022, 12(9), 2085; https://doi.org/10.3390/agronomy12092085 - 1 Sep 2022

Cited by 7 | Viewed by 2383

Abstract

Wheat yields in organic production are significantly lower than those achieved in conventional farming systems and in Northern Europe organic farmers also struggle to achieve the processing quality levels demanded by millers and bakers, especially in winter-wheat crops. Here, we report the findings [...] Read more.

Wheat yields in organic production are significantly lower than those achieved in conventional farming systems and in Northern Europe organic farmers also struggle to achieve the processing quality levels demanded by millers and bakers, especially in winter-wheat crops. Here, we report the findings of a 3-year pilot study which investigated the potential of increasing grain yields and both standard processing (e.g., grain protein levels and specific weights) and selected nutritional (tocopherol and tocotrienol isomers) quality parameters via (i) changes in the management of clover crops grown before wheat (Rhizobium seed inoculation, application of greenwaste compost to clover swards) and (ii) use of new varieties developed in both the UK and continental Europe. Results indicate that the use of compost amendment to preceding clover swards significantly increased the grain protein levels in the three winter-wheat, but not the four spring-wheat varieties, and also significantly increases grain yields in one winter-wheat variety (Greina). In contrast, the use of Rhizobium-inoculation was found to significantly reduce protein concentrations in the winter-, but not spring wheat varieties, and had no significant effect on grain yields in both winter and spring wheat. However, analysis of variance detected significant interactions between Rhizobium seed inocula in clover pre-crops and (a) compost application for grain specific weights in winter-wheat and grain hardness in spring wheat crops and (b) variety for grain protein content in spring wheat crops. No significant effect of clover pre-crop management on tocopherol and tocotrienol isomer profiles could be detected, although significant differences between varieties were detected in both winter and spring wheat. Results of this pilot study need to be confirmed in future trials, but indicate that both (a) changes in clover-management practices and (b) the selections of wheat varieties that are more suitable for organic farming systems has the potential to increase grain yield and allow organic farmers to more frequently achieve baking or milling grade quality. Full article

(This article belongs to the Special Issue Integrated Soil, Crop and Human Nutrition and Health Management in Organic Agriculture)

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28 pages, 5678 KiB

Open AccessEditor’s ChoiceArticle

Applying Spatial Statistical Analysis to Ordinal Data for Soybean Iron Deficiency Chlorosis

by Zhanyou Xu, Steven B. Cannon and William D. Beavis

Agronomy 2022, 12(9), 2095; https://doi.org/10.3390/agronomy12092095 - 1 Sep 2022

Cited by 3 | Viewed by 2444

Abstract

Accounting for field variation patterns plays a crucial role in interpreting phenotype data and, thus, in plant breeding. Several spatial models have been developed to account for field variation. Spatial analyses show that spatial models can successfully increase the quality of phenotype measurements [...] Read more.

Accounting for field variation patterns plays a crucial role in interpreting phenotype data and, thus, in plant breeding. Several spatial models have been developed to account for field variation. Spatial analyses show that spatial models can successfully increase the quality of phenotype measurements and subsequent selection accuracy for continuous data types such as grain yield and plant height. The phenotypic data for stress traits are usually recorded in ordinal data scores but are traditionally treated as numerical values with normal distribution, such as iron deficiency chlorosis (IDC). The effectiveness of spatial adjustment for ordinal data has not been systematically compared. The research objective described here is to evaluate methods for spatial adjustment of ordinal data, using soybean IDC as an example. Comparisons of adjustment effectiveness for spatial autocorrelation were conducted among eight different models. The models were divided into three groups: Group I, moving average grid adjustment; group II, geospatial autoregressive regression (SAR) models; and Group III, tensor product penalized P-splines. Results from the model comparison show that the effectiveness of the models depends on the severity of field variation, the irregularity of the variation pattern, and the model used. The geospatial SAR models outperform the other models for ordinal IDC data. Prediction accuracy for the lines planted in the IDC high-pressure area is 11.9% higher than those planted in low-IDC-pressure regions. The relative efficiency of the mixed SAR model is 175%, relative to the baseline ordinary least squares model. Even though the geospatial SAR model is the best among all the compared models, the efficiency is not as good for ordinal data types as for numeric data. Full article

(This article belongs to the Special Issue Predictions and Estimations in Agricultural Production under a Changing Climate)

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14 pages, 1175 KiB

Open AccessEditor’s ChoiceArticle

Synergistic Effect of Plant-Growth-Promoting Rhizobacteria Improves Strawberry Growth and Flowering with Soil Salinization and Increased Atmospheric CO₂ Levels and Temperature Conditions

by Susana Redondo-Gómez, Jesús V. García-López, Jennifer Mesa-Marín, Eloísa Pajuelo, Ignacio D. Rodriguez-Llorente and Enrique Mateos-Naranjo

Agronomy 2022, 12(9), 2082; https://doi.org/10.3390/agronomy12092082 - 31 Aug 2022

Cited by 23 | Viewed by 3440

Abstract

Biofertilization with plant-growth-promoting rhizobacteria (PGPR) can positively affect the growth and health of host plants and reinforce their tolerance of stressors. Here, we investigate the use of isolated PGPR consortia from halophytes to improve strawberry growth and flowering performance under saline and elevated [...] Read more.

Biofertilization with plant-growth-promoting rhizobacteria (PGPR) can positively affect the growth and health of host plants and reinforce their tolerance of stressors. Here, we investigate the use of isolated PGPR consortia from halophytes to improve strawberry growth and flowering performance under saline and elevated CO₂ and temperature conditions. Growth, flower bud production, and the photosynthetic apparatus response were determined in strawberry plants grown at 0 and 85 mmol L⁻¹ NaCl and in two atmospheric CO₂-temperature combinations (400/700 ppm and 25/+4 °C, respectively). Biofertilization improved strawberry plant growth and flower bud production, independently of salinity conditions, at ambient CO₂ and 25 °C, while bacterial inoculation only had a positive effect on plant growth in the presence of salt in high CO₂ and at +4 °C. Biofertilizers 1 and 3 generated the largest biomass of strawberries at 400 ppm CO₂ and 0 and 85 mmol L⁻¹ NaCl, respectively, while biofertilizer 1 did so in the presence of salt and in an atmosphere enriched with CO₂ and at +4 °C. The effect of the consortia was mediated by bacterial strain PGP properties, rather than by an improvement in the photosynthetic rate of the plants. Furthermore, biofertilizers 1 and 2 increased the number of flower buds in the absence of salt, while biofertilizers 3 and 4 did so for salt-inoculated plants at 400 ppm CO₂ and at 25 °C. There was no effect of inoculation on flower bud production of plants grown at high CO₂ and at +4 °C. Finally, we concluded that the effect of bacterial inoculation on strawberry growth and flowering depended on the type of bacterial strain and growth conditions. This highlights the importance of developing studies considering stress interaction to assess the real potential of biofertilizers. Full article

(This article belongs to the Special Issue How Could Microorganisms Benefit the Agriculture Environment?)

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15 pages, 3479 KiB

Open AccessEditor’s ChoiceArticle

Extreme Weather and Grazing Management Influence Soil Carbon and Compaction

by Anish Subedi, Dorcas Franklin, Miguel Cabrera, Subash Dahal, Dennis Hancock, Amanda McPherson and Lawton Stewart

Agronomy 2022, 12(9), 2073; https://doi.org/10.3390/agronomy12092073 - 30 Aug 2022

Cited by 2 | Viewed by 2292

Abstract

Understanding the influence of cattle grazing on soil carbon and bulk density during extreme dry to wet periods can help us design more resilient and sustainable grazing systems for low-input management scenarios. A study was conducted to evaluate changes in loss-on-ignition (LOI) carbon [...] Read more.

Understanding the influence of cattle grazing on soil carbon and bulk density during extreme dry to wet periods can help us design more resilient and sustainable grazing systems for low-input management scenarios. A study was conducted to evaluate changes in loss-on-ignition (LOI) carbon and bulk density (BD) in the top 20 cm soil layer when eight continuous grazing (CG) pastures were converted to either continuous grazing with hay distribution (CHD-4) or strategic grazing (STR-4). STR included lure management of cattle with movable-equipages, exclusion and over-seeding erosion-vulnerable areas, and a relaxed rotational grazing. Changes in relationships between cattle density (CD), LOI, and BD were evaluated for change in grazing management from 2015 to 2018. Reduction in LOI carbon (0–5, 5–10, 10–20 cm) and BD (5–10 cm) were observed in both CHD and STR pastures in 2018. CD in 2015 had either no relationship or a negative relationship on LOI while in 2018, CD positively influenced LOI in CHD (0–5 cm) and STR (0–5 and 5–10 cm) pastures. STR had lower BD with higher CD further away from concentrated flow paths mirroring cattle movement. Exclusions in the STR pastures had the greatest reduction in BD. Even with reduced carbon in the 0–5 cm soil layer the reduction in BD in the 5–10 cm soil layer helped build resilience in grazing systems that experience extreme weather events such as going from very dry to extensively wet. Full article

(This article belongs to the Special Issue Advance in Grassland Productivity and Sustainability)

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18 pages, 3866 KiB

Open AccessEditor’s ChoiceArticle

SE-YOLOv5x: An Optimized Model Based on Transfer Learning and Visual Attention Mechanism for Identifying and Localizing Weeds and Vegetables

by Jian-Lin Zhang, Wen-Hao Su, He-Yi Zhang and Yankun Peng

Agronomy 2022, 12(9), 2061; https://doi.org/10.3390/agronomy12092061 - 29 Aug 2022

Cited by 36 | Viewed by 3825

Abstract

Weeds in the field affect the normal growth of lettuce crops by competing with them for resources such as water and sunlight. The increasing costs of weed management and limited herbicide choices are threatening the profitability, yield, and quality of lettuce. The application [...] Read more.

Weeds in the field affect the normal growth of lettuce crops by competing with them for resources such as water and sunlight. The increasing costs of weed management and limited herbicide choices are threatening the profitability, yield, and quality of lettuce. The application of intelligent weeding robots is an alternative to control intra-row weeds. The prerequisite for automatic weeding is accurate differentiation and rapid localization of different plants. In this study, a squeeze-and-excitation (SE) network combined with You Only Look Once v5 (SE-YOLOv5x) is proposed for weed-crop classification and lettuce localization in the field. Compared with models including classical support vector machines (SVM), YOLOv5x, single-shot multibox detector (SSD), and faster-RCNN, the SE-YOLOv5x exhibited the highest performance in weed and lettuce plant identifications, with precision, recall, mean average precision (mAP), and F1-score values of 97.6%, 95.6%, 97.1%, and 97.3%, respectively. Based on plant morphological characteristics, the SE-YOLOv5x model detected the location of lettuce stem emerging points in the field with an accuracy of 97.14%. This study demonstrates the capability of SE-YOLOv5x for the classification of lettuce and weeds and the localization of lettuce, which provides theoretical and technical support for automated weed control. Full article

(This article belongs to the Special Issue Computer Vision for Intelligent Crop Identification and Crop Protection)

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21 pages, 3780 KiB

Open AccessEditor’s ChoiceArticle

The Molecular Composition of Humic Acids in Permafrost Peats in the European Arctic as Paleorecord of the Environmental Conditions of the Holocene

by Roman Vasilevich, Evgeny Lodygin and Evgeny Abakumov

Agronomy 2022, 12(9), 2053; https://doi.org/10.3390/agronomy12092053 - 28 Aug 2022

Cited by 13 | Viewed by 2151

Abstract

The purpose of our research is focused on examination of the transformation regularities of molecular composition of humic acids (HAs) in the hummocky frozen peatlands of the European Arctic as a marker of climatic changes in the Holocene, and assessment of the stabilization [...] Read more.

The purpose of our research is focused on examination of the transformation regularities of molecular composition of humic acids (HAs) in the hummocky frozen peatlands of the European Arctic as a marker of climatic changes in the Holocene, and assessment of the stabilization of soil organic matter under the conditions of modern climatic warming. Histosols located in the two subzones of the European Arctic served as the research subjects. This territory is actively used for reindeer breeding, which is a vital agricultural branch in the Far North of the Russian Federation. The data obtained reveal the main trends in the formation of HAs from Arctic peatlands under different environmental conditions. Modern peat sediments (top layers) in the middle and late Holocene period formed out of bryophyte residues and contained HAs with long-chain carbohydrate and paraffin structures in their composition. These structures enlarged the dynamic radii of HA molecules, and, thus, caused high average molecular weight values. The more favorable climatic conditions of the early Holocene (the Atlantic optimum) defined the botanical composition of peat, which was dominated by tree and sedge communities with high contents of lignin components and, as a consequence, a larger share of aromatic fragments, characterized by thermo-biodynamic resistance in HAs of horizons in the lower and central profile parts. The molecules of HAs are an archive of paleoclimatic records. The Subboreal and Subatlantic climatic conditions determined the specifics of vegetation precursors and, as a result, the molecular structure of HAs in seasonally thawed layers, with a predominance of long-chain aliphatic fragments. The conversion of HAs from Histosols led to an increase in the proportion of carbon in branched and short-chain paraffinic structures with their subsequent cyclization and aromatization. The results of this process are most clearly manifested in layers formed during the Holocene I and II climatic optima. Higher biologically active temperatures of the seasonally thawed layer of soils at bare spots (without vegetation) determined the accumulation of thermodynamically more stable HA molecules with a high content of aromatic fragments. This contributed to both the stabilization of the SOM and the conservation of peatlands in general. Full article

(This article belongs to the Topic Frontier Studies in Composition of Humic Substances and Soil Organic Matter)

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30 pages, 333 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of Global Composite Collection Reveals Agronomically Superior Germplasm Accessions for Chickpea Improvement

by Muneendra K. Singh, Manish Roorkiwal, Abhishek Rathore, Khela Ram Soren, Motisagar S. Pithia, Mohammad Yasin, Surendra Barpete, Servejeet Singh, Rutwik Barmukh, Roma Rani Das, Priyanka Gangwar, Chana P. Chetariya, Priyanka Joshi, Sushil K. Chaturvedi, Rakesh M. Javia, Vallabhbhai V. Ramani, Aladdin Hamwieh, Shiv Kumar, Chellapilla Bharadwaj, Narendra P. Singh and Rajeev K. Varshney Show full author list Hide full author list

Agronomy 2022, 12(9), 2013; https://doi.org/10.3390/agronomy12092013 - 26 Aug 2022

Cited by 2 | Viewed by 3004

Abstract

The rich genetic diversity existing within exotic, indigenous, and diverse germplasm lays the foundation for the continuous improvement of crop cultivars. The composite collection has been suggested as a gateway to identifying superior germplasm for use in crop improvement programs. Here, a chickpea [...] Read more.

The rich genetic diversity existing within exotic, indigenous, and diverse germplasm lays the foundation for the continuous improvement of crop cultivars. The composite collection has been suggested as a gateway to identifying superior germplasm for use in crop improvement programs. Here, a chickpea global composite collection was evaluated at five locations in India over two years for five agronomic traits to identify agronomically superior accessions. The desi, kabuli, and intermediate types of chickpea accessions differed significantly for plant height (PLHT) and 100-seed weight (100 SW). In contrast, the intermediate type differed substantially from kabuli for days to maturity (DM). Several highly significant trait correlations were detected across different locations. The most stable and promising accessions from each of the five locations were prioritised based on their superior performance over the best-performing check cultivar. Accordingly, the selected germplasm accessions of desi type showed up to 176% higher seed yield (SY), 29% lower flowering time, 21% fewer maturity days, 64% increase in PLHT, and 183% larger seeds than the check cultivar JG11 or Annigeri. The prioritised kabuli accessions displayed up to 270% more yield, 13% less flowering time, 8% fewer maturity days, 111% increase in PLHT, and 41% larger seeds over the check cultivar KAK2. While the intermediate type accessions had up to 169% better yield, 1% early flowering, 3% early maturity, 54% taller plants, and 25% bigger seeds over the check cultivar JG 11 or KAK2. These accessions can be utilised in chickpea improvement programs to develop high-yielding, early flowering, short duration, taller, and large-seeded varieties with a broad genetic base. Full article

(This article belongs to the Section Crop Breeding and Genetics)

22 pages, 2193 KiB

Open AccessEditor’s ChoiceArticle

Variation of Bio-Morphometric Traits and Antioxidant Compounds of Brassica oleracea L. Accessions in Relation to Drought Stress

by Hajer Ben Ammar, Valentina Picchi, Donata Arena, Simone Treccarichi, Giulia Bianchi, Roberto Lo Scalzo, Sonia Marghali and Ferdinando Branca

Agronomy 2022, 12(9), 2016; https://doi.org/10.3390/agronomy12092016 - 26 Aug 2022

Cited by 14 | Viewed by 2537

Abstract

Drought tolerance of Brassica crops can be genetically improved by establishing plant ideotypes with improved yield responses associated with agronomic traits and biochemical markers. The objective of this study was to compare 20 Brassica oleracea L. accessions grown under two different water treatments [...] Read more.

Drought tolerance of Brassica crops can be genetically improved by establishing plant ideotypes with improved yield responses associated with agronomic traits and biochemical markers. The objective of this study was to compare 20 Brassica oleracea L. accessions grown under two different water treatments (100% and 35% reintegration of evapotranspiration by irrigation) to select potential tolerant genotypes for organic cultivation based on several agronomic and biochemical parameters measured in response to drought stress. Significant differences were registered for the genotype and the irrigation regime and for their interaction (p < 0.0001 ***). A principal component analysis was performed to summarize the correlations among the analyzed phytochemicals and the stressed and not stressed genotypes and highlighted the importance of the antioxidant compounds as stress biomarkers. The present results showed that drought significantly reduces growth parameters and increases the amount of ascorbic acid and polyphenols compared to the irrigated control. Additionally, the results show that antioxidant metabolism increased by drought in some genotypes while others maintained a good biomass production by increasing the value of growth parameters considered. Based on the average sum of ranks (ASR) of morpho-physiological and biochemical parameters, the genotypes CR, CC, and BH were determined to be the most drought tolerant, whereas CI5, BU, and CV1 were determined to be the most susceptible. Due to the potential of these genotypes, further molecular and cellular research will be carried out to identify the genetic marker associated with the water stress response. Full article

(This article belongs to the Collection Abiotic Stress Tolerance in Plants: Towards a Sustainable Agriculture)

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13 pages, 1110 KiB

Open AccessEditor’s ChoiceArticle

Recovery of Grain Yield and Protein with Fertilizer Application Post Nitrogen Stress in Winter Wheat (Triticum aestivum L.)

by Joao Luis Bigatao Souza, Joao Arthur Antonangelo, Amanda de Oliveira Silva, Vaughn Reed and Brian Arnall

Agronomy 2022, 12(9), 2024; https://doi.org/10.3390/agronomy12092024 - 26 Aug 2022

Cited by 6 | Viewed by 2863

Abstract

Unfavorable weather conditions and lack of appropriate farm machinery often delay N application. This results in nitrogen (N) deficiency during the vegetative and early reproductive growth stages of winter wheat. The objective of this study was to evaluate the impact of N application [...] Read more.

Unfavorable weather conditions and lack of appropriate farm machinery often delay N application. This results in nitrogen (N) deficiency during the vegetative and early reproductive growth stages of winter wheat. The objective of this study was to evaluate the impact of N application timings (from tillering to flag leaf growth stages) on winter wheat grain yield and protein. The study was conducted across 12 site–years in Oklahoma, US. The treatments included a non-fertilized check, a pre-plant application of 100 kg N ha⁻¹, and ten in-season application timings at 100 kg of N ha⁻¹. The in-season treatment applications were initiated at the point when an N deficiency was visually identified by comparing the pre-plant treatment to the non-fertilized check. The treatments were applied in a progressive order every seven growing degree days (GDD > 0 °C) until a cumulative GDD of 63 was reached after visual deficiency (DAVD). All in-season treatments increased grain yield and protein as compared to the non-fertilized check, showing that N was a yield-limiting factor. The nitrogen applications made post Feekes 8 decreased grain yield when compared to pre-plant applications. Across this data set, that timing corresponded to a range of 21 to 63DAVD. The results suggested that forgoing N application until the growth stage Feekes 7, even when the visual N deficiency was highly apparent before that stage, had no negative impact on the yield, and it even increased the yield as compared to the pre-plant application in some cases. The plant developmental stage at which the N application takes place is more critical than the level of N deficiency. Our results show that N fertilizer applications should be made posteriorly to the crop dormancy to maximize both yield and protein, and that plants can recover from N deficiency when applications are made until the late-vegetative phase (Feekes 7). This document shows that winter wheat producers have a much wider N application window than traditionally believed. Full article

(This article belongs to the Section Soil and Plant Nutrition)

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31 pages, 3777 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Adaptation of Quinoa (Chenopodium quinoa Willd.) to Australian Environments

by Richard Snowball, Harmohinder S. Dhammu, Mario Francesco D’Antuono, David Troldahl, Ian Biggs, Callen Thompson, Mark Warmington, Amanda Pearce and Darshan L. Sharma

Agronomy 2022, 12(9), 2026; https://doi.org/10.3390/agronomy12092026 - 26 Aug 2022

Cited by 2 | Viewed by 2791

Abstract

Quinoa is being evaluated in cropping systems in many countries outside of its natural range of South America. Very few attempts have been made by farmers or researchers to grow or evaluate quinoa under Australian environments. Given the growing popularity of quinoa with [...] Read more.

Quinoa is being evaluated in cropping systems in many countries outside of its natural range of South America. Very few attempts have been made by farmers or researchers to grow or evaluate quinoa under Australian environments. Given the growing popularity of quinoa with consumers, new commercial opportunities for farmers and international interest in the crop, it was timely to undertake a comprehensive evaluation of the potential of quinoa in Australia. Two advanced selections and nine germplasm lines (six of Chilean and three of Bolivian origin) identified in an earlier project were tested in 23 field trials at 14 locations on mainland Australia. Targets included irrigated sites in tropical, Mediterranean, semi-arid and desert climates, and rain-fed sites of south-western Australia with a Mediterranean climate. The field experiments were either a randomised complete block design (RBCD) or a split plot/factorial design with 2–4 replicates, and a linear mixed model was used to compare the treatment lines. Seed yield of quinoa was highest when grown in winter and spring under rain-fed conditions in Geraldton, in spring and summer under irrigation at Bool Lagoon, and summer, autumn and winter under irrigation at Leeton. The highest seed yield achieved was 3 t/ha for a germplasm line from Chile, while the highest yield for a germplasm line from Bolivia was 2.6 t/ha. Advanced selections from Australia yielded well in comparison at most trial sites. Declining seed yield was associated with mean daily temperatures during seed development increasing above 17 °C, mean daily temperatures during flowering declining below 15 °C, and rainfall during seed development under rain-fed conditions falling below 50 mm. Seed produced at Bool Lagoon was the closest in colour to white quinoa imported from Peru; however, it was more than noticeably different. Seed produced at Geraldton and Leeton was significantly larger than from other field sites; however, none were larger than 2 mm in diameter as found in Royal white quinoa from Bolivia. Superior seed colour and seed size were associated with dry conditions at maturity and cool conditions during seed development, respectively. We conclude that quinoa can become a potential crop option for Australian agriculture by exploiting genetic diversity and supplementing with suitable management practices matched to agro-climatic environments. There are reasonable prospects to raise the seed yield potential in areas in all states, especially in the regions where quinoa grew well in our experiments. Full article

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17 pages, 1770 KiB

Open AccessEditor’s ChoiceArticle

Suitability Evaluation of Three Tropical Pasture Species (Mulato II, Gatton Panic, and Rhodes Grass) for Cultivation under a Subtropical Climate of Australia

by Priyanath Jayasinghe, Daniel J. Donaghy, David G. Barber, Keith G. Pembleton and Thiagarajah Ramilan

Agronomy 2022, 12(9), 2032; https://doi.org/10.3390/agronomy12092032 - 26 Aug 2022

Cited by 6 | Viewed by 3213

Abstract

Exploring improved tropical forages is considered to be an important approach in delivering quality and consistent feed options for dairy cattle in tropical and subtropical regions. The present study aimed to study the suitability of three improved tropical grasses, Chloris gayana ‘Rhodes grass [...] Read more.

Exploring improved tropical forages is considered to be an important approach in delivering quality and consistent feed options for dairy cattle in tropical and subtropical regions. The present study aimed to study the suitability of three improved tropical grasses, Chloris gayana ‘Rhodes grass cv. Reclaimer’ (RR), Megathyrsus maximus ‘Gatton Panic’ (GP), and Brachiaria ruziziensis x B. decumbens x B. brizantha ‘Brachiaria Mulato II’ (BM) evaluating their carbon assimilation, canopy structure, herbage plant–part accumulation and quality parameters under irrigated conditions. An experiment was conducted at Gatton Research Dairy (27°54′ S, 152°33′ E, 89 m asl) Queensland, Australia, which has a predominantly subtropical climate. Photosynthesis biochemistry, canopy structure, herbage accumulation, plant part composition, and nutritive value were evaluated. Photosynthesis biochemistry differed between pasture species. Efficiency of CO₂ assimilation was highest for GP and quantum efficiency was highest for BM. Pasture canopy structure was significantly affected by an interaction between pasture species and harvest. Forage biomass accumulation was highest in GP, while BM produced more leaf and less stem compared to both GP and RR. A greater leafy stratum and lower stemmy stratum depth were observed in the vertical sward structure of BM. Brachiaria Mulato II showed greater carbon partitioning to leaves, leaf: stem ratio, canopy, and leaf bulk density. It also demonstrated greater nutritive value (Total digestible nutrients (TDN), acid detergent fibre (ADF), neutral detergent fibre (NDF), neutral detergent insoluble protein (NDICP), Starch, nonfibre carbohydrates (NFC), metabolisable energy (ME), mineral profile (Mg, P, K, Fe, Zn) and dietary cation–anion difference (DCAD) for leaf, stem, and the whole plant. Greater quantum efficiency, leaf accumulation, and nutritive value of BM observed in the present study suggest BM as an attractive forage option for dairying that warrants further research in pasture-based systems in tropical and subtropical climates. Full article

(This article belongs to the Section Grassland and Pasture Science)

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12 pages, 1512 KiB

Open AccessEditor’s ChoiceArticle

Planting Date and Hybrid Affect Sugarcane Aphid Infestation, Yield, and Water Use Efficiency in Dryland Grain Sorghum

by Zane Jenkins, Sushil Thapa, Jourdan M. Bell, Kirk E. Jessup, Brock C. Blaser, Bob A. Stewart and Qingwu Xue

Agronomy 2022, 12(9), 2033; https://doi.org/10.3390/agronomy12092033 - 26 Aug 2022

Viewed by 1944

Abstract

Grain sorghum (Sorghum bicolor L.) is a major dryland crop in the Texas High Plains. Currently, drought and infestation by the sugarcane aphid (SCA, Melanaphis sacchari) are the two major challenges to grain sorghum production in the area. A 2-year field [...] Read more.

Grain sorghum (Sorghum bicolor L.) is a major dryland crop in the Texas High Plains. Currently, drought and infestation by the sugarcane aphid (SCA, Melanaphis sacchari) are the two major challenges to grain sorghum production in the area. A 2-year field study was conducted to investigate the effect of planting date (PD) and hybrid selection on yield, evapotranspiration (ET), water use efficiency (WUE), and SCA infestation. Five sorghum hybrids (86P20, SP-31A15, AG1201, AG1203, and DKS37-07) were grown on two planting dates (PD1—early May; PD2—late June) under dryland conditions. Insecticides were not used. There were significant differences in grain yield, WUE, evapotranspiration (ET), and SCA population between two PDs and among hybrids. For PD1, SCA infestation occurred after sorghum reached physiological maturity in 2017. Although SCA infestation was observed during late grain filling in 2018, SCA populations were low and did not affect yield. For PD2, SCA was present before anthesis in both years and significantly affected grain yield. Even with heavy SCA infestation in PD2, the grain yield was higher in PD2 than in PD1 due to timely precipitation. Among hybrids, AG1203, 86P20 and DK37-07 performed better with higher yield and less SCA infestation in PD2. Grain yield was more related to seeds per plant than to kernel weight and harvest index. Full article

(This article belongs to the Special Issue Maximizing Crop Yield and Resource Use Efficiency: Innovative Agronomic Practices)

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14 pages, 3102 KiB

Open AccessEditor’s ChoiceArticle

Pollen: A Potential Explant for Genetic Transformation in Wheat (Triticum aestivum L.)

by Mehwish Kanwal, Neelam Gogoi, Brian Jones, Harbans Bariana, Urmil Bansal and Nabil Ahmad

Agronomy 2022, 12(9), 2009; https://doi.org/10.3390/agronomy12092009 - 25 Aug 2022

Cited by 9 | Viewed by 3532

Abstract

The use of biotechnology for the genetic improvement of wheat (Triticum aestivum L.) has been hampered by its recalcitrance to standard transformation and regeneration protocols. Male gametes present a potentially useful option for introducing gene edits via clustered regularly interspaced short palindromic [...] Read more.

The use of biotechnology for the genetic improvement of wheat (Triticum aestivum L.) has been hampered by its recalcitrance to standard transformation and regeneration protocols. Male gametes present a potentially useful option for introducing gene edits via clustered regularly interspaced short palindromic repeats (CRISPR). However, the utility of male gametes for introducing genetic improvements would be dependent on the retention of viability after treatment to introduce the CRISPR components. We have studied wheat pollen morphology and its viability in a range of germination media to identify conditions that optimize the viability of in vitro hydrated pollen. The size, shape, and aperture from seven different wheat genotypes were compared using scanning electron microscope (SEM). The SEM results revealed that the pollen of all of the wheat genotypes examined in this study were monoporate; however, a significant variation in the size of the mature pollen grains was observed. The hydrated pollen of the wheat genotypes remained viable for up to five hours at 20 ± 2 °C. Of all of the germination media tested, the medium containing 5% sucrose, 10% PEG4000, 100 mg/L boric acid, 200 mg/L calcium nitrate, 100 mg/L potassium nitrate, and 100 mg/L magnesium sulphate at pH 6.5 achieved the highest percentage of pollen germination after 5 h of hydration. Impedance Flow Cytometry (IFC) provided similar results to the in vitro germination study. This work elucidates important factors that can form the basis for a pollen-based non-genetically modified system for gene editing in wheat. Full article

(This article belongs to the Special Issue Genetic Diversity and Population Structure in Crop and Woody Plants)

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13 pages, 592 KiB

Open AccessEditor’s ChoiceArticle

A Study of Application and Comparison of Thermal Drying and Freeze Drying of Fresh Edamame Seeds in the Analysis of Seed Composition

by Guo-Liang Jiang, William Townsend, Edward Sismour and Yixiang Xu

Agronomy 2022, 12(9), 1993; https://doi.org/10.3390/agronomy12091993 - 24 Aug 2022

Cited by 1 | Viewed by 2361

Abstract

Edamame is a vegetable soybean (Glycine max) with high nutritional and market value. It is mainly grown in Asia and has expanded to North America and Africa. Freeze and low- and high-heat drying methods were used to dry fresh edamame seeds [...] Read more.

Edamame is a vegetable soybean (Glycine max) with high nutritional and market value. It is mainly grown in Asia and has expanded to North America and Africa. Freeze and low- and high-heat drying methods were used to dry fresh edamame seeds of 20 soybean lines and cultivars for analysis of their composition using near-infrared reflectance (NIR) technology. The results indicated that significant differences existed between years of samplings for all seed composition traits investigated. Differences between drying methods were significant for all the traits with whole-seed samples, while they were not significant in protein, raffinose and linoleic acid for flour samples. Ground flour and whole-seed samples were similar or comparable in most cases for freeze and low-heat drying methods, but differences in seed composition between sample types were observed for high-heat drying. Among the traits investigated, protein content was the most consistent for all three drying methods, with an over 91% estimate of repeatability, showing high stability during drying. Oil content also showed a repeatability estimate of over 86% for all three drying methods. Low-heat drying generated results more comparable to freeze drying, while high-heat drying exhibited larger differences in most cases. Estimates of repeatability and correlation coefficients further confirmed that, low-heat drying, similar to freeze drying, was appropriate for drying fresh edamame seeds, but high-heat drying was not. Therefore, low-heat drying is a suitable method for drying fresh edamame and rapid analysis of seed composition, and it can be used as an alternative of freeze-drying method. Full article

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16 pages, 3999 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Increasing Agricultural Resilience through Combined Supply and Demand Management (Case Study: Karaj Reservoir Dam, Iran)

by Icen Yoosefdoost, Milad Basirifard, José Álvarez-García and María de la Cruz del Río-Rama

Agronomy 2022, 12(9), 1997; https://doi.org/10.3390/agronomy12091997 - 24 Aug 2022

Cited by 4 | Viewed by 8200

Abstract

Among the solutions to climate change’s harmful effects, AS (Adaptation Strategies) are more feasible. In this study, four AS, Changing Cultivation Dates (CCD), Deficit Irrigation (DI), Improving Irrigation Performance (IIP), and Optimizing the Crop Pattern (OCP), were investigated. The results showed that the [...] Read more.

Among the solutions to climate change’s harmful effects, AS (Adaptation Strategies) are more feasible. In this study, four AS, Changing Cultivation Dates (CCD), Deficit Irrigation (DI), Improving Irrigation Performance (IIP), and Optimizing the Crop Pattern (OCP), were investigated. The results showed that the WUE (Water Use Efficiency) was declined when the cultivation date was changed for all crops in the baseline and increased after the cultivation date was brought forward to 7, 14, 14, 28, 28 days for tomato, wheat, corn, barley and cucumber, respectively, in the future period. Deficit irrigation of 30% increased the WUE in all crops. A 48% increase in irrigation performance reduced demand by 10%. Following the OCP and diminishing the cultivation area by 30% increased farmers’ total profit and reduced the water consumption volume by 9% and 11%, respectively, in the baseline and future periods. To study the effect of these AS on crop yield and allocated volume, a combination of crop model programming and the MOEPO (Multi-Objective Emperor Penguin Optimizer) was employed to minimize Vulnerability and maximize Reliability Indexes (Performance Indexes). In the supply section, three scenarios were examined. The results showed that DI, IIP, CCD and OCP were classified from the most to the least option based on improving the Performance Indexes. Full article

(This article belongs to the Special Issue Water Use Efficiency for Resilient Economies: Innovative Experimental Approaches Based on the Soil Conditioners)

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20 pages, 4726 KiB

Open AccessEditor’s ChoiceArticle

Crop Load and Thinning Methods Impact Yield, Nutrient Content, Fruit Quality, and Physiological Disorders in ‘Scilate’ Apples

by Ramandeep Singh Sidhu, Sally A. Bound and Ian Hunt

Agronomy 2022, 12(9), 1989; https://doi.org/10.3390/agronomy12091989 - 23 Aug 2022

Cited by 20 | Viewed by 4291

Abstract

Most apple cultivars produce too many flowers to enable consistent yields of high-quality fruit, thus, crop load management (thinning) is an integral part of orchard management in modern apple cultivation. Crop load is managed by thinning excess flowers and/or fruit from a tree, [...] Read more.

Most apple cultivars produce too many flowers to enable consistent yields of high-quality fruit, thus, crop load management (thinning) is an integral part of orchard management in modern apple cultivation. Crop load is managed by thinning excess flowers and/or fruit from a tree, however ideal targets vary between cultivars. In this two-year study, the effect of thinning methods at different levels of crop load on fruit quality and production, post-harvest storability and physiological disorders, and fruit and leaf nutrient content in ‘Scilate’ apples were investigated in southern Tasmania, Australia. Two thinning methods, artificial bud extinction (ABE) and hand thinning (HT), were compared at three levels of crop load: 3, 6, or 12 fruit cm⁻² limb cross-sectional area (LCSA), described as low, medium, and high, respectively. During the second season, all the ABE and HT treatments received additional chemical thinning (CT). The results demonstrated that ABE consistently outperformed HT in terms of improved fruit set, return bloom, and fruit weight. The fruit quality parameters, such as flesh firmness, total soluble solids, dry matter content, malic acid content, and fruit shape, were also improved under the ABE regime, with these positive effects being the clearest in the second season. In general, high-quality fruits were obtained from the low and medium crop loads, while the fruit quality was poor for the high crop load trees, but the low crop load fruit had a slightly higher incidence of internal flesh browning (predominantly radial) and fruit softening after regular atmosphere storage. The crop load also impacted on the fruit and leaf mineral nutrient content, where fruit N, Ca, Mn, and Zn, and leaf N, Fe, Zn, and Cu content increased while fruit and leaf K declined with a higher crop load. High crop load, irrespective of the thinning regime, and HT with a medium crop load, induced severe biennial bearing, whereas, the fruit yield was relatively consistent with ABE, even with a medium crop load. We conclude that ABE with a medium crop load (around six fruit cm⁻² LCSA) is an effective method of managing crop load and optimizing the fruit quality in ‘Scilate’ apples. Full article

(This article belongs to the Special Issue Principles and Practices in Fruit Tree Production and Postharvest Management)

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11 pages, 5903 KiB

Open AccessEditor’s ChoiceArticle

Vernacular Names and Genetics of Cultivated Coffee (Coffea arabica) in Yemen

by Christophe Montagnon, Veronica Rossi, Carolina Guercio and Faris Sheibani

Agronomy 2022, 12(8), 1970; https://doi.org/10.3390/agronomy12081970 - 20 Aug 2022

Cited by 8 | Viewed by 6847

Abstract

While Ethiopia and South Sudan are the native habitats for Coffea arabica, Yemen is considered an important domestication center for this coffee species as most Arabica coffee grown around the world can be traced back to Yemen. Furthermore, climatic conditions in Yemen [...] Read more.

While Ethiopia and South Sudan are the native habitats for Coffea arabica, Yemen is considered an important domestication center for this coffee species as most Arabica coffee grown around the world can be traced back to Yemen. Furthermore, climatic conditions in Yemen are hot and extremely dry. As such, Yemeni coffee trees likely have genetic merits with respect to climate resilience. However, until recently, very little was known about the genetic landscape of Yemeni coffee. The Yemeni coffee sector identifies coffee trees according to numerous vernacular names such as Udaini, Tufahi or Dawairi. However, the geographical landscape of these names and their correlation with the genetic background of the coffee trees have never been explored. In this study, we investigated the geographic occurrence of vernacular names in 148 coffee farms across the main coffee areas of Yemen. Then, we used microsatellite markers to genotype 88 coffee trees whose vernacular name was ascertained by farmers. We find a clear geographical pattern for the use of vernacular coffee names. However, the vernacular names showed no significant association with genetics. Our results support the need for a robust description of different coffee types in Yemen based on their genetic background for the benefit of Yemeni farmers. Full article

(This article belongs to the Section Crop Breeding and Genetics)

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13 pages, 3486 KiB

Open AccessEditor’s ChoiceArticle

Tender Leaf Identification for Early-Spring Green Tea Based on Semi-Supervised Learning and Image Processing

by Jie Yang and Yong Chen

Agronomy 2022, 12(8), 1958; https://doi.org/10.3390/agronomy12081958 - 19 Aug 2022

Cited by 14 | Viewed by 3216

Abstract

Tea is one of the most common beverages in the world. Automated machinery that is suitable for plucking high-quality green tea is necessary for tea plantations and the identification of tender leaves is one of the key techniques. In this paper, we proposed [...] Read more.

Tea is one of the most common beverages in the world. Automated machinery that is suitable for plucking high-quality green tea is necessary for tea plantations and the identification of tender leaves is one of the key techniques. In this paper, we proposed a method that combines semi-supervised learning and image processing to identify tender leaves. Both in two-dimensional and three-dimensional space, the three R, G, and B components of tender leaves and their backgrounds were trained and tested. The gradient-descent method and the Adam algorithm were used to optimize the objective function, respectively. The results show that the average accuracy of tender leaf identification is 92.62% and the average misjudgment rate is 18.86%. Our experiments have shown that green tea tender leaves in early spring can be identified effectively using the model based on semi-supervised learning, which has strong versatility and perfect adaptability, so as to improve the problem of deep learning requiring a large number of labeled samples. Full article

(This article belongs to the Special Issue Advanced Technologies in Precision Processing and Modeling in Agriculture)

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17 pages, 1597 KiB

Open AccessEditor’s ChoiceArticle

Improvement of Photosynthetic Pigment Characteristics, Mineral Content, and Antioxidant Activity of Lettuce (Lactuca sativa L.) by Arbuscular Mycorrhizal Fungus and Seaweed Extract Foliar Application

by Mohammad Asadi, Farzad Rasouli, Trifa Amini, Mohammad Bagher Hassanpouraghdam, Somaye Souri, Sona Skrovankova, Jiri Mlcek and Sezai Ercisli

Agronomy 2022, 12(8), 1943; https://doi.org/10.3390/agronomy12081943 - 18 Aug 2022

Cited by 26 | Viewed by 3559

Abstract

Beneficial plant–microbe interaction for enhancing crop yield and quality is a sustainable way to achieve eco-friendly, desirable agricultural productions. The main objective of this experiment was to evaluate the individual and combined effects of an arbuscular mycorrhizal fungus (AMF) strain (Funneliformis mosseae [...] Read more.

Beneficial plant–microbe interaction for enhancing crop yield and quality is a sustainable way to achieve eco-friendly, desirable agricultural productions. The main objective of this experiment was to evaluate the individual and combined effects of an arbuscular mycorrhizal fungus (AMF) strain (Funneliformis mosseae) and a seaweed extract (SWE) derived from Ascophyllum nodosum, on the growth and physiological responses of lettuce (Lactuca sativa L.). Lettuce plants were inoculated with commercial AMF inoculum (5 g kg⁻¹ soil), and SWE foliar application was done at three levels (0.5, 1.5, and 3 g L⁻¹). The findings revealed that AMF along with SWE generated the greatest impact. In fact, co-application of AMF inoculation and 3 g L⁻¹ SWE considerably enhanced root colonization, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, and mineral content in the shoots and roots (N, P, K, Ca, Fe, Zn, and Mn content) of lettuce plants. This combination improved initial fluorescence (F₀), photochemical efficiency of PSII (F_V/F_m) and Y(NO) and total antioxidant activity (TAA), whereas the maximum fluorescence, (F_m) and Y(II), showed the highest increase in lettuce plants treated with AMF and 1.5 g L⁻¹ SWE. Furthermore, AMF inoculation along with SWE, at concentrations 1.5 and 3 g L⁻¹, considerably enhanced variable fluorescence (F_V) and the activity of water decomposition in electron donor photosystem II (F_V/F₀). As a result of these findings, it can be stated that the co-application of AMF and SWE positively improves the growth and development of lettuce plants. Full article

(This article belongs to the Special Issue Biofortification of Field Crops)

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17 pages, 2345 KiB

Open AccessEditor’s ChoiceArticle

Characterization of a Soybean (Glycine max L. Merr.) Population for Germination and Seedling Root Traits under Water Stress

by Jyoti Prasad Kakati, Benjamin Fallen, William Bridges and Sruthi Narayanan

Agronomy 2022, 12(8), 1944; https://doi.org/10.3390/agronomy12081944 - 18 Aug 2022

Cited by 4 | Viewed by 2641

Abstract

Dry soil conditions at soybean planting results in poor stand establishment, which often necessitates replanting. We conducted a study to identify soybean genotypes that can maintain germination rates and possess better root morphology under water stress. We tested 41 Plant Introductions (PI) for [...] Read more.

Dry soil conditions at soybean planting results in poor stand establishment, which often necessitates replanting. We conducted a study to identify soybean genotypes that can maintain germination rates and possess better root morphology under water stress. We tested 41 Plant Introductions (PI) for germination and seedling root traits under controlled environmental conditions at five water potentials: 0.00, −0.27, −0.54, −0.82, and −1.09 MPa (no, low, mild, severe, and extreme water stress, respectively). The same genotypes were tested for emergence and seedling root traits under field conditions in South Carolina (2021 and 2022) and North Carolina (2022). Among the 41 genotypes evaluated, PI 398566 and PI 424605A maintained higher germination percentages (≥63%) under water stress. The same genotypes were ranked among the top 15 genotypes for root traits (total-root and fine-root (diameter between 0.25 and 0.50 mm) length, surface area, and/or volume) under water stress. Furthermore, they had relatively higher emergence percentages under field conditions (≥35% under dry soil conditions). The superior genotypes identified in this study (PI 398566 and PI 424605A) that had better germination and root morphology under water-stress and no-stress conditions and better emergence would be useful for developing varieties with drought tolerance during the emergence phase. Full article

(This article belongs to the Special Issue Root Phenotypes of Plants in Different Growth Environment)

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13 pages, 716 KiB

Open AccessEditor’s ChoiceArticle

Exploring the Impact of the COVID-19 Pandemic on Firms’ Financial Performance and Cash Holding: New Evidence from China’s Agri-food Sector

by Jian Xu and Zhenji Jin

Agronomy 2022, 12(8), 1951; https://doi.org/10.3390/agronomy12081951 - 18 Aug 2022

Cited by 16 | Viewed by 4784

Abstract

The objective of this paper is to investigate the impact of coronavirus disease 2019 (COVID-19) on the financial performance and cash holdings of Chinese agri-food companies. We also examine whether or not company ownership, the affected areas, and leverage level affect this relationship. [...] Read more.

The objective of this paper is to investigate the impact of coronavirus disease 2019 (COVID-19) on the financial performance and cash holdings of Chinese agri-food companies. We also examine whether or not company ownership, the affected areas, and leverage level affect this relationship. The empirical results show that the COVID-19 outbreak has had no significant impact on financial performance and the cash-holding level of agri-food companies. In addition, the financial performance of state-owned companies is enhanced during such a crisis, whereas COVID-19 reduced the financial performance and cash-holding level of privately owned companies. In middle- and high-risk areas, the pandemic has had a negative impact on financial performance, while it has had a positive impact on financial performance in low-risk areas. The negative impact of COVID-19 on cash holding is greater in highly leveraged companies than it has been in low-leveraged companies. This paper may provide some new insights for managers to ensure smooth operation and improve firms’ performance in order to overcome this crisis. Full article

(This article belongs to the Special Issue COVID-19 Crises & Implications to Agri-Food Sector)

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16 pages, 1295 KiB

Open AccessEditor’s ChoiceArticle

Pyrolysis Temperature Affects Dissolved Phosphorus and Carbon Levels in Alkali-Enhanced Biochar and Its Soil Applications

by Meng Wang, Jim J. Wang, Jong-Hwan Park, Jian Wang, Xudong Wang, Zuoping Zhao, Fengmin Song and Bo Tang

Agronomy 2022, 12(8), 1923; https://doi.org/10.3390/agronomy12081923 - 15 Aug 2022

Cited by 7 | Viewed by 2623

Abstract

Alkali-enhanced biochars, as an environment-friendly material, combine the advantages of biomass nutrients and carbon fixation. In this study, rice-residue-derived biochars were evaluated for P and C solubility and their amendment upon plant P uptake. Biochars from rice straw (RS) and husk (RH), including [...] Read more.

Alkali-enhanced biochars, as an environment-friendly material, combine the advantages of biomass nutrients and carbon fixation. In this study, rice-residue-derived biochars were evaluated for P and C solubility and their amendment upon plant P uptake. Biochars from rice straw (RS) and husk (RH), including raw biochar without alkaline pretreatment (0B), alkali-enhanced biochars with KOH (5KB, 5 g KOH per 100 g feedstock;10KB, 10 g KOH per 100 g feedstock), K₂CO₃ (5K2B, 5 g K₂CO₃ per 100 g feedstock; 10K2B, 10 g K₂CO₃ per 100 g feedstock), and CaO (5CB, 5 g CaO per 100 g feedstock; 10CB,10 g CaO per 100 g feedstock) were prepared at 350 °C~550 °C pyrolysis conditions. Alkali-enhanced biochars on soil water soluble P(WSP) and C(WSC) levels were assessed through a soil-biochar incubation experiment. The effect of alkali-enhanced biochar on rice P uptake was evaluated in a greenhouse pot study. The WSP content in KOH- and K₂CO₃-enhanced biochars produced at 550 °C was significantly increased by up to 144% compared with that produced by the corresponding biochars at 350 °C, while the WSC content in all alkali-enhanced biochars (except for RS-5CB) prepared at 550 °C significantly decreased by up to 6426% compared with that produced by the corresponding biochars at 350 °C. The application of 3% 10KB and 10K2B rice straw biochars (produced at 550 °C) significantly elevated the WSP content in soils. Rice grown in the RH-10K2B-550 treated soil significantly increased the grain P uptake by 15% and 8% compared with RH-0B-350 and RH-10K2B-350, respectively. The water soluble P of the KOH- and K₂CO₃-enhanced biochars increased with increasing the pyrolysis temperature. RS-10KB and RS-10K2B increased the soil WSP and WSC content compared with the unenhanced biochar (RS-0B), and showed a clear positive effect on increasing the rice P uptake. Overall, KOH- and K₂CO₃-enhanced biochars pyrolyzed at 550 °C as Si sources could also serve as a potential P pool with multi-functions in C sequestration and K nutrition. Full article

(This article belongs to the Topic Advances in Sustainable Agri-Food Systems: Insights into Production, Processing, and Consumption Perspectives)

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14 pages, 764 KiB

Open AccessEditor’s ChoiceArticle

Strategies to Reduce Radiation Stress in Open-Field Ginger and Turmeric Production

by Marlon Retana-Cordero, Sofia Flores, Rosanna Freyre and Celina Gómez

Agronomy 2022, 12(8), 1910; https://doi.org/10.3390/agronomy12081910 - 14 Aug 2022

Cited by 1 | Viewed by 2739

Abstract

Excess solar radiation can negatively affect growth and rhizome yield of ginger (Zingiber officinale) and turmeric (Curcuma longa) plants. Thus, the objective of this study was to evaluate the effect of 60% shade nets (Experiment 1) as well as [...] Read more.

Excess solar radiation can negatively affect growth and rhizome yield of ginger (Zingiber officinale) and turmeric (Curcuma longa) plants. Thus, the objective of this study was to evaluate the effect of 60% shade nets (Experiment 1) as well as white and red kaolin sprays during two production stages (early establishment vs. entire cycle) (Experiment 2) on field-grown ginger and turmeric plants. In Experiment 1, plants were propagated from seed rhizomes (R) or second-generation rhizomes from tissue-cultured plants (2GR), while only R were used in Experiment 2. There were no differences in rhizome yield in response to shade in Experiment 1, with mean values of 644 and 692 g in ginger and turmeric, respectively. Overall, 2GR ginger plants produced a higher rhizome yield (880 g) than R plants (425 g), but no yield differences were measured in turmeric. In Experiment 2, for both species and regardless of kaolin color, sprays applied during the entire cycle increased photosynthesis and stomatal conductance and reduced leaf temperature and transpiration compared to control. Rhizome yield was also up to 87% higher in ginger and 47% higher in turmeric plants sprayed with kaolin. Spraying plants with white kaolin during the early season establishment of these crops can be an effective strategy to reduce radiation stress for open-field production. Full article

(This article belongs to the Special Issue Innovations in Tropical Vegetable Agroecosystems)

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18 pages, 3192 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Association Study for Abscission Failure of Fruit Pericarps (Stick-Tights) in Wild Macadamia Germplasm

by Jasmine Nunn, Joanne De Faveri, Katie O’Connor, Mobashwer Alam, Craig Hardner, Olufemi Akinsanmi and Bruce Topp

Agronomy 2022, 12(8), 1913; https://doi.org/10.3390/agronomy12081913 - 14 Aug 2022

Cited by 5 | Viewed by 2023

Abstract

Macadamia pericarps that fail to abscise (‘stick-tights’) are an important trait to select against in breeding as they can harbour pests and diseases. Traditional macadamia breeding cycles are lengthy and expensive due to long juvenilities and large tree sizes. Thus, genome-wide association studies [...] Read more.

Macadamia pericarps that fail to abscise (‘stick-tights’) are an important trait to select against in breeding as they can harbour pests and diseases. Traditional macadamia breeding cycles are lengthy and expensive due to long juvenilities and large tree sizes. Thus, genome-wide association studies (GWAS) are an important investigative tool to identify candidate trait-linked markers to enable potential reductions in evaluation and selection cycles via marker-assisted selection (MAS) in young seedlings. This study assessed 199 wild macadamia germplasm accessions for stick-tight prevalence across two years. As the number of stick-tights per tree is limited by the number of nuts per tree, we conducted association analyses to identify SNPs linked with the number of stick-tights per tree, and examined whether such SNPs were also associated with, and thus confounded with, the number of nuts per tree. We also assessed associations with the proportion of stick-tights per total number of nuts. Thirty-two SNPs were associated with at least one of the stick-tight traits in one year (p < 0.001). Of all such SNPs, only one was associated with the number of nuts per tree (p < 0.001), indicating that most associations were not confounded with yield. Full article

(This article belongs to the Special Issue DNA-Informed Breeding in Fruit and Nut Crops)

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14 pages, 916 KiB

Open AccessEditor’s ChoiceArticle

Effect of Regulated Deficit Irrigation on the Quality of ‘Arbequina’ Extra Virgin Olive Oil Produced on a Super-High-Intensive Orchard

by José Miguel García-Garví, Paola Sánchez-Bravo, Francisca Hernández, Esther Sendra, Mireia Corell, Alfonso Moriana, Armando Burgos-Hernández and Ángel A. Carbonell-Barrachina

Agronomy 2022, 12(8), 1892; https://doi.org/10.3390/agronomy12081892 - 12 Aug 2022

Cited by 14 | Viewed by 2738

Abstract

The expansion of the super-high-intensive cultivation of olive groves requires irrigation techniques that are compatible with the increasing scarcity of water due to climate change and olive oil demand. For this, the effect of two regulated deficit irrigation treatments (RDI) and a sustained [...] Read more.

The expansion of the super-high-intensive cultivation of olive groves requires irrigation techniques that are compatible with the increasing scarcity of water due to climate change and olive oil demand. For this, the effect of two regulated deficit irrigation treatments (RDI) and a sustained deficit irrigation (SDI) treatment was studied. The treatments consisted of: (i) control treatment, which supplied 100% of the water lost by evapotranspiration (ET₀); (ii) the “optimal RDI” treatment, which only reduced irrigation water (~37–54% reduction) during the pit hardening stage; (iii) the “confederation RDI” which limited water restriction to the donation of the Guadalquivir hydrographic confederation (~72% reduction); and, (iv) the “confederation SDI”, similar water restriction (~72%) but dying the whole tree cycle. In general, the reduction in the irrigation water caused no negative effects on the studied parameters. However, the total phenolic content (TPC) was increased when the deficit irrigation was applied. Fatty acid profile showed changes with respect to the control, increasing oleic acid and the total content of monounsaturated fatty acids (MUFA). For the volatile compound profile, reducing water intake caused changes in mayor volatile compound (trans-2-hexenal), related with green flavors. The application of deficit irrigation treatments increased the value obtained in the fruity parameter with respect to the control. On the other hand, irrigation deficit treatments did not generate changes in the olive oil yield. Full article

(This article belongs to the Special Issue Water Scarcity Management in Fruit Orchards: Potential Benefits on Fruit Quality and Long-Term Orchards Conservation)

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17 pages, 2375 KiB

Open AccessEditor’s ChoiceArticle

Analysis of Biophysical Variables in an Onion Crop (Allium cepa L.) with Nitrogen Fertilization by Sentinel-2 Observations

by Alejandra Casella, Luciano Orden, Néstor A. Pezzola, Carolina Bellaccomo, Cristina I. Winschel, Gabriel R. Caballero, Jesús Delegido, Luis Manuel Navas Gracia and Jochem Verrelst

Agronomy 2022, 12(8), 1884; https://doi.org/10.3390/agronomy12081884 - 11 Aug 2022

Cited by 9 | Viewed by 3651

Abstract

The production of onions bulbs (Allium cepa L.) requires a high amount of nitrogen. According to the demand of sustainable agriculture, the information-development and communication technologies allow for improving the efficiency of nitrogen fertilization. In the south of the province of Buenos [...] Read more.

The production of onions bulbs (Allium cepa L.) requires a high amount of nitrogen. According to the demand of sustainable agriculture, the information-development and communication technologies allow for improving the efficiency of nitrogen fertilization. In the south of the province of Buenos Aires, Argentina, between 8000 and 10,000 hectares per year⁻¹ are cultivated in the districts of Villarino and Patagones. This work aimed to analyze the relationship of biophysical variables: leaf area index (LAI), canopy chlorophyll content (CCC), and canopy cover factor (fCOVER), with the nitrogen fertilization of an intermediate cycle onion crop and its effects on yield. A field trial study with different doses of granulated urea and granulated urea was carried out, where biophysical characteristics were evaluated in the field and in Sentinel-2 satellite observations. Field data correlated well with satellite data, with an R² of 0.91, 0.96, and 0.85 for LAI, fCOVER, and CCC, respectively. The application of nitrogen in all its doses produced significantly higher yields than the control. The LAI and CCC variables had a positive correlation with yield in the months of November and December. A significant difference was observed between U250 (62 Mg ha⁻¹) and the other treatments. The U500 dose led to a yield increase of 27% compared to U250, while the difference between U750 and U500 was 6%. Full article

(This article belongs to the Special Issue Selected Papers from 11th Iberian Agroengineering Congress)

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16 pages, 2768 KiB

Open AccessEditor’s ChoiceArticle

Estimation of Fusarium Head Blight Severity Based on Transfer Learning

by Chunfeng Gao, Zheng Gong, Xingjie Ji, Mengjia Dang, Qiang He, Heguang Sun and Wei Guo

Agronomy 2022, 12(8), 1876; https://doi.org/10.3390/agronomy12081876 - 10 Aug 2022

Cited by 14 | Viewed by 2418

Abstract

The recognition accuracy of traditional image recognition methods is heavily dependent on the design of complicated and tedious hand-crafted features. In view of the problems of poor accuracy and complicated feature extraction, this study presents a methodology for the estimation of the severity [...] Read more.

The recognition accuracy of traditional image recognition methods is heavily dependent on the design of complicated and tedious hand-crafted features. In view of the problems of poor accuracy and complicated feature extraction, this study presents a methodology for the estimation of the severity of wheat Fusarium head blight (FHB) with a small sample dataset based on transfer learning technology and convolutional neural networks (CNNs). Firstly, we utilized the potent feature learning and feature expression capabilities of CNNs to realize the automatic learning of FHB characteristics. Using transfer learning technology, VGG16, ResNet50, and MobileNetV1 models were pre-trained on the ImageNet. The knowledge was transferred to the estimation of FHB severity, and the fully connected (FC) layer of the models was modified. Secondly, acquiring the wheat images at the peak of the outbreak of FHB as the research object, after preprocessing for size filling on the wheat images, the image dataset was expanded with operations such as mirror flip, rotation transformation, and superimposed noise to improve the performance of the model and reduce the overfitting of models. Finally, under the Tensorflow deep learning framework, the VGG16, ResNet50, and MobileNetV1 models were subjected to transfer learning. The results showed that in the case of transfer learning and data augmentation, the ResNet50 model in Accuracy, Precision, Recall, and F1 score was better than the other two models, giving the highest accuracy of 98.42% and F1 score of 97.86%. The ResNet50 model had the highest recognition accuracy, providing technical support and reference for the accurate recognition of FHB. Full article

(This article belongs to the Special Issue Applications of Deep Learning Techniques in Agronomy)

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25 pages, 8511 KiB

Open AccessEditor’s ChoiceArticle

Evaluating Plant Disease Detection Mobile Applications: Quality and Limitations

by Ayesha Siddiqua, Muhammad Ashad Kabir, Tanzina Ferdous, Israt Bintea Ali and Leslie A. Weston

Agronomy 2022, 12(8), 1869; https://doi.org/10.3390/agronomy12081869 - 8 Aug 2022

Cited by 36 | Viewed by 25680

Abstract

In this technologically advanced era, with the proliferation of artificial intelligence, many mobile apps are available for plant disease detection, diagnosis, and treatment, each with a variety of features. These apps need to be categorized and reviewed following a proper framework that ensures [...] Read more.

In this technologically advanced era, with the proliferation of artificial intelligence, many mobile apps are available for plant disease detection, diagnosis, and treatment, each with a variety of features. These apps need to be categorized and reviewed following a proper framework that ensures their quality. This study aims to present an approach to evaluating plant disease detection mobile apps, which includes providing ratings of distinct features of the apps and insights into the exploitation of artificial intelligence used in plant disease detection. The applicability of these apps for pathogen or disease detection, identification, and treatment will be assessed along with significant insights garnered. For this purpose, plant disease detection apps were searched in three prominent app stores (the Google Play store, Apple App store, and Microsoft store) using a set of keywords. A total of 606 apps were found and from them, 17 relevant apps were identified based on inclusion and exclusion criteria. The selected apps were reviewed by three raters using our devised app rating scale. To validate the rater agreements on the ratings, inter-rater reliability is computed alongside their intra-rater reliability, ensuring their rating consistency. Also, the internal consistency of our rating scale was evaluated against all selected apps. User comments from the app stores are collected and analyzed to understand their expectations and views. Following the rating procedure, most apps earned acceptable ratings in software quality characteristics such as aesthetics, usability, and performance but gained poor ratings in AI-based advanced functionality, which is the key aspect of this study. However, most of the apps cannot be used as a complete solution to plant disease detection, diagnosis, and treatment. Only one app, Plantix–your crop doctor, could successfully identify plants from images, detect diseases, maintain a rich plant database, and suggest potential treatments for the disease presented. It also provides a community where plant lovers can communicate with each other to gain additional benefits. In general, all existing apps need to improve functionalities, user experience, and software quality. Therefore, a set of design considerations has been proposed for future app improvements. Full article

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13 pages, 779 KiB

Open AccessEditor’s ChoiceArticle

Temperature and Soil Moisture Drive Coumestrol Concentration in Annual Medicago spp. in the Presence but Not Absence of Phoma Black Stem and Leaf Spot (Phoma medicaginis)

by Mahtab Omidvari, Gavin R. Flematti, Ming Pei You, Payman Abbaszadeh-Dahaji and Martin J. Barbetti

Agronomy 2022, 12(8), 1863; https://doi.org/10.3390/agronomy12081863 - 7 Aug 2022

Cited by 2 | Viewed by 1912

Abstract

Studies were undertaken to determine the impact of environmental variables temperature (12.5/9.5, 20/17, 27/24 °C day/night) and soil moisture (100, 50% WHC), and their interaction with Phoma medicaginis infection, on production of the phytoestrogen coumestrol in annual Medicago rugosa cv. Paraponto and M. [...] Read more.

Studies were undertaken to determine the impact of environmental variables temperature (12.5/9.5, 20/17, 27/24 °C day/night) and soil moisture (100, 50% WHC), and their interaction with Phoma medicaginis infection, on production of the phytoestrogen coumestrol in annual Medicago rugosa cv. Paraponto and M. scutellata cv. Sava. Disease factors measured included leaf disease incidence/severity, petiole/stem disease incidence/severity, and leaf yellowing severity. Coumestrol levels were determined using gas chromatography–mass spectrometry (GC–MS). Increasing temperature from 12.5/9.5 °C to 27/24 °C in inoculated plants significantly (p < 0.05) increased coumestrol from 193 mg kg⁻¹ to 390 mg kg⁻¹, but there were no differences in coumestrol production across all three temperatures in uninoculated plants. Reducing soil moisture from 100% to 50% WHC at the highest temperature (27/24 °C) caused the greatest increase in coumestrol production from 156 to 269 mg kg⁻¹ in inoculated plants. The greatest coumestrol production (600 mg kg⁻¹) was under 27/24 °C/50% WHC for Sava infected with P. medicaginis and least coumestrol (1.6 mg kg⁻¹) was Sava under 20/17 °C/50% WHC in the absence of P. medicaginis. Clearly, situations of higher temperatures in conjunction with lower soil moisture levels cause greatest elevation in coumestrol in the presence of P. medicaginis, levels far exceeding the animal risk threshold of 25 mg kg⁻¹. Full article

(This article belongs to the Section Pest and Disease Management)

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21 pages, 4337 KiB

Open AccessEditor’s ChoiceArticle

Exogenously Applied Salicylic Acid Boosts Morpho-Physiological Traits, Yield, and Water Productivity of Lowland Rice under Normal and Deficit Irrigation

by Heba Abdelhamid El Sherbiny, Essam F. El-Hashash, Moamen M. Abou El-Enin, Randa Samir Nofal, Taia A. Abd El-Mageed, Eman Mohamed Bleih, Mohamed T. El-Saadony, Khaled A. El-Tarabily and Ahmed Shaaban

Agronomy 2022, 12(8), 1860; https://doi.org/10.3390/agronomy12081860 - 6 Aug 2022

Cited by 17 | Viewed by 3181

Abstract

The main constraint on rice cultivation in the Mediterranean area is the limited irrigation and its large water consumption. In addition, rice is very sensitive to drought conditions because of drought stress on morpho-physiological traits and yield reduction. The application of salicylic acid [...] Read more.

The main constraint on rice cultivation in the Mediterranean area is the limited irrigation and its large water consumption. In addition, rice is very sensitive to drought conditions because of drought stress on morpho-physiological traits and yield reduction. The application of salicylic acid (SA) has been noticed to be very effective in alleviating the adverse effects of drought stress on rice. The current investigation was conducted as a split-split arrangement under a randomized complete block design with two lowland rice cultivars (Giza177 and Giza179) and SA as a foliar application at four concentrations (0, 400, 700, and 1000 µM) under normal and drought conditions. The results showed that plant growth, leaf photosynthetic pigments, yields, and the most studied traits were significantly affected by irrigation (I), cultivar (C), and SA concentration (p ≤ 0.05 or 0.01). The interaction effect of I × C × SA was only significant on the carotenoids content (p ≤ 0.05). The reduction in grain yield and most studied traits was more pronounced under drought conditions. The Giza179 proved to be a drought-tolerant cultivar under all SA concentrations under drought conditions, while Giza177 was a drought-sensitive cultivar. The application of 700 µM SA gave the best grain yield in both rice cultivars under drought conditions compared to other SA concentrations. Grain yield for normal irrigation (Yp) and drought stress (Ys) conditions were highly positively correlated with indices of the mean productivity (MP), geometric mean productivity (GMP), stress tolerance index (STI), yield index (YI), yield stability index (YSI), drought resistance index (DI), harmonic mean (HM), and golden mean (GOL). While they are highly negatively correlated with the indices of the stress susceptibility index (SSI), tolerance index (TOL), yield reduction ratio (YR), stress susceptibility percentage index (SSPI), and abiotic tolerance index (ATI). It could be concluded that SA, as a growth regulator, could be used to alleviate the harmful effect of inadequate water availability in soil on rice cultivars as well as to improve the growth, water productivity, and grain yield. Full article

(This article belongs to the Special Issue Rice Based Cropping Systems: Technological Interventions for Improving System Productivity and Profitability)

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18 pages, 616 KiB

Open AccessEditor’s ChoiceArticle

Evaluating Chemical Suppression Treatments to Alter the Red: Far-Red Ratio in Perennial Groundcovers for Maize Production

by Cynthia A. Bartel, Kenneth J. Moore, Shui-zhang Fei, Andrew W. Lenssen, Roger L. Hintz and Samantha M. Kling

Agronomy 2022, 12(8), 1854; https://doi.org/10.3390/agronomy12081854 - 5 Aug 2022

Cited by 2 | Viewed by 2477

Abstract

Perennial groundcover (PGC) has great potential to deliver ecosystem service benefits and control weeds in annual row crop systems. Inadequately suppressed PGC, however, acts as an early-season weed, causing a shade avoidance response (SAR) in maize (Zea mays L.) before the critical [...] Read more.

Perennial groundcover (PGC) has great potential to deliver ecosystem service benefits and control weeds in annual row crop systems. Inadequately suppressed PGC, however, acts as an early-season weed, causing a shade avoidance response (SAR) in maize (Zea mays L.) before the critical period for weed control (CPWC) even with resource abundance. The SAR results from a low red to far-red light shift, impairing early season plant growth and decreasing yield. A field study was conducted in Ames, IA, USA to assess application timing of groundcover suppression chemicals on maize growth and development. Two suppression chemical treatments (paraquat or paraquat + glufosinate) were each applied to “Midnight” Kentucky bluegrass (Poa pratensis L.) PGC once on the day of maize planting (DOP) or consecutive maize stages from VE to V6 in a randomized complete block design with unsuppressed groundcover control. Response variables included maize plant height, maize phenological development stage, reflected red:far-red (R:FR) ratio above the PGC canopy, early vegetative and final maize plant density, maize yield and components, and weed communities. Suppression increased reflected R:FR ratio from the groundcover immediately after application. Where suppression was applied at later stages, low R:FR ratio during early vegetative growth stages triggered a maize SAR and maize plant etiolation. Final maize plant height and yield were greater in PGC suppressed at earlier maize stages, although no suppression treatment provided adequate suppression duration. Paraquat + glufosinate more effectively suppressed groundcover overall and limited groundcover competition, producing 8% greater maize grain yield than paraquat alone in year 1, and 13% greater stover and 8% greater total aboveground biomass (TAB) in year 2. Weather conditions influenced chemical suppression efficacy in year 2, emphasizing the importance of identifying reliable chemical suppression to support grain yield from the day of maize planting. Full article

(This article belongs to the Section Innovative Cropping Systems)

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16 pages, 2841 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Transplant Date and Plant Spacing on Biomass Production for Floral Hemp (Cannabis sativa L.)

by Eric R. Linder, Sierra Young, Xu Li, Shannon Henriquez Inoa and David H Suchoff

Agronomy 2022, 12(8), 1856; https://doi.org/10.3390/agronomy12081856 - 5 Aug 2022

Cited by 11 | Viewed by 4992

Abstract

Floral hemp cultivated for the extraction of cannabinoids is a new crop in the United States, and agronomic recommendations are scarce. The objective of this study was to understand the effects of plant spacing and transplant date on floral hemp growth and biomass [...] Read more.

Floral hemp cultivated for the extraction of cannabinoids is a new crop in the United States, and agronomic recommendations are scarce. The objective of this study was to understand the effects of plant spacing and transplant date on floral hemp growth and biomass production. Field trials were conducted in North Carolina in 2020 and 2021 with the floral hemp cultivar BaOx. Transplant date treatments occurred every two weeks from 11 May to 7 July (±1 d). Plant spacing treatments were 0.91, 1.22, 1.52, and 1.83 m between plants. Weekly height and width data were collected throughout the vegetative period, and dry biomass was measured at harvest. Plant width was affected by transplant date and spacing. Plant height was affected by transplant date. Earlier transplant dates resulted in taller, wider plants, while larger plant spacing resulted in wider plants. Individual plant biomass increased with earlier transplant dates and larger plant spacing. On a per-hectare basis, biomass increased with earlier transplant dates and smaller transplant spacing. An economic analysis found that returns were highest with 1.22 m spacing and decreased linearly by a rate of −163.098 USD ha⁻¹ d⁻¹. These findings highlight the importance of earlier transplant timing to maximize harvestable biomass. Full article

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20 pages, 5528 KiB

Open AccessEditor’s ChoiceArticle

Development of Deep Learning Methodology for Maize Seed Variety Recognition Based on Improved Swin Transformer

by Chunguang Bi, Nan Hu, Yiqiang Zou, Shuo Zhang, Suzhen Xu and Helong Yu

Agronomy 2022, 12(8), 1843; https://doi.org/10.3390/agronomy12081843 - 4 Aug 2022

Cited by 50 | Viewed by 4892

Abstract

In order to solve the problems of high subjectivity, frequent error occurrence and easy damage of traditional corn seed identification methods, this paper combines deep learning with machine vision and the utilization of the basis of the Swin Transformer to improve maize seed [...] Read more.

In order to solve the problems of high subjectivity, frequent error occurrence and easy damage of traditional corn seed identification methods, this paper combines deep learning with machine vision and the utilization of the basis of the Swin Transformer to improve maize seed recognition. The study was focused on feature attention and multi-scale feature fusion learning. Firstly, input the seed image into the network to obtain shallow features and deep features; secondly, a feature attention layer was introduced to give weights to different stages of features to strengthen and suppress; and finally, the shallow features and deep features were fused to construct multi-scale fusion features of corn seed images, and the seed images are divided into 19 varieties through a classifier. The experimental results showed that the average precision, recall and F1 values of the MFSwin Transformer model on the test set were 96.53%, 96.46%, and 96.47%, respectively, and the parameter memory is 12.83 M. Compared to other models, the MFSwin Transformer model achieved the highest classification accuracy results. Therefore, the neural network proposed in this paper can classify corn seeds accurately and efficiently, could meet the high-precision classification requirements of corn seed images, and provide a reference tool for seed identification. Full article

(This article belongs to the Special Issue “Smart Agriculture” Information Technology and Agriculture Cross-Discipline Research and Development)

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14 pages, 3178 KiB

Open AccessEditor’s ChoiceArticle

Emissions of Greenhouse Gases and NO from Rice Fields and a Peach Orchard as Affected by N Input and Land-Use Conversion

by Pinshang Xu, Zhaoqiang Han, Jie Wu, Zhutao Li, Jinyang Wang and Jianwen Zou

Agronomy 2022, 12(8), 1850; https://doi.org/10.3390/agronomy12081850 - 4 Aug 2022

Cited by 10 | Viewed by 3408

Abstract

Nitrogen (N) inputs and land-use conversion are management practices that affect soil greenhouse gas (GHG) and nitric oxide (NO) emissions. Here, we measured soil methane (CH₄), nitrous oxide (N₂O), and NO fluxes from rice fields and a peach orchard [...] Read more.

Nitrogen (N) inputs and land-use conversion are management practices that affect soil greenhouse gas (GHG) and nitric oxide (NO) emissions. Here, we measured soil methane (CH₄), nitrous oxide (N₂O), and NO fluxes from rice fields and a peach orchard that converted from paddies to assess the impacts of nitrogen (N) inputs and land-use conversion on their emissions. Treatments included four paddy field treatments (PN0, PN160, PN220, and PN280) and one peach orchard treatment (ON280) with number indicating the N-input rate of kg N ha⁻¹. The results showed that cumulative emissions of CH₄, N₂O and NO ranged from 28.6 to 85.3 kg C ha⁻¹, 0.5 to 4.0 kg N ha⁻¹ and 0.2 to 0.3 kg N ha⁻¹ during the rice-growing season, respectively. In terms of greenhouse gas intensity, the PN280 treatment is the recommended N application rate. Land-use conversion significantly reduced the global warming potential from croplands. The conversion shifted soils from an essential source of CH₄ to a small net sink. In addition, N₂O emissions from the rice–wheat rotation system were 1.8 times higher than from the orchard, mainly due to the difference in the N application rate. In summary, to reduce agriculture-induced GHG emissions, future research needs to focus on the effects of N inputs on rice-upland crop rotation systems. Full article

(This article belongs to the Special Issue Low Carbon Agriculture and Low Reactive Nitrogen Losses under Intensification)

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