Agronomy

Article

14 pages, 4142 KiB

Open AccessEditor’s ChoiceArticle

Data-Driven Artificial Intelligence Applications for Sustainable Precision Agriculture

by Maria Teresa Linaza, Jorge Posada, Jürgen Bund, Peter Eisert, Marco Quartulli, Jürgen Döllner, Alain Pagani, Igor G. Olaizola, Andre Barriguinha, Theocharis Moysiadis and Laurent Lucat

Agronomy 2021, 11(6), 1227; https://doi.org/10.3390/agronomy11061227 - 17 Jun 2021

Cited by 160 | Viewed by 18518

Abstract

One of the main challenges for the implementation of artificial intelligence (AI) in agriculture includes the low replicability and the corresponding difficulty in systematic data gathering, as no two fields are exactly alike. Therefore, the comparison of several pilot experiments in different fields, [...] Read more.

One of the main challenges for the implementation of artificial intelligence (AI) in agriculture includes the low replicability and the corresponding difficulty in systematic data gathering, as no two fields are exactly alike. Therefore, the comparison of several pilot experiments in different fields, weather conditions and farming techniques enhances the collective knowledge. Thus, this work provides a summary of the most recent research activities in the form of research projects implemented and validated by the authors in several European countries, with the objective of presenting the already achieved results, the current investigations and the still open technical challenges. As an overall conclusion, it can be mentioned that even though in their primary stages in some cases, AI technologies improve decision support at farm level, monitoring conditions and optimizing production to allow farmers to apply the optimal number of inputs for each crop, thereby boosting yields and reducing water use and greenhouse gas emissions. Future extensions of this work will include new concepts based on autonomous and intelligent robots for plant and soil sample retrieval, and effective livestock management. Full article

(This article belongs to the Special Issue Data-Driven Agricultural Innovations)

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13 pages, 3127 KiB

Open AccessEditor’s ChoiceArticle

Integrated Nutrient Management Significantly Improves Pomelo (Citrus grandis) Root Growth and Nutrients Uptake under Acidic Soil of Southern China

by Xiaoman Huang, Muhammad Atif Muneer, Jian Li, Wei Hou, Changcheng Ma, Jiabin Jiao, Yuanyang Cai, Xiaohui Chen, Liangquan Wu and Chaoyuan Zheng

Agronomy 2021, 11(6), 1231; https://doi.org/10.3390/agronomy11061231 - 17 Jun 2021

Cited by 28 | Viewed by 5404

Abstract

Root system plays a crucial role in plant growth and development by uptake of soil nutrients, which is affected by intensive use of NPK fertilizer. However, it is unknown how integrated nutrient management (INM) could affect the root growth and its nutrient uptake [...] Read more.

Root system plays a crucial role in plant growth and development by uptake of soil nutrients, which is affected by intensive use of NPK fertilizer. However, it is unknown how integrated nutrient management (INM) could affect the root growth and its nutrient uptake in the red soils of southern China. For this, the impacts of different INM practices on root morphological traits and root nutrient uptake were investigated in the pomelo tree. First, we investigated the spatial root distribution of various tree ages (i.e., 8, 13, 18, and 23 years old) and found the optimum root growth at 20–80 cm around the tree trunk in topsoil (0–20 cm). Hence, the pomelo trees were fertilized at 20–80 cm around the trunk, i.e., FFP (farmer fertilization practice), optimization NPK fertilizer (O) combined with lime (L) and mushroom residue (M) known as O+L+M treatment, and O+L combined with Mg fertilizer called as O+L+Mg treatment. We found that root length (RL) significantly increased by application of O+L+M (108.5 and 219.1 cm) and O+L+Mg (73.6, 66.8 cm) in topsoil and subsoil, respectively, in 2019. Similarly, root surface area (RSA) was significantly higher under INM, i.e., O+L+Mg > O+L+M > FFP. For root diameter (RD), O+L+M (0.8 mm) and O+L+Mg (1.5 mm) showed significantly lower diameter than FFP (2.54 mm). The root tips (RT) also improved considerably under INM practices compared with FFP. Besides, root nutrient contents (N, P, K, Ca, and Mg) also significantly improved under O+L+M and O+L+Mg over FFP. Similar trends of root growth and nutrients uptake were recorded in 2020. Overall, these findings suggest that INM plays a significant role in root development and nutrient uptake under acidic soil, which could be useful for maximizing crop productivity. Full article

(This article belongs to the Special Issue Effects of Compost Fertilizer on the Vegetative and Productive Performance of the Tree Plants)

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14 pages, 2350 KiB

Open AccessEditor’s ChoiceArticle

Modelled Quantification of Different Sources of Nitrogen Inefficiency in Semi-Arid Cropping Systems

by Niloufar Nasrollahi, James Hunt, Caixian Tang and David Cann

Agronomy 2021, 11(6), 1222; https://doi.org/10.3390/agronomy11061222 - 16 Jun 2021

Cited by 3 | Viewed by 2817

Abstract

Most dryland grain growers in Australia retain all or most of their crop residues to protect the soil from erosion and to improve water conservation but retaining stubbles with a high carbon-to-nitrogen (C:N) ratio can affect N availability to crops. A simulation experiment [...] Read more.

Most dryland grain growers in Australia retain all or most of their crop residues to protect the soil from erosion and to improve water conservation but retaining stubbles with a high carbon-to-nitrogen (C:N) ratio can affect N availability to crops. A simulation experiment was conducted to investigate the effects of N fertilizer application rate and residue retention on soil N dynamics. The simulation used seven N fertilizer application rates (0, 25, 50, 75, 100, 150 and 200 kg N ha⁻¹) to wheat (Triticum aestivum) over 27 years (1990–2016) at four locations across a gradient in annual rainfall in Victoria, Australia. Nitrogen immobilization, denitrification and N leaching loss were predicted and collectively defined as sources of N inefficiency. When residues were retained, immobilization was predicted to be the biggest source of inefficiency at all simulated sites at N application rates currently used by growers. Leaching became a bigger source of inefficiency at one site with low soil water-holding capacity, but only at N rates much higher than would currently be commercially applied, resulting in high levels of nitrate (NO₃⁻) accumulating in the soil. Denitrification was an appreciable source of inefficiency at higher rainfall sites. Further research is necessary to evaluate strategies to minimize immobilization of N in semi-arid cropping systems. Full article

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

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19 pages, 6629 KiB

Open AccessEditor’s ChoiceArticle

A Field-Tested Harvesting Robot for Oyster Mushroom in Greenhouse

by Jiacheng Rong, Pengbo Wang, Qian Yang and Feng Huang

Agronomy 2021, 11(6), 1210; https://doi.org/10.3390/agronomy11061210 - 15 Jun 2021

Cited by 55 | Viewed by 8155

Abstract

The fully autonomous harvesting of oyster mushrooms in the greenhouse requires the development of a reliable and robust harvesting robot. In this paper, we propose an oyster-mushroom-harvesting robot, which can realize harvesting operations in the entire greenhouse. The two crucial components of the [...] Read more.

The fully autonomous harvesting of oyster mushrooms in the greenhouse requires the development of a reliable and robust harvesting robot. In this paper, we propose an oyster-mushroom-harvesting robot, which can realize harvesting operations in the entire greenhouse. The two crucial components of the harvesting robot are the perception module and the end-effector. Intel RealSense D435i is adopted to collect RGB images and point cloud images in real time; an improved SSD algorithm is proposed to detect mushrooms, and finally, the existing soft gripper is manipulated to grasp oyster mushrooms. Field experiments exhibit the feasibility and robustness of the proposed robot system, in which the success rate of the mushroom recognition success rate reaches 95%, the harvesting success rate reaches 86.8% (without considering mushroom damage), and the harvesting time for a single mushroom is 8.85 s. Full article

(This article belongs to the Special Issue Artificial Intelligence for Agricultural Robotics)

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20 pages, 2747 KiB

Open AccessEditor’s ChoiceArticle

Economic and Environmental Consequences of the ECJ Genome Editing Judgment in Agriculture

by Alexander Gocht, Nicola Consmüller, Ferike Thom and Harald Grethe

Agronomy 2021, 11(6), 1212; https://doi.org/10.3390/agronomy11061212 - 15 Jun 2021

Cited by 7 | Viewed by 4585

Abstract

Genome-edited crops are on the verge of being placed on the market and their agricultural and food products will thus be internationally traded soon. National regulations, however, diverge regarding the classification of genome-edited crops. Major countries such as the US and Brazil do [...] Read more.

Genome-edited crops are on the verge of being placed on the market and their agricultural and food products will thus be internationally traded soon. National regulations, however, diverge regarding the classification of genome-edited crops. Major countries such as the US and Brazil do not specifically regulate genome-edited crops, while in the European Union, they fall under GMO legislation, according to the European Court of Justice (ECJ). As it is in some cases impossible to analytically distinguish between products from genome-edited plants and those from non-genome-edited plants, EU importers may fear the risk of violating EU legislation. They may choose not to import any agricultural and food products based on crops for which genome-edited varieties are available. Therefore, crop products of which the EU is currently a net importer would become more expensive in the EU, and production would intensify. Furthermore, an intense substitution of products covered and not covered by genome editing would occur in consumption, production, and trade. We analyzed the effects of such a cease of EU imports for cereals and soy in the EU agricultural sector with the comparative static agricultural sector equilibrium model CAPRI. Our results indicate dramatic effects on agricultural and food prices as well as on farm income. The intensification of EU agriculture may result in negative net environmental effects in the EU as well as in an increase in global greenhouse gas (GHG) emissions. This suggests that trade effects should be considered when developing domestic regulation for genome-edited crops. Full article

(This article belongs to the Special Issue Precision Genome Editing for Plant Breeding)

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24 pages, 2502 KiB

Open AccessEditor’s ChoiceArticle

Disaggregating the Value of Conservation Agriculture to Inform Smallholder Transition to Sustainable Farming: A Mexican Case Study

by Marta Monjardino, Santiago López-Ridaura, Jelle Van Loon, Khondoker Abdul Mottaleb, Gideon Kruseman, Adaír Zepeda, Erick Ortiz Hernández, Juan Burgueño, Ravi Gopal Singh, Bram Govaerts and Olaf Erenstein

Agronomy 2021, 11(6), 1214; https://doi.org/10.3390/agronomy11061214 - 15 Jun 2021

Cited by 19 | Viewed by 5226

Abstract

Conservation Agriculture (CA) is promoted by research and development (R&D) agencies to sustainably intensify agricultural systems with the goals of improving food security and livelihoods and adapting food systems to global climate change. Despite the many benefits of CA, there are few farmers [...] Read more.

Conservation Agriculture (CA) is promoted by research and development (R&D) agencies to sustainably intensify agricultural systems with the goals of improving food security and livelihoods and adapting food systems to global climate change. Despite the many benefits of CA, there are few farmers around the world that have simultaneously implemented all facets of the strategy. In part, this reflects the challenges in applying, adapting, and understanding this complex and multi-dimensional agricultural innovation in the context of diverse farming systems. In this paper, we applied an integrated framework that combines bioeconomic simulation, risk analysis, adoption theory, and impact assessment to investigate how various combinations of CA components (no-tillage, soil cover, crop diversification, plus growing a new crop or variety) performed over a 10-year period in representative farms in a central Mexican case study. We found significant differences in profit, net value, downside risk, and risk-aversion cost between double-component scenarios (and improved CA to a lesser extent) and all other scenarios, which suggested that disaggregating CA into smaller component packages could increase farmer adoption in risky contexts. Our findings provided valuable insights on CA feasibility and could help establish policy and reporting metrics. The study highlighted the need for employing a range of research tools to understand the relative value of agricultural innovations and to identify and reduce trade-offs and uncertainty in farming systems. Full article

(This article belongs to the Special Issue Farmers’ Adoption of Agricultural Innovations and Their Impact)

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20 pages, 3933 KiB

Open AccessEditor’s ChoiceArticle

A Framework for Identification of Stable Genotypes Basedon MTSI and MGDII Indexes: An Example in Guar (Cymopsis tetragonoloba L.)

by Niranjana Kumara Benakanahalli, Shankarappa Sridhara, Nandini Ramesh, Tiago Olivoto, Gangaprasad Sreekantappa, Nissren Tamam, Ashraf M. M. Abdelbacki, Hosam O. Elansary and Shaimaa A. M. Abdelmohsen

Agronomy 2021, 11(6), 1221; https://doi.org/10.3390/agronomy11061221 - 15 Jun 2021

Cited by 69 | Viewed by 4061

Abstract

Guar, the most popular vegetable, is tolerant of drought and is a valuable industrial crop enormously grown across India, Pakistan, USA, and South Africa for pharmaceutically and cosmetically usable galactomannan (gum) content present in seed endosperm. Guar genotypes with productive traits which could [...] Read more.

Guar, the most popular vegetable, is tolerant of drought and is a valuable industrial crop enormously grown across India, Pakistan, USA, and South Africa for pharmaceutically and cosmetically usable galactomannan (gum) content present in seed endosperm. Guar genotypes with productive traits which could perform better in differential environmental conditions are of utmost priority for genotype selection. This could be achieved by employing multivariate trait analysis. In this context, Multi-Trait Stability Index (MTSI) and Multi-Trait Genotype-Ideotype Distance Index (MGIDI) were employed for identifying high-performing genotypes exhibiting multiple traits. In the current investigation, 85 guar accessions growing in different seasons were assessed for 15 morphological traits. The results obtained by MTSI and MGIDI indexes revealed that, out of 85, only 13 genotypes performed better across and within the seasons, and, based on the coincidence index, only three genotypes (IC-415106, IC-420320, and IC-402301) were found stable with high seed production in multi-environmental conditions. View on strengths and weakness as described by the MGIDI reveals that breeders concentrated on developing genotype with desired traits, such as quality of the gum and seed yield. The strength of the ideal genotypes in the present work is mainly focused on high gum content, short crop cycle, and high seed yield possessing good biochemical traits. Thus, MTSI and MGIDI serve as a novel tool for desired genotype selection process simultaneously in plant breeding programs across multi-environments due to uniqueness and ease in interpreting data with minimal multicollinearity issues. Full article

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17 pages, 9063 KiB

Open AccessEditor’s ChoiceArticle

Trichoderma and Phosphite Elicited Distinctive Secondary Metabolite Signatures in Zucchini Squash Plants

by Luigi Formisano, Begoña Miras-Moreno, Michele Ciriello, Christophe El-Nakhel, Giandomenico Corrado, Luigi Lucini, Giuseppe Colla and Youssef Rouphael

Agronomy 2021, 11(6), 1205; https://doi.org/10.3390/agronomy11061205 - 14 Jun 2021

Cited by 23 | Viewed by 3614

Abstract

Plant biostimulants are “green” solutions to improve crop production. Trichoderma spp. and phosphites, ordinarily used as biocontrol agents, can trigger phytostimulation, also promoting endogenous mechanisms involved in plant growth and development. The present study aimed at assessing the efficacy of a phosphite-based formulation [...] Read more.

Plant biostimulants are “green” solutions to improve crop production. Trichoderma spp. and phosphites, ordinarily used as biocontrol agents, can trigger phytostimulation, also promoting endogenous mechanisms involved in plant growth and development. The present study aimed at assessing the efficacy of a phosphite-based formulation (Phosphit-One) and Trichoderma harzianum-T22 on the morpho-physiological response and modulation of the metabolomics profile in zucchini squash plants (Cucurbita pepo L.) cultivated in controlled growth conditions (Fitotron^®). The highest values of fresh biomass production (390.9 g plant⁻¹) and root dry weight (5.6 g plant⁻¹) were obtained for Trichoderma-treated plants. This last treatment resulted in an improved physiological performance (SPAD index, CO₂ assimilation rate, and F_v/F_m ratio) measured 30 days after transplanting. Both Trichoderma and phosphite treatments induced a broad metabolic reprogramming in leaves, evident also for the phosphite treatment that did not result in a growth promotion. The microbial and the non-microbial treatments showed distinctive signatures in secondary metabolism yet, common responses could be also highlighted. For instance, both Trichoderma and phosphite triggered ROS-mediated signaling processes, together with the accumulation of phenylpropanoids, glucosinolates, and phytoalexins. Furthermore, a significant alteration of phytohormones was observed, with terpenoid gibberellins and brassinosteroids showing the largest differences. The metabolomic signatures induced by Trichoderma and phosphite in zucchini squash provided molecular insights into the processes underlying elicitation of plant defense due to biostimulation. Interestingly, the modulation of plant secondary metabolism by both treatments did not impair plant growth. Full article

(This article belongs to the Special Issue Toward Sustainability in Horticultural Crop Production Systems)

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13 pages, 1708 KiB

Open AccessEditor’s ChoiceArticle

Antioxidant Properties, γ-Aminobutyric Acid (GABA) Content, and Physicochemical Characteristics of Tomato Cultivars

by Shimeles Tilahun, Han-Ryul Choi, Min-Woo Baek, Lee-Hee Cheol, Ki-Wung Kwak, Do-Su Park, Tifsehit Solomon and Cheon-Soon Jeong

Agronomy 2021, 11(6), 1204; https://doi.org/10.3390/agronomy11061204 - 13 Jun 2021

Cited by 29 | Viewed by 5163

Abstract

Tomatoes are rich in secondary metabolites such as lycopene, β-carotene, phenolics, flavonoids, and vitamin C, which are responsible for their antioxidant activates. A high level of γ-Aminobutyric acid (GABA), a health-promoting functional compound, was also found to accumulate in tomato fruit. In addition [...] Read more.

Tomatoes are rich in secondary metabolites such as lycopene, β-carotene, phenolics, flavonoids, and vitamin C, which are responsible for their antioxidant activates. A high level of γ-Aminobutyric acid (GABA), a health-promoting functional compound, was also found to accumulate in tomato fruit. In addition to the internal quality attributes, the acceptance of the tomato fruit by consumers is highly dependent on appearance and taste. Hence, we conducted this study to evaluate ‘Tori’, ‘TY VIP’, ‘Mamirio’, and ‘Arya’ tomato cultivars based on their physicochemical characteristics, contents of secondary metabolites, and GABA content. The results have revealed that the tested cultivars were very firm, which renders them the best choice for postharvest distribution of fresh market tomatoes as they resist impacts during harvesting and postharvest operations. Based on total soluble solids (TSS), titratable acidity (TA), and Brix acid ratio (BAR) the choice of cultivar could be ‘Mamirio’ > ’Tori’ > ‘TY VIP’ > ‘Arya’. Apart from flavor intensity, ‘Mamirio’ and ’Tori’ also revealed the highest content of ascorbic acid while ‘Mamirio’ and ‘Arya’ had the highest carotenoids (lycopene and β-carotene) accumulation. On the other hand, the highest total phenolics content was recorded from ‘TY VIP’ and ‘Arya’. Moreover, the highest total flavonoids and GABA contents were recorded from ‘TY VIP’. Nevertheless, the antioxidant activity of ‘TY VIP’ was the lowest of all tested cultivars while the highest was recorded from ‘Mamirio’. Taken together, the findings of the present study could suggest that the consumers’ requirements could be better fulfilled by choosing cultivars for the specific target functional compounds. From the tested cultivars, if the target is ascorbic acid, carotenoids, and antioxidant activity then ‘Mamirio’ is the best choice. On the other hand, if the target is total phenolics, flavonoids, and GABA then ‘TY VIP’ is the best choice. One could also label ‘Mamirio’ as an ‘antioxidant tomato’ and ‘TY VIP’ as the ‘GABA tomato’. Full article

(This article belongs to the Special Issue Fruit and Vegetable Quality and Bioactive Compounds at Harvest and during Postharvest Storage)

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17 pages, 15044 KiB

Open AccessEditor’s ChoiceArticle

Rapid Detection and Counting of Wheat Ears in the Field Using YOLOv4 with Attention Module

by Baohua Yang, Zhiwei Gao, Yuan Gao and Yue Zhu

Agronomy 2021, 11(6), 1202; https://doi.org/10.3390/agronomy11061202 - 12 Jun 2021

Cited by 104 | Viewed by 7640

Abstract

The detection and counting of wheat ears are very important for crop field management, yield estimation, and phenotypic analysis. Previous studies have shown that most methods for detecting wheat ears were based on shallow features such as color and texture extracted by machine [...] Read more.

The detection and counting of wheat ears are very important for crop field management, yield estimation, and phenotypic analysis. Previous studies have shown that most methods for detecting wheat ears were based on shallow features such as color and texture extracted by machine learning methods, which have obtained good results. However, due to the lack of robustness of these features, it was difficult for the above-mentioned methods to meet the detection and counting of wheat ears in natural scenes. Other studies have shown that convolutional neural network (CNN) methods could be used to achieve wheat ear detection and counting. However, the adhesion and occlusion of wheat ears limit the accuracy of detection. Therefore, to improve the accuracy of wheat ear detection and counting in the field, an improved YOLOv4 (you only look once v4) with CBAM (convolutional block attention module) including spatial and channel attention model was proposed that could enhance the feature extraction capabilities of the network by adding receptive field modules. In addition, to improve the generalization ability of the model, not only local wheat data (WD), but also two public data sets (WEDD and GWHDD) were used to construct the training set, the validation set, and the test set. The results showed that the model could effectively overcome the noise in the field environment and realize accurate detection and counting of wheat ears with different density distributions. The average accuracy of wheat ear detection was 94%, 96.04%, and 93.11%. Moreover, the wheat ears were counted on 60 wheat images. The results showed that R² = 0.8968 for WD, 0.955 for WEDD, and 0.9884 for GWHDD. In short, the CBAM-YOLOv4 model could meet the actual requirements of wheat ear detection and counting, which provided technical support for other high-throughput parameters of the extraction of crops. Full article

(This article belongs to the Special Issue Applications of Deep Learning in Smart Agriculture)

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16 pages, 3870 KiB

Open AccessEditor’s ChoiceArticle

Foliar and Root Applications of Vegetal-Derived Protein Hydrolysates Differentially Enhance the Yield and Qualitative Attributes of Two Lettuce Cultivars Grown in Floating System

by Francesco Cristofano, Christophe El-Nakhel, Antonio Pannico, Maria Giordano, Giuseppe Colla and Youssef Rouphael

Agronomy 2021, 11(6), 1194; https://doi.org/10.3390/agronomy11061194 - 11 Jun 2021

Cited by 36 | Viewed by 4083

Abstract

Lettuce (Lactuca sativa L.) is a leafy vegetable cultivated widely for its fast and year-round production and its beneficial phytochemical content, which may be boosted further by plant biostimulants that are considered eco-sustainable means for enhancing horticultural crop production. A greenhouse experiment [...] Read more.

Lettuce (Lactuca sativa L.) is a leafy vegetable cultivated widely for its fast and year-round production and its beneficial phytochemical content, which may be boosted further by plant biostimulants that are considered eco-sustainable means for enhancing horticultural crop production. A greenhouse experiment was carried out to evaluate the yield and qualitative parameters of two differently pigmented lettuce cultivars grown in a floating raft system either untreated or treated (leaf, root or leaf/root application) with vegetal protein hydrolysates (PHs). For foliar application (F), lettuce plants were sprayed at a dose of 3 mL L⁻¹, whereas for root application, 0.15 (T1) or 0.3 (T2) mL L⁻¹ was applied to the nutrient solution alone or in combination with foliar spray (T1 + F and T2 + F) with the same foliar concentration. Bio-morphometric and production data were collected after harvest. Physiological and plant nutrition assays included leaf gas exchange, leaf fluorescence, SPAD index, mineral content, carotenoids, total phenols, total ascorbic acid content and antioxidant activities. Cultivar-specific reactions to biostimulant application were noted: whilst the green pigmented cultivar thrived under nutrient solution applications and recorded higher yield by 82.7% (T1) or (T1 + F) and 71.7% (T2), the red cultivar thrived under combined treatments, yielding 55.4% (T2 + F) higher than control and providing the most concentrated phytochemical content. These latter treatments also engendered the highest SPAD index, F_v/F_m ratio, CO₂ assimilation, stomatal conductance and transpiration. In addition, the T2 + F treatment boosted ‘Canasta’ hydrophilic antioxidant activity (21.9%) and total ascorbic acid (5.6-fold). Nutrient solution treatments alone proved advantageous when compared to foliar treatments, while mixed treatments proved genotype-specific. New research on genotype specificity of biostimulant effects is warranted for future use, in order to rationalize biostimulant application modes and dosages. Full article

(This article belongs to the Special Issue Biostimulants as Physiological Modulators of Crop Performance and Product Quality)

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15 pages, 648 KiB

Open AccessEditor’s ChoiceArticle

Intercropping Alfalfa into Silage Maize Can Be More Profitable Than Maize Silage Followed by Spring-Seeded Alfalfa

by Marisol T. Berti, Johanna Lukaschewsky and Dulan P. Samarappuli

Agronomy 2021, 11(6), 1196; https://doi.org/10.3390/agronomy11061196 - 11 Jun 2021

Cited by 22 | Viewed by 4156

Abstract

Intercropping of silage maize (Zea mays L.) and alfalfa (Medicago sativa L.) is not a common practice because alfalfa generally reduces maize grain and biomass yield. The objective of this research was to evaluate the productivity and profitability of silage maize–alfalfa [...] Read more.

Intercropping of silage maize (Zea mays L.) and alfalfa (Medicago sativa L.) is not a common practice because alfalfa generally reduces maize grain and biomass yield. The objective of this research was to evaluate the productivity and profitability of silage maize–alfalfa intercropping, with a goal to establish alfalfa and increase alfalfa productivity in the first year of production. The experiment was conducted in Fargo and Prosper, ND, USA, in 2014–2017. The design was a randomized complete block with four replicates and a split-plot arrangement. The main plot had two maize row-spacing treatments (RS), 61 and 76 cm, respectively. Treatments in the subplot were: (1) maize monoculture, (2) maize intercropped with alfalfa, (3) maize intercropped with alfalfa + prohexadione-calcium (PHX), and (4) spring-seeded alfalfa in the following year (simulating a maize–spring-seeded alfalfa crop sequence). Both alfalfa and maize were seeded the same day in May of 2014 at both locations. Prohexadione-calcium, a growth regulator to reduce internode length and avoid etiolation of alfalfa seedlings, did not improve alfalfa plant survival. Averaged across locations, RS did not have an effect on silage maize yield and alfalfa forage yield. Alfalfa established in intercropping with maize had almost double the forage yield in the following year compared with spring-seeded alfalfa following a crop of silage maize. Considering a two-year system, alfalfa intercropped with maize had higher net returns than a silage-maize followed by a spring-seeded alfalfa sequence. This system has the potential to get more growers to have alfalfa in the rotation skipping the typical low forage yield of alfalfa in the establishment year. Full article

(This article belongs to the Special Issue Multifunctional Forages)

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16 pages, 2917 KiB

Open AccessEditor’s ChoiceArticle

Effect of Salinity Stress on Physiological Changes in Winter and Spring Wheat

by Muhammad Sohail Saddiq, Shahid Iqbal, Muhammad Bilal Hafeez, Amir M. H. Ibrahim, Ali Raza, Esha Mehik Fatima, Heer Baloch, Jahanzaib, Pasqualina Woodrow and Loredana Filomena Ciarmiello

Agronomy 2021, 11(6), 1193; https://doi.org/10.3390/agronomy11061193 - 11 Jun 2021

Cited by 158 | Viewed by 13969

Abstract

Salinity is a leading threat to crop growth throughout the world. Salt stress induces altered physiological processes and several inhibitory effects on the growth of cereals, including wheat (Triticum aestivum L.). In this study, we determined the effects of salinity on five [...] Read more.

Salinity is a leading threat to crop growth throughout the world. Salt stress induces altered physiological processes and several inhibitory effects on the growth of cereals, including wheat (Triticum aestivum L.). In this study, we determined the effects of salinity on five spring and five winter wheat genotypes seedlings. We evaluated the salt stress on root and shoot growth attributes, i.e., root length (RL), shoot length (SL), the relative growth rate of root length (RGR-RL), and shoot length (RGR-SL). The ionic content of the leaves was also measured. Physiological traits were also assessed, including stomatal conductance (gs), chlorophyll content index (CCI), and light-adapted leaf chlorophyll fluorescence, i.e., the quantum yield of photosystem II (Fv′/Fm′) and instantaneous chlorophyll fluorescence (Ft). Physiological and growth performance under salt stress (0, 100, and 200 mol/L) were explored at the seedling stage. The analysis showed that spring wheat accumulated low Na+ and high K+ in leaf blades compared with winter wheat. Among the genotypes, Sakha 8, S-24, W4909, and W4910 performed better and had improved physiological attributes (gs, Fv′/Fm′, and Ft) and seedling growth traits (RL, SL, RGR-SL, and RGR-RL), which were strongly linked with proper Na⁺ and K⁺ discrimination in leaves and the CCI in leaves. The identified genotypes could represent valuable resources for genetic improvement programs to provide a greater understanding of plant tolerance to salt stress. Full article

(This article belongs to the Collection Crop Physiology and Stress)

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16 pages, 1472 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Compost and Fly Ash Treatment of Contaminated Soil on the Immobilisation and Bioavailability of Lead

by Monika Jakubus and Małgorzata Graczyk

Agronomy 2021, 11(6), 1188; https://doi.org/10.3390/agronomy11061188 - 10 Jun 2021

Cited by 9 | Viewed by 2771

Abstract

The study discusses changes in lead contents in soil and crops after application of compost and fly ash. A three-year experiment was conducted on narrow-leaved lupine (Lupinus angustifolius L.), camelina (Camelina sativa L.) and oat (Avena sativa L.), which were [...] Read more.

The study discusses changes in lead contents in soil and crops after application of compost and fly ash. A three-year experiment was conducted on narrow-leaved lupine (Lupinus angustifolius L.), camelina (Camelina sativa L.) and oat (Avena sativa L.), which were grown on medium soil fertilised with compost or fly ash (FA). The lead amounts in various combinations were evaluated using sequential (BCR analysis) and single (DTPA solution) methods. The total contents of lead and amounts of selected macronutrients were assessed in the biomass of plants. The Pb contents in the soil and plants were used to calculate the risk assessment code (RAC), individual contamination factor (ICF), bioconcentration factor (BCF) and contamination coefficient level (CCL). Lower amounts of bioavailable Pb in the soil were observed as a result of compost and FA application. Fly ash immobilised Pb more effectively, as evidenced by the BCF and CCL values. The increase in the Pb contents in the sequentially separated fractions and in plant biomass were caused by applied compost or FA. The Pb contents in exchangeable forms decreased, whereas its contents in residual forms increased. Full article

(This article belongs to the Special Issue Heavy Metal Pollution and Its Effects on Agriculture)

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18 pages, 2566 KiB

Open AccessEditor’s ChoiceArticle

Carbon Mineralization Dynamics of Organic Materials and Their Usage in the Restoration of Degraded Tropical Tea-Growing Soil

by Liyana Rallage Mahesh Chaminda Liyanage, Muhammad Firdaus Sulaiman, Roslan Ismail, Gamini Perera Gunaratne, Randombage Saman Dharmakeerthi, Minninga Geethika Neranjani Rupasinghe, Amoda Priyangi Mayakaduwa and Mohamed M. Hanafi

Agronomy 2021, 11(6), 1191; https://doi.org/10.3390/agronomy11061191 - 10 Jun 2021

Cited by 15 | Viewed by 3989

Abstract

Understanding carbon mineralization dynamics of organic amendments is essential to restore degraded lands. This study focused on the restoration potentials of tea-growing soils using organic materials available in tea ecosystems. The Selangor-Briah soil series association (Typic Endoaquepts) consisted of a high- (soil [...] Read more.

Understanding carbon mineralization dynamics of organic amendments is essential to restore degraded lands. This study focused on the restoration potentials of tea-growing soils using organic materials available in tea ecosystems. The Selangor-Briah soil series association (Typic Endoaquepts) consisted of a high- (soil A) and a low-carbon (soil B) soils were incubated with different organic materials and released carbon dioxide (CO₂) measured. Two kinetic models were applied to depict the mineralization process. Soil health parameters including microbial biomass carbon and nitrogen, dehydrogenase and catalase activities were determined to assess the restoration potentials. The parallel first-order kinetic model fitted well for all amendments. Gliricidia markedly enhanced the net cumulative CO₂ flux in both soils. Charged biochar, tea waste and Gliricidia improved the microbial biomass carbon by 79–84% in soil A and 82–93% in soil B, respectively. Microbial quotients and biomass nitrogen were increased over 50 and 70% in amended soils, respectively. Dehydrogenase activity was significantly accelerated over 80% by compost, charged biochar and tea waste. Charged biochar remarkably increased the soil catalase activity by 141%. Microbial biomass, dehydrogenase and catalase activities, and cumulative CO₂ flux were positively correlated (r > 0.452) with one another. The studied amendments showed greater potential in improving the soil quality, while charged biochar, raw biochar and compost enrich the soil recalcitrant C pool ensuring the soil health in long term. Even though biochar sequesters carbon, it has to be charged with nutrients to achieve the soil restoration goals. Full article

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

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17 pages, 2771 KiB

Open AccessEditor’s ChoiceArticle

Protective and Curative Effects of Trichoderma asperelloides Ta41 on Tomato Root Rot Caused by Rhizoctonia solani Rs33

by Ahmed A. Heflish, Ahmed Abdelkhalek, Abdulaziz A. Al-Askar and Said I. Behiry

Agronomy 2021, 11(6), 1162; https://doi.org/10.3390/agronomy11061162 - 6 Jun 2021

Cited by 53 | Viewed by 5501

Abstract

Two molecularly identified tomato isolates, Trichoderma asperelloides Ta41 and Rhizoctonia solani Rs33, were characterized and antagonistically evaluated. The dual culture technique showed that Ta41 had a high antagonistic activity of 83.33%, while a light microscope bioassay demonstrated that the Ta41 isolate over-parasitized the [...] Read more.

Two molecularly identified tomato isolates, Trichoderma asperelloides Ta41 and Rhizoctonia solani Rs33, were characterized and antagonistically evaluated. The dual culture technique showed that Ta41 had a high antagonistic activity of 83.33%, while a light microscope bioassay demonstrated that the Ta41 isolate over-parasitized the pathogen completely. Under greenhouse conditions, the application of Ta41 was able to promote tomato plant growth and had a significant increase in plant height, root length, and shoot fresh, shoot dry, root fresh, and root dry weight. It also improved chlorophyll content and total phenol content significantly, both in protective and in curative treatments. The protective treatment assay exhibited the lowest disease index (16.00%), while the curative treatment showed a disease index of 33.33%. At 20 days post-inoculation, significant increases in the relative expression levels of four defense-related genes (PR-1, PR-2, PR-3, and CHS) were observed in all Ta41-treated plants when compared with the non-treated plants. Interestingly, the plants treated with Ta41 alone showed the highest expression, with relative transcriptional levels of CHS, PR-3, PR-1, and PR-2 that were, compared with the control, 3.91-, 3.13-, 2.94-, and 2.69-fold higher, respectively, and the protective treatment showed relative transcriptional levels that were 3.50-, 3.63-, 2.39-, and 2.27-fold higher, respectively. Consequently, the ability of Ta41 to promote tomato growth, suppress Rs33 growth, and induce systemic resistance supports the incorporation of Ta41 as a potential bioagent for controlling root rot disease and increasing the productivity of crops, including tomatoes. Full article

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

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20 pages, 6732 KiB

Open AccessEditor’s ChoiceArticle

Semi-Transparent Organic Photovoltaics Applied as Greenhouse Shade for Spring and Summer Tomato Production in Arid Climate

by Rebekah Waller, Murat Kacira, Esther Magadley, Meir Teitel and Ibrahim Yehia

Agronomy 2021, 11(6), 1152; https://doi.org/10.3390/agronomy11061152 - 4 Jun 2021

Cited by 35 | Viewed by 5376

Abstract

Recognizing the growing interest in the application of organic photovoltaics (OPVs) with greenhouse crop production systems, in this study we used flexible, roll-to-roll printed, semi-transparent OPV arrays as a roof shade for a greenhouse hydroponic tomato production system during a spring and summer [...] Read more.

Recognizing the growing interest in the application of organic photovoltaics (OPVs) with greenhouse crop production systems, in this study we used flexible, roll-to-roll printed, semi-transparent OPV arrays as a roof shade for a greenhouse hydroponic tomato production system during a spring and summer production season in the arid southwestern U.S. The wavelength-selective OPV arrays were installed in a contiguous area on a section of the greenhouse roof, decreasing the transmittance of all solar radiation wavelengths and photosynthetically active radiation (PAR) wavelengths (400–700 nm) to the OPV-shaded area by approximately 40% and 37%, respectively. Microclimate conditions and tomato crop growth and yield parameters were measured in both the OPV-shaded (‘OPV’) and non-OPV-shaded (‘Control’) sections of the greenhouse. The OPV shade stabilized the canopy temperature during midday periods with the highest solar radiation intensities, performing the function of a conventional shading method. Although delayed fruit development and ripening in the OPV section resulted in lower total yields compared to the Control section (24.6 kg m⁻² and 27.7 kg m⁻², respectively), after the fourth (of 10 total) harvests, the average weekly yield, fruit number, and fruit mass were not significantly different between the treatment (OPV-shaded) and control group. Light use efficiency (LUE), defined as the ratio of total fruit yield to accumulated PAR received by the plant canopy, was nearly twice as high as the Control section, with 21.4 g of fruit per mole of PAR for plants in the OPV-covered section compared to 10.1 g in the Control section. Overall, this study demonstrated that the use of semi-transparent OPVs as a seasonal shade element for greenhouse production in a high-light region is feasible. However, a higher transmission of PAR and greater OPV device efficiency and durability could make OPV shades more economically viable, providing a desirable solution for co-located greenhouse crop production and renewable energy generation in hot and high-light intensity regions. Full article

(This article belongs to the Special Issue Photovoltaics and Electrification in Agriculture)

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12 pages, 1097 KiB

Open AccessEditor’s ChoiceArticle

Selenium Biofortification of Three Wild Species, Rumex acetosa L., Plantago coronopus L., and Portulaca oleracea L., Grown as Microgreens

by Martina Puccinelli, Beatrice Pezzarossa, Lucia Pintimalli and Fernando Malorgio

Agronomy 2021, 11(6), 1155; https://doi.org/10.3390/agronomy11061155 - 4 Jun 2021

Cited by 36 | Viewed by 4183

Abstract

Microgreens of wild herbs are a source of healthy compounds. Selenium (Se) biofortification of microgreens could help increase the Se content and thus contribute to Se requirements in humans. We evaluated whether three wild herbs, Rumex acetosa L., Plantago coronopus L., and Portulaca [...] Read more.

Microgreens of wild herbs are a source of healthy compounds. Selenium (Se) biofortification of microgreens could help increase the Se content and thus contribute to Se requirements in humans. We evaluated whether three wild herbs, Rumex acetosa L., Plantago coronopus L., and Portulaca oleracea L., were suitable for biofortification in order to obtain products with high nutraceutical value. In the first experiment, the three species were enriched with Na₂SeO₄ at 0 and 1.5 mg Se L⁻¹, and the effects of Se on the nutraceutical characteristics of microgreens were evaluated. In the second experiment, using P. oleracea enriched with 0, 1.5, 5, and 10 mg Se L⁻¹, we investigated whether there was a relation between the increasing Se concentrations in the nutrient solution and the Se content in microgreens. The Se added was taken up by roots and accumulated in the aerial part. P. coronopus exhibited the highest ability to accumulate selenium, and the Se-enriched microgreens showed the highest chlorophyll and flavonoid content. The strong correlation between the Se concentration in the growth solution and the Se accumulated in P. oleracea may enable the cultivation of microgreens with the targeted Se content. The resulting Se-biofortified microgreens of wild species could represent a new vegetable product with high nutraceutical value also ensuring a sufficient dietary intake of Se. Full article

(This article belongs to the Special Issue Sprouts, Microgreens and Edible Flowers as Novel Functional Foods)

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25 pages, 2196 KiB

Open AccessEditor’s ChoiceArticle

Use of Microbial Biostimulants to Increase the Salinity Tolerance of Vegetable Transplants

by Alessandro Miceli, Alessandra Moncada and Filippo Vetrano

Agronomy 2021, 11(6), 1143; https://doi.org/10.3390/agronomy11061143 - 3 Jun 2021

Cited by 50 | Viewed by 4977

Abstract

Vegetable plants are more sensitive to salt stress during the early growth stages; hence, the availability of poor-quality brackish water can be a big issue for the nursery vegetable industry. Microbial biostimulants promote growth and vigor and counterbalance salt stress in mature plants. [...] Read more.

Vegetable plants are more sensitive to salt stress during the early growth stages; hence, the availability of poor-quality brackish water can be a big issue for the nursery vegetable industry. Microbial biostimulants promote growth and vigor and counterbalance salt stress in mature plants. This study aimed to evaluate the application of plant growth-promoting microorganisms for improving salt tolerance of lettuce and tomato seedlings irrigated with different water salinity levels (0, 25, and 50 mM NaCl) during nursery growth. Two commercial microbial biostimulants were applied to the substrate before seeding: 1.5 g L⁻¹ of TNC Bactorr^S13 containing 1.3 × 10⁸ CFU g⁻¹ of Bacillus spp.; 0.75 g L⁻¹ of Flortis Micorrize containing 30% of Glomus spp., 1.24 × 10⁸ CFU g⁻¹ of Agrobacterium radiobacter, Bacillus subtilis, Streptomyces spp. and 3 × 10⁵ CFU g⁻¹ of Thricoderma spp. Many morpho-physiological parameters of lettuce and tomato seedlings suffered the negative effect of salinity. The use of the microbial biostimulants modified seedling growth and its response to salt stress. They had a growth-promoting effect on the unstressed seedlings increasing fresh and dry biomass accumulation, leaf number, and leaf area and were successful in increasing salinity tolerance of seedlings especially when using Flortis Micorizze that enhanced salinity tolerance up to 50 mM NaCl. The inoculation of the substrate with microbial biostimulants could represent a sustainable way to improve lettuce and tomato transplant quality and to use brackish water in vegetable nurseries limiting its negative effect on seedling growth. Full article

(This article belongs to the Special Issue Water and Nitrogen Use Efficiency of Horticultural Crops under Abiotic Stress)

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16 pages, 2136 KiB

Open AccessEditor’s ChoiceArticle

Hormone Profiles and Antioxidant Activity of Cultivated and Wild Tomato Seedlings under Low-Temperature Stress

by Parviz Heidari, Mohammad Reza Amerian and Gianni Barcaccia

Agronomy 2021, 11(6), 1146; https://doi.org/10.3390/agronomy11061146 - 3 Jun 2021

Cited by 33 | Viewed by 3795

Abstract

Low temperature is a major limiting factor for the growth and reproduction of some plant species, such as tomato. So far, few studies have been conducted on the effects of low temperature, and the mechanisms of plants’ response to this type of stress [...] Read more.

Low temperature is a major limiting factor for the growth and reproduction of some plant species, such as tomato. So far, few studies have been conducted on the effects of low temperature, and the mechanisms of plants’ response to this type of stress is not fully clear. In the current study, the effects of low, nonfreezing temperature (10 °C for three days) on the hormone content, antioxidant activity, and expression patterns of cold-related genes in the leaves of cold-tolerant species (Solanum habrochaites Accession ‘LA1777′) and cold-susceptible species (Solanum lycopersicum cultivar ‘Moneymaker’) were investigated. Low temperature increased the abscisic acid (ABA) content in both tomato species, while the content of zeatin-type cytokinins (ZT) increased in the cold-tolerant species. However, the content of indole-3-acetic acid (IAA) and gibberellic acid (GA) reduced in response to low temperature in susceptible species. Accordingly, cytokinin (CK) is identified as an important hormone associated with low-temperature stress in tomato. In addition, our results indicate that the C-repeat/DRE binding factor 1 (CBF1) gene is less induced in response to low temperature in tomato, although transcription of the inducer of CBF expression 1 (ICE1) gene was upregulated under low temperature in both tomato species. It seems that ICE1 may modulate cold-regulated (COR) genes in a CBF-independent way. In addition, in response to low temperature, the malondialdehyde (MDA) level and membrane stability index (MSI) increased in the susceptible species, indicating that low temperature induces oxidative stress. Additionally, we found that glutathione peroxidase is highly involved in reactive oxygen species (ROS) scavenging induced by low temperature, and antioxidants are more induced in tolerant species. Overall, our results suggest that sub-optimal temperatures promote oxidative stress in tomato and CK is introduced as a factor related to the response to low temperature that requires deeper attention in future breeding programs of tomato. Full article

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14 pages, 708 KiB

Open AccessEditor’s ChoiceArticle

Agronomic and In Vitro Quality Evaluation of Dual-Purpose Cereals Clipped at Variable Ages and Their Utilization in Rabbit Feeding

by Heba S. A. Salama, Assem M. Safwat, Osama H. Elghalid and Ahmed M. Abd El-Hady

Agronomy 2021, 11(6), 1147; https://doi.org/10.3390/agronomy11061147 - 3 Jun 2021

Cited by 5 | Viewed by 2490

Abstract

The present study included two experiments; the first one investigated the forage productivity and in vitro quality of a single cut taken at different plant ages (45, 60, and 75 days after sowing—DAS) from four prominent cereal crops, namely, barley, oat, triticale, and [...] Read more.

The present study included two experiments; the first one investigated the forage productivity and in vitro quality of a single cut taken at different plant ages (45, 60, and 75 days after sowing—DAS) from four prominent cereal crops, namely, barley, oat, triticale, and ryegrass, grown during two successive winter seasons in Northern Egypt. In addition, the effect of plant age at forage removal on the crop’s regrowth ability and final grain yield was quantified. The second experiment studied the biological in vivo effects of the four crops’ hay cut at the optimum plant age on growth performance, feed utilization, and apparent nutrients’ digestibility of growing rabbits. Despite the progressive increase in the fresh and dry matter yields produced from the four crops with later forage removal and the relatively high quality of the forage removed at 45 DAS, 1st experiment concluded that forage removal at 60 DAS produced a reasonable amount of fresh and dry matter yields with appropriate in vitro quality. Meanwhile, the gain in forage yield, when forage was removed at 60 DAS, was enough to compensate for the consequent reduction in grain yield of the four evaluated crops. The inclusion of variable percentages (0, 10, and 20%) of the four tested crops’ hay, when cut at 60 DAS, in the rabbit’s diet (2nd experiment), resulted in non-significant variations in the rabbit’s final body weight. Meanwhile, regardless of the percentage, the rabbits that were fed on diets including ryegrass hay and barley hay had the highest significant daily weight gain. The best feed conversion ratios were obtained by the rabbits that were fed on diets containing 10 and 20% ryegrass hay as well as 20% triticale hay. The highest dry matter, organic matter, and crude protein digestibility coefficients were obtained by both groups of rabbits that were fed on diets containing 20% ryegrass hay and barley hay. The inclusion of any of the four crops’ hay in the rabbits’ diet resulted in significantly higher digestibility coefficients for all nutrients compared to the control rabbits except for ether extract digestibility. Among the four evaluated crops’ hay, ryegrass hay was found to have an outstanding impact on the productive performance and digestibility of growing rabbits. In growing dual-purpose cereals, it is recommended to cut the crops at 60 DAS to achieve the optimum balance between forage yield and quality on the one hand and final grain yield on the other hand. Moreover, when cut at 60 DAS, the evaluated hay of the four crops was adequate to be included in the rabbits’ diet up to 20% substitution of the commercial fiber sources. Full article

(This article belongs to the Special Issue Multifunctional Forages)

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12 pages, 3378 KiB

Open AccessEditor’s ChoiceArticle

Chemical Composition and Allelopathic Effect of Essential Oil of Litsea pungens

by Qingbo Kong, Lijun Zhou, Xiaoju Wang, Siyuan Luo, Jiajia Li, Hanyong Xiao, Xinyao Zhang, Tingting Xiang, Shiling Feng, Tao Chen, Ming Yuan and Chunbang Ding

Agronomy 2021, 11(6), 1115; https://doi.org/10.3390/agronomy11061115 - 30 May 2021

Cited by 21 | Viewed by 4638

Abstract

Natural plant resources with herbicidal activity may be substitutes for synthetic chemical pesticides, likewise aromatic plant extracts, especially essential oils. Essential oil from Litsea pungens has been proved to possess a strong antibacterial property. Interestingly, we found the essential oil also showed a [...] Read more.

Natural plant resources with herbicidal activity may be substitutes for synthetic chemical pesticides, likewise aromatic plant extracts, especially essential oils. Essential oil from Litsea pungens has been proved to possess a strong antibacterial property. Interestingly, we found the essential oil also showed a strong allelopathic capacity. Therefore, in the present work, the chemical composition of the essential oil from the fruit of L. pungens was analyzed by gas chromatography–mass spectrometry (GC–MS). The weed control abilities of the essential oil were also further evaluated. The results show that the yield of essential oil extracted by steam distillation was 1.4%, and 17 compounds, mainly terpenoids, were identified by GC–MS. In allelopathic tests, the essential oil exhibited a negative effect on seed germination rate and seedling growth of Lolium perenne and Bidenspilosa. Moreover, chlorophyll content, malondialdehyde content, electrolyte leakage, catalase, superoxide dismutase and peroxidase of seedlings treated with essential oil were also negatively affected. This work could provide a better understanding of the rational utilization of L. pungens essential oil for crop cultivation and further development of environment-friendly herbicides. Full article

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18 pages, 3587 KiB

Open AccessEditor’s ChoiceArticle

Effect of Biofertilizers Application on Soil Biodiversity and Litter Degradation in a Commercial Apricot Orchard

by Elena Baldi, Paola Gioacchini, Daniela Montecchio, Stefano Mocali, Livio Antonielli, Giorgio Masoero and Moreno Toselli

Agronomy 2021, 11(6), 1116; https://doi.org/10.3390/agronomy11061116 - 30 May 2021

Cited by 20 | Viewed by 5485

Abstract

The aim of the present experiment was to determine if the supply of biofertilizers could differently stimulate the native microbiota, thus determining different patterns of organic material decomposition processes. The microbial composition of soil and litter was investigated by next generation sequencing using [...] Read more.

The aim of the present experiment was to determine if the supply of biofertilizers could differently stimulate the native microbiota, thus determining different patterns of organic material decomposition processes. The microbial composition of soil and litter was investigated by next generation sequencing using a metabarcoding approach. The chemical structure of the decomposing litterbags was investigated through the TG-DTA analysis and NIR spectroscopy. The study was conducted in an apricot orchard in Italy, and two different type of biofertilizers (AMF and Trichoderma spp.) were compared to unfertilized control over one year. Bacteria and fungi in soil, 162 days from litter deposition, evidenced differentiated clusters for control and both biofertilizers; on the other hand, only fungal composition of litterbags was modified as a consequence of Trichoderma spp. supply; no effect was observed in the bacterial community of litterbags. NIR and TG-DTA analysis evidenced a significant change over time of the chemical composition of litterbags with a faster degradation as a consequence of Trichoderma spp. supply testified by a higher degradation coefficient (1.9) than control (1.6) and AMF (1.7). The supply of biofertilizers partially modified the bacteria community of soil, while Trichoderma spp. Influenced the fungal community of the litter. Moreover, Trichoderma spp. Evidenced a faster and higher degradation of litter than AMF-biofertilizers, laying the foundation for an efficient use in orchard. Full article

(This article belongs to the Special Issue Soil-Plant Interaction: Focus on Plant Growth and Soil Biodiversity)

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15 pages, 1118 KiB

Open AccessEditor’s ChoiceArticle

Effect of Nutrient Solution pH on the Growth, Yield and Quality of Taraxacum officinale and Reichardia picroides in a Floating Hydroponic System

by Alexios A. Alexopoulos, Efstathios Marandos, Anna Assimakopoulou, Nikolina Vidalis, Spyridon A. Petropoulos and Ioannis C. Karapanos

Agronomy 2021, 11(6), 1118; https://doi.org/10.3390/agronomy11061118 - 30 May 2021

Cited by 35 | Viewed by 7982

Abstract

Given the important medicinal and nutritional value of wild edible greens, the last few years there is an increasing interest for their domestication and commercial exploitation. However, information concerning their adaptation to environmental conditions and their response to modern agricultural systems are scarce. [...] Read more.

Given the important medicinal and nutritional value of wild edible greens, the last few years there is an increasing interest for their domestication and commercial exploitation. However, information concerning their adaptation to environmental conditions and their response to modern agricultural systems are scarce. In the present study, the effect of nutrient solution pH (4.0, 5.5 and 7.0) on the growth, chemical composition and inorganic nutrition of Taraxacum officinale and Reichardia picroides plants grown indoors in a floating hydroponic system was evaluated. Both species performed better at pH 5.5 and were slightly affected by pH 7.0, whereas pH 4.0 was not prohibitive for growth for both species, although R. picroides was less tolerant than T. officinale at low pH. Moreover, pH 4.0 did not severely affect nutrients uptake and transport within the plant tissues, suggesting that R. picroides susceptibility to low pH should not be attributed to nutrients imbalance. Nevertheless, low pH positively enhanced the content in total soluble solids, total phenolics, chlorophylls (a, b and total) and carotenoids, and decreased nitrates in both species. In conclusion, the studied species could be successfully grown in soilless systems with nutrient solutions of varied pH. Moreover, low pH levels (pH = 4.0) seemed to be beneficial to nutritional and dietary value in both species highlighting the potential of commercial cultivation under adverse conditions, especially in sustainable farming systems. Full article

(This article belongs to the Special Issue Cultivation Practices, Pharmaceutical and Nutritional Value of Weeds)

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15 pages, 1660 KiB

Open AccessEditor’s ChoiceArticle

Citrus Varieties with Different Tolerance Grades to Tristeza Virus Show Dissimilar Volatile Terpene Profiles

by Salvatore Guarino, Loredana Abbate, Francesco Mercati, Sergio Fatta Del Bosco, Antonio Motisi, Mokhtar Abdulsattar Arif, Gabriele Cencetti, Eleonora Palagano and Marco Michelozzi

Agronomy 2021, 11(6), 1120; https://doi.org/10.3390/agronomy11061120 - 30 May 2021

Cited by 19 | Viewed by 4973

Abstract

Plants produce considerable amounts of volatile organic compounds (VOCs) with several biological functions, including protection against biotic agents such as viruses and their vectors. In citrus species, these metabolites can be related with their different susceptibility/tolerance toward the Tristeza virus (CTV), one of [...] Read more.

Plants produce considerable amounts of volatile organic compounds (VOCs) with several biological functions, including protection against biotic agents such as viruses and their vectors. In citrus species, these metabolites can be related with their different susceptibility/tolerance toward the Tristeza virus (CTV), one of the main biotic constraints for the citrus industry. The objective of this study was to compare the VOCs pattern from the leaves of a CTV-susceptible citrus variety such as Citrus aurantium and from three CTV-tolerant varieties: Citrus volkameriana, Carrizo citrange, and Forner-Alcaide no. 5. The VOCs emitted were analyzed via the headspace SPME method, while plant metabolites sequestered in the leaves were analyzed by heptane extraction followed by GC-MS. The results indicated that the majority of the VOCs emitted and sequestered in the leaves of the varieties tolerant and susceptible to CTV are constituted mainly by volatile terpenes (VTs) that exhibit strong qualitative/quantitative differences among the profiles of the four citrus species. In detail, the VOC emission indicated different patterns between C. aurantium and C. volkameriana and from both of them in comparison with Forner-Alcaide no. 5 and Carrizo citrange that exhibited more similarities, with the last two characterized by a higher presence of sesquiterpenes. The data obtained from the analysis of the VOCs sequestered in leaf tissues of the CTV-tolerant varieties indicated a higher presence of monoterpenes such as limonene, α-pinene, and p-cymene, known to be the main components of several plant extracts showing deterrent properties toward viruses and insect vectors. As VOC evaluation is a fast and noninvasive measure of phenotypic dynamics, allowing the association of plant phenotypes in accordance to plant disease resistance and/or stress tolerance, the possible implications of such differences in terms of tolerance grade to CTV and/or its related vectors are discussed. Full article

(This article belongs to the Special Issue Citrus Production and Protection from Pests and Diseases)

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20 pages, 7707 KiB

Open AccessEditor’s ChoiceArticle

Ovaries of Chrysanthemum Irradiated with High-Energy Photons and High-Energy Electrons Can Regenerate Plants with Novel Traits

by Natalia Miler, Iwona Jedrzejczyk, Seweryn Jakubowski and Janusz Winiecki

Agronomy 2021, 11(6), 1111; https://doi.org/10.3390/agronomy11061111 - 29 May 2021

Cited by 17 | Viewed by 4916

Abstract

Classical mutation breeding using physical factors is a common breeding method for ornamental crops. The aim of our study was to examine the utility of ovaries excised from irradiated inflorescences of Chrysanthemum × morifolium (Ramat.) as explants for breeding purposes. We studied the [...] Read more.

Classical mutation breeding using physical factors is a common breeding method for ornamental crops. The aim of our study was to examine the utility of ovaries excised from irradiated inflorescences of Chrysanthemum × morifolium (Ramat.) as explants for breeding purposes. We studied the in vitro regeneration capacity of the ovaries of two chrysanthemum cultivars: ‘Profesor Jerzy’ and ‘Karolina’ preceded by irradiation with high-energy photons (total dose 5, 10 and 15 Gy) and high-energy electrons (total dose 10 Gy). Growth and inflorescence parameters of greenhouse acclimatized regenerants were recorded, and ploidy level was estimated with flow cytometry. The strong impact of genotype on regeneration efficiency was recorded—cultivar ‘Karolina’ produced only 7 viable shoots, while ‘Profesor Jerzy’ produced totally 428 shoots. With an increase of irradiation dose, the regeneration decreased, the least responsive were explants irradiated with 15 Gy high-energy photons and 10 Gy high-energy electrons. Regenerants of ‘Profesor Jerzy’ obtained from these explants possessed shorter stem and flowered later. The highest number of stable, color and shape inflorescence variations were obtained from explants treated with 10 Gy high-energy photons. Variations of inflorescences were predominantly changes of shape—from full to semi-full. New color phenotypes were dark yellow, light yellow and pinkish, among them only the dark yellow phenotype remained stable during second year cultivation. None of the regenerants were haploid. The application of ovaries irradiated within the whole inflorescence of chrysanthemum can be successfully applied in the breeding programs, provided the mother cultivar regenerate in vitro efficiently. Full article

(This article belongs to the Special Issue Biotechnological Applications in Horticulture and Vegetable Crops)

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14 pages, 2189 KiB

Open AccessEditor’s ChoiceArticle

Physical, Nutritional and Functional Properties of Walnuts Genotypes (Juglans regia L.) from Romania

by Olimpia A. Iordănescu, Isidora Radulov, Ioana P. Buhan, Ileana Cocan, Adina A. Berbecea, Iuliana Popescu, Daniela S. Poșta, Dorin Camen and Dacian Lalescu

Agronomy 2021, 11(6), 1092; https://doi.org/10.3390/agronomy11061092 - 28 May 2021

Cited by 23 | Viewed by 4577

Abstract

Walnut (Juglans regia L.) is the oldest fruit grown in the world and grows spontaneously almost throughout Romania. In this study, the physical properties and chemical composition of twenty types of walnuts from three different locations in Romania were studied. The physical [...] Read more.

Walnut (Juglans regia L.) is the oldest fruit grown in the world and grows spontaneously almost throughout Romania. In this study, the physical properties and chemical composition of twenty types of walnuts from three different locations in Romania were studied. The physical analyzes that were performed were: walnut dimensions and shape properties (nut diameter, nut length, nut shape and nut size), fruit properties (walnut weight, walnut kernel weight and percentage of kernel) and external properties of walnut (walnut kernel extraction, kernel color and shell roughness). The proximate chemical composition (content of water, ash, lipids, proteins and carbohydrates) was determined by standardized AOAC methods, while fatty compounds were determined by GSMS. Water content ranged from 1.23% to 5.00%, mineral content between 1.31% and 2.49%, lipids content between 56.09% and 66.56% and protein content ranged between 12.73% and 20.413%. Based on these, the carbohydrate content and nutritional value of the 20 walnut samples were calculated. In all samples, saturated palmitic acid (C16:0) and stearic acid (C18:0) as well as unsaturated oleic (C18:1), linoleic (C18:2) and linolenic (C18:3) fatty acids were determined. A statistical analysis was also performed correlating the results obtained from the chemical analyzes of the walnuts. Full article

(This article belongs to the Special Issue Agricultural Products: Nutritional Value and Functional Properties)

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13 pages, 3283 KiB

Open AccessEditor’s ChoiceArticle

Nitrogen Supply Affects Grain Yield by Regulating Antioxidant Enzyme Activity and Photosynthetic Capacity of Maize Plant in the Loess Plateau

by Kai Yue, Lingling Li, Junhong Xie, Setor Kwami Fudjoe, Renzhi Zhang, Zhuzhu Luo and Sumera Anwar

Agronomy 2021, 11(6), 1094; https://doi.org/10.3390/agronomy11061094 - 28 May 2021

Cited by 24 | Viewed by 3901

Abstract

Nitrogen (N) is the most limiting nutrient for maize, and appropriate N fertilization can promote maize growth and yield. The effect of N fertilizer rates and timings on morphology, antioxidant enzymes, and grain yield of maize (Zea mays L.) in the Loess [...] Read more.

Nitrogen (N) is the most limiting nutrient for maize, and appropriate N fertilization can promote maize growth and yield. The effect of N fertilizer rates and timings on morphology, antioxidant enzymes, and grain yield of maize (Zea mays L.) in the Loess Plateau of China was evaluated. The four N levels, i.e., 0 (N0), 100 (N1), 200 (N2), and 300 (N3) kg ha⁻¹, were applied at two timings (T1, one-third N at sowing and two-thirds at the six-leaf stage of maize; T2, one-third applied at sowing, six-leaf stage, and eleven-leaf stage of maize). The results show that N2 and N3 significantly increased the plant height, stem and leaf dry weight, and leaf area index of maize compared with a non-N-fertilized control (N0). The net photosynthetic rate, transpiration rate, stomatal conductance, and leaf chlorophyll contents were lower, while the intercellular carbon dioxide concentration was higher for non-fertilized plants compared to fertilized plants. The activities of peroxidase (POD) and superoxide dismutase (SOD) increased with N rate, but the difference between 200 and 300 kg ha⁻¹ was not significant; further, the isozyme bands of POD and SOD also changed with their activities. Compared with a non-N-fertilized control, N2 and N3 significantly increased grain yield by 2.76- and 3.11-fold in 2018, 2.74- and 2.80-fold in 2019, and 2.71- and 2.89-fold in 2020, and there was no significant difference between N2 and N3. N application timing only affected yield in 2018. In conclusion, 200 kg N ha⁻¹ application increased yield through optimizing the antioxidant enzyme system, increasing photosynthetic capacity, and promoting dry matter accumulation. Further research is necessary to evaluate the response of more cultivars under more seasons to validate the results obtained. Full article

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18 pages, 6095 KiB

Open AccessEditor’s ChoiceArticle

Analysis of the Viability of a Photovoltaic Greenhouse with Semi-Transparent Amorphous Silicon (a-Si) Glass

by José-Ramón Aira, Sara Gallardo-Saavedra, Marcia Eugenio-Gozalbo, Víctor Alonso-Gómez, Miguel-Ángel Muñoz-García and Luis Hernández-Callejo

Agronomy 2021, 11(6), 1097; https://doi.org/10.3390/agronomy11061097 - 28 May 2021

Cited by 18 | Viewed by 4688

Abstract

For decades, society has been changing towards an energy mix that enhances the use of renewable sources and a more distributed generation of energy. The agricultural sector is included in this trend, which is why several studies are currently being carried out focused [...] Read more.

For decades, society has been changing towards an energy mix that enhances the use of renewable sources and a more distributed generation of energy. The agricultural sector is included in this trend, which is why several studies are currently being carried out focused on the use of solar energy in greenhouses. This article aims to demonstrate the viability of a greenhouse that integrates, as a novelty, semi-transparent amorphous silicon photovoltaic (PV) glass (a-Si), covering the entire roof surface and the main sides of the greenhouse. The designed prototype is formed by a simple rectangular structure 12 m long and 2.5 m wide, with a monopitch roof, oriented to the southwest, and with a 35° inclination. The greenhouse is divided into two contiguous equal sections, each with an area of 15 m², and physically separated by an interior partition transparent wall. The surface enclosure of one of the sections is made of conventional glass, and the one of the other, of PV glass. How the presence of semitransparent PV glass influences the growth of horticultural crops has been studied, finding that it slightly reduces the production of vegetal mass and accelerates the apical growth mechanism of heliophilic plants. However, from a statistical point of view, this influence is negligible, so it is concluded that the studied technology is viable for horticultural production. The energy balance carried out indicates that the energy produced by the PV system is greater than the energy consumed by the greenhouse, which shows that the greenhouse is completely viable and self-sufficient for sites with the adequate solar resource. Full article

(This article belongs to the Special Issue Photovoltaics and Electrification in Agriculture)

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16 pages, 754 KiB

Open AccessEditor’s ChoiceArticle

Effect of Exogenously Applied Methyl Jasmonate on Yield and Quality of Salt-Stressed Hydroponically Grown Sea Fennel (Crithmum maritimum L.)

by M. Hatim Labiad, Almudena Giménez, Hafise Varol, Yüksel Tüzel, Catalina Egea-Gilabert, Juan A. Fernández and María del Carmen Martínez-Ballesta

Agronomy 2021, 11(6), 1083; https://doi.org/10.3390/agronomy11061083 - 27 May 2021

Cited by 24 | Viewed by 3339

Abstract

Salt stress is one of the main limiting factors for plant growth and crop yield. Halophytes have been postulated as a new food source since they are able to grow under saline environments and have suitable minerals and bioactive compounds. See fennel Crithmum [...] Read more.

Salt stress is one of the main limiting factors for plant growth and crop yield. Halophytes have been postulated as a new food source since they are able to grow under saline environments and have suitable minerals and bioactive compounds. See fennel Crithmum maritimum L. is a facultative halophyte moderately tolerant to salinity. This study was carried out in order to determine the effect spraying methyl jasmonate (MeJa) on the leaves had on the growth and nutritional quality of NaCl-treated sea fennel plants grown in a hydroponic system. For that, the seedlings were treated with (a) 0.5 mM MeJa, (b) 150 mM NaCl, and (c) 0.5 mM MeJa + 150 mM NaCl. The results showed that NaCl reduced the shoot biomass of baby leaf plants, but the addition of MeJa enabled partial recovery. At the same time, when compared with the plants treated only with NaCl, MeJa favoured the Ca and K uptake and translocation to the leaves of saline-treated plants. However, MeJa did not reduce Na levels. In all treatments, nitrate and nitrite ions were in the range of the acceptable daily intake (ADI) and essential fatty acid content was elevated, although the addition of MeJa to NaCl-treated plants reduced linolenic and linoleic acid contents as compared to the plants treated only with NaCl. Total phenolic compounds were not recovered by MeJa after their decrease by salinity and no differences in antioxidant activity was found between treatments. However, all the plants maintained their antioxidant nutritional properties and increased total flavonoids after MeJa spraying to NaCl-treated plants. These results showed that MeJa spraying alleviated the negative effects of salt stress in C. maritimum grown in floating systems, improving the growth of their edible parts and increasing the total flavonoid and mineral content without affecting the total antioxidant capacity of the plant. Full article

(This article belongs to the Special Issue Using Our Agrobiodiversity: Plant-Based Solutions to Feed the World)

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16 pages, 5386 KiB

Open AccessEditor’s ChoiceArticle

Effects of Phosphorus Ensembled Nanomaterials on Nutrient Uptake and Distribution in Glycine max L. under Simulated Precipitation

by Qingqing Li, Chuanxin Ma, Jason C. White and Baoshan Xing

Agronomy 2021, 11(6), 1086; https://doi.org/10.3390/agronomy11061086 - 27 May 2021

Cited by 17 | Viewed by 3891

Abstract

Nanoscale hydroxyapatite (nHA) was synthesized to investigate its potential as a phosphorus (P) ensembled nanofertilizer, using soybean (Glycine max L.) as a model plant. The conventional analogue phosphate (pi) was used for comparison with the synthesized nHA. Varied precipitation intensities (0%, 30%, [...] Read more.

Nanoscale hydroxyapatite (nHA) was synthesized to investigate its potential as a phosphorus (P) ensembled nanofertilizer, using soybean (Glycine max L.) as a model plant. The conventional analogue phosphate (pi) was used for comparison with the synthesized nHA. Varied precipitation intensities (0%, 30%, 60%, and 100%) were simulated by adding selected volumes of the P fertilizers (nHA or pi) via foliar spray and soil amendment. The total amounts of added P were the same across all the treatments. The importance of a wash-off effect was investigated on foliar-treated seedlings by evaluating different watering heights (20, 120, and 240 cm above the seedlings). Fresh weight, pigment content, macro-, and micronutrient contents were measured in soybean tissues across all the treatments after 4 weeks of greenhouse cultivation. The synthesized nHA showed superior effects on plant nutrient content upon high precipitation intensities. For example, at 100% precipitation intensity, there was 32.6% more P and 33.2% more Ca in shoots, 40.6% more P and 45.4% more Ca in roots, and 37.9% more P and 82.3% more Ca in pods, as compared to those with pi treatment, respectively. No impact on soybean biomass was evident upon the application of nHA or pi. Further investigation into customizing nHA to enhance its affinity with crop leaves and to extend retention time on the leaf surface is warranted given that the present study did not show significant positive impacts of nHA on soybean growth under the effects of precipitation. Taken together, our findings increase understanding of the potential application of nHA as a nano-enabled fertilizer in sustainable agriculture. Full article

(This article belongs to the Special Issue Application of Nanotechnology in Sustainable Agriculture)

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17 pages, 1450 KiB

Open AccessEditor’s ChoiceArticle

Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

by Aleksandra Ukalska-Jaruga, Romualda Bejger, Guillaume Debaene and Bożena Smreczak

Agronomy 2021, 11(6), 1067; https://doi.org/10.3390/agronomy11061067 - 26 May 2021

Cited by 46 | Viewed by 6111

Abstract

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as [...] Read more.

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties. Full article

(This article belongs to the Special Issue Humic Substances: A Novel Eco-Friendly Fertilizer)

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14 pages, 2225 KiB

Open AccessEditor’s ChoiceArticle

Impact of an Exotic Invasive Pest, Spodoptera frugiperda (Lepidoptera: Noctuidae), on Resident Communities of Pest and Natural Enemies in Maize Fields in Kenya

by Bonoukpoè Mawuko Sokame, Boaz Musyoka, Julius Obonyo, François Rebaudo, Elfatih M. Abdel-Rahman, Sevgan Subramanian, Dora Chao Kilalo, Gérald Juma and Paul-André Calatayud

Agronomy 2021, 11(6), 1074; https://doi.org/10.3390/agronomy11061074 - 26 May 2021

Cited by 17 | Viewed by 3558

Abstract

The interactions among insect communities influence the composition of pest complexes that attack crops and, in parallel, their natural enemies, which regulate their abundance. The lepidopteran stemborers have been the major maize pests in Kenya. Their population has been regulated by natural enemies, [...] Read more.

The interactions among insect communities influence the composition of pest complexes that attack crops and, in parallel, their natural enemies, which regulate their abundance. The lepidopteran stemborers have been the major maize pests in Kenya. Their population has been regulated by natural enemies, mostly parasitoids, some of which have been used for biological control. It is not known how a new exotic invasive species, such as the fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera, Noctuidae), may affect the abundance and parasitism of the resident stemborers. For this reason, pest and parasitism surveys have been conducted, before and after the FAW invaded Kenya, in maize fields in 40 localities across 6 agroecological zones (AEZs) during the maize-growing season, as well as at 3 different plant growth stages (pre-tasseling, reproductive, and senescence stages) in 2 elevations at mid-altitude, where all maize stemborer species used to occur together. Results indicated that the introduction of the FAW significantly correlated with the reduction of the abundance of the resident communities of maize stemborers and parasitoids in maize fields; moreover, the decrease of stemborer density after the arrival of FAW occurred mostly at both reproductive and senescent maize stages. It also suggests a possible displacement of stemborers by FAW elsewhere; for example, to other cereals. However, since this study was conducted only three years after the introduction of the FAW, further studies will need to be conducted to confirm such displacements. Full article

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

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14 pages, 2243 KiB

Open AccessEditor’s ChoiceArticle

Use Bottom Sediment to Agriculture—Effect on Plant and Heavy Metal Content in Soil

by Witold Kazberuk, Wiesław Szulc and Beata Rutkowska

Agronomy 2021, 11(6), 1077; https://doi.org/10.3390/agronomy11061077 - 26 May 2021

Cited by 32 | Viewed by 4894

Abstract

Removing bottom sediment from water reservoirs and rivers can, on the one hand, be an effective method to restore lakes, and on the other—be used for plant production, ensuring the recycling of nutrients. The aim of this research was to evaluate the possibilities [...] Read more.

Removing bottom sediment from water reservoirs and rivers can, on the one hand, be an effective method to restore lakes, and on the other—be used for plant production, ensuring the recycling of nutrients. The aim of this research was to evaluate the possibilities of using various types of bottom sediment and its impact on heavy metal content in soil and plants. For this purpose, a pot experiment was carried out using white mustard (Sinapis alba) as a test plant. The total content of heavy metals (Cd, Cu, Zn, Pb) was determined in soil and plant. The addition of all types of bottom sediment increased heavy metal content in the soil. The results indicate that adding bottom sediment resulted in a significant increase in plant yield in comparison to the control. The highest yield as a result of direct effect was obtained for a combination with a 5% addition of dam sediment, while as a result of residual effect, the highest yield was achieved for a mixture with a 10% addition of pond sediment. The values of the transfer factor (TF = Cplant/Csoil) indicate a high accumulation of zinc and low accumulation of lead in the plant. Full article

(This article belongs to the Special Issue Heavy Metal Pollution and Its Effects on Agriculture)

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13 pages, 2048 KiB

Open AccessEditor’s ChoiceArticle

Comparing the Life Table and Population Projection of Gaeolaelaps aculeifer and Stratiolaelaps scimitus (Acari: Laelapidae) Based on the Age-Stage, Two-Sex Life Table Theory

by Jihye Park, Md Munir Mostafiz, Hwal-Su Hwang, Duck-Oung Jung and Kyeong-Yeoll Lee

Agronomy 2021, 11(6), 1062; https://doi.org/10.3390/agronomy11061062 - 25 May 2021

Cited by 7 | Viewed by 3792

Abstract

Predatory soil-dwelling mites, Gaeolaelaps aculeifer (Canestrini) and Stratiolaelaps scimitus (Womersley) (Mesostigmata: Laelapidae), are essential biocontrol agents of small soil arthropod pests. To understand the population characteristics of these two predatory mites, we investigated their development, survival, and fecundity under laboratory conditions. We used [...] Read more.

Predatory soil-dwelling mites, Gaeolaelaps aculeifer (Canestrini) and Stratiolaelaps scimitus (Womersley) (Mesostigmata: Laelapidae), are essential biocontrol agents of small soil arthropod pests. To understand the population characteristics of these two predatory mites, we investigated their development, survival, and fecundity under laboratory conditions. We used Tyrophagus putrescentiae (Schrank) as a food source and analyzed the data using the age-stage, two-sex life table. The duration from egg to adult for G. aculeifer was longer than that for S. scimitus, but larval duration was similar between the two species. Notably, G. aculeifer laid 74.88 eggs/female in 24.50 days, but S. scimitus laid 28.46 eggs/female in 19.1 days. Several population parameters, such as the intrinsic rate of increase, finite rate of increase, net reproductive rate, and gross reproductive rate of G. aculeifer, were significantly higher than those of S. scimitus. Using the bootstrap technique with 100,000 samples, we demonstrated that the life tables constructed based on the 2.5th and 97.5th percentiles of finite rate of increase (λ) net reproductive rate (R₀) may characterize the variability in the survival and fecundity curves, as well as predict population growth uncertainty. These data provide important information for the practical application of predatory soil mites to manage agricultural pests. Full article

(This article belongs to the Special Issue Integrated Pest Management and Biological Control in Commercial Orchards)

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10 pages, 1213 KiB

Open AccessEditor’s ChoiceCommunication

Sacha Inchi (Plukenetia volubilis L.) Is an Underutilized Crop with a Great Potential

by Nete Kodahl and Marten Sørensen

Agronomy 2021, 11(6), 1066; https://doi.org/10.3390/agronomy11061066 - 25 May 2021

Cited by 48 | Viewed by 15753

Abstract

Plukenetia volubilis (Euphorbiaceae) is an underutilized oilseed crop native to the Amazon basin, where it has been utilized by humans since Incan times. The large seeds contain approximately 45–50% lipid, of which approximately 35.2–50.8% is α-linolenic acid (C18:3 n-3, ω-3) and approximately 33.4–41.0% [...] Read more.

Plukenetia volubilis (Euphorbiaceae) is an underutilized oilseed crop native to the Amazon basin, where it has been utilized by humans since Incan times. The large seeds contain approximately 45–50% lipid, of which approximately 35.2–50.8% is α-linolenic acid (C18:3 n-3, ω-3) and approximately 33.4–41.0% is linoleic acid (C18:2 n-6, ω-6), the two essential fatty acids required by humans. The seeds also contain 22–30% protein and have antioxidant properties. Due to its excellent nutritional composition and good agronomic properties, it has attracted increasing attention in recent years, and cultivation is expanding. When considering current global challenges, a reformation of our food systems is imperative in order to ensure food security, mitigation of climate change, and alleviation of malnutrition. For this purpose, underutilized crops may be essential tools which can provide agricultural hardiness, a reduced need for external inputs, climate resilience, diet diversification, and improved income opportunities for smallholders. Plukenetia volubilis is a promising up and coming crop in this regard and has considerable potential for further domestication; it has an exceptional oil composition, good sensory acceptability, is well suited for cultivation, and has numerous potential applications in, e.g., gastronomy, medicine, and cosmetics. Full article

(This article belongs to the Special Issue Using Our Agrobiodiversity: Plant-Based Solutions to Feed the World)

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9 pages, 3922 KiB

Open AccessEditor’s ChoiceArticle

New Technology for Desert Locust Control

by Graham A. Matthews

Agronomy 2021, 11(6), 1052; https://doi.org/10.3390/agronomy11061052 - 24 May 2021

Cited by 23 | Viewed by 6132

Abstract

Locust outbreaks usually begin in remote unpopulated areas following higher than average rainfall. The need to survey such areas has suggested that unmanned aerial vehicles (UAVs), often referred to as drones, might be a suitable means of surveying areas with suitable detection devices [...] Read more.

Locust outbreaks usually begin in remote unpopulated areas following higher than average rainfall. The need to survey such areas has suggested that unmanned aerial vehicles (UAVs), often referred to as drones, might be a suitable means of surveying areas with suitable detection devices to survey areas and detect important locust concentrations. This would facilitate determining where sprays need to be applied at this early stage and would minimise the risk of swarms developing and migrating to feed on large areas of crops. Ideally, a drone could also spray groups of hoppers and adults at this stage. To date, tests have shown limitations in their use to apply sprays, although it has been suggested that using a fleet of drones might be possible. The use of biopesticide in these areas has the advantage of being more environmentally acceptable as the spray has no adverse impact on birds. Full article

(This article belongs to the Special Issue How to Manage Migratory Pests and Potential Food Crises: Locusts Plagues in the 2020’s)

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18 pages, 9178 KiB

Open AccessEditor’s ChoiceArticle

Overexpression of GhMPK3 from Cotton Enhances Cold, Drought, and Salt Stress in Arabidopsis

by Salisu Bello Sadau, Adeel Ahmad, Sani Muhammad Tajo, Sani Ibrahim, Bello Babatunde Kazeem, Hengling Wei and Shuxun Yu

Agronomy 2021, 11(6), 1049; https://doi.org/10.3390/agronomy11061049 - 24 May 2021

Cited by 25 | Viewed by 3456

Abstract

Cotton production is hampered by a variety of abiotic stresses that wreak havoc on the growth and development of plants, resulting in significant financial losses. According to reports, cotton production areas have declined around the world as a result of the ongoing stress. [...] Read more.

Cotton production is hampered by a variety of abiotic stresses that wreak havoc on the growth and development of plants, resulting in significant financial losses. According to reports, cotton production areas have declined around the world as a result of the ongoing stress. Therefore, plant breeding programs are concentrating on abiotic stress-tolerant cotton varieties. Mitogen-activated protein kinase (MAPK) cascades are involved in plant growth, stress responses, and the hormonal signaling pathway. In this research, three abiotic stresses (cold, drought, and salt) were analyzed on GhMPK3 transformed Arabidopsis plants. The transgenic plant’s gene expression and morphologic analysis were studied under cold, drought, and salt stress. Physiological parameters such as relative leaf water content, excised leaf water loss, chlorophyll content, and ion leakage showed that overexpressed plants possess more stable content under stress conditions compared with the WT plants. Furthermore, GhMPK3 overexpressed plants had greater antioxidant activities and weaker oxidant activities. Silencing GhMPK3 in cotton inhibited its tolerance to drought stress. Our research findings strongly suggest that GhMPK3 can be regarded as an essential gene for abiotic stress tolerance in cotton plants. Full article

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

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16 pages, 556 KiB

Open AccessEditor’s ChoiceArticle

Regulated Salinity Eustress in a Floating Hydroponic Module of Sequentially Harvested Lettuce Modulates Phytochemical Constitution, Plant Resilience, and Post-Harvest Nutraceutical Quality

by Petronia Carillo, Georgios A. Soteriou, Marios C. Kyriacou, Maria Giordano, Giampaolo Raimondi, Francesco Napolitano, Emilio Di Stasio, Ida Di Mola, Mauro Mori and Youssef Rouphael

Agronomy 2021, 11(6), 1040; https://doi.org/10.3390/agronomy11061040 - 22 May 2021

Cited by 20 | Viewed by 3489

Abstract

A mild salinity stress (eustress) may modulate the induction of the plant defense system in horticultural crops and the synthesis of phytochemical components able to enhance plant resilience, post-harvest performance, and the nutraceutical quality of produce. However, the choice of the correct eustress [...] Read more.

A mild salinity stress (eustress) may modulate the induction of the plant defense system in horticultural crops and the synthesis of phytochemical components able to enhance plant resilience, post-harvest performance, and the nutraceutical quality of produce. However, the choice of the correct eustress type and dose to induce the synthesis of these protective phytochemicals is pivotal to avoid potential interference with plant growth and productivity. In order to study how green and red lettuce (Lactuca sativa L.) plants equilibrate the nutritional and nutraceutical components of quality with yield components, we applied iso-osmotic concentrations of three different salts (20 mM NaCl, 20 mM KCl, and 13.3 mM CaCl₂, with a final total ionic concentration of 40 mM) in combination with two successive harvests in a floating raft system. The biometric parameters, mineral composition, bioactive compounds, and antioxidant activity of both cultivars were analyzed. The green cultivar had a superior response concerning biometric traits and productivity compared to the red one during the first cut but lower phytochemical content (e.g., ascorbic acid). The effect of cut order, independently of cultivar and salinity treatments, demonstrated that at the first harvest plants could redirect metabolism by increasing the lipophilic antioxidant content (LAA) at the expense of plant yield, therefore increasing plant resilience and post-harvest nutraceutical quality; whereas, at the second harvest, plants reverted principally to tissue expansion. The treatments with iso-osmotic salt concentrations did not affect K and Mg ion contents but further increased LAA and resulted only in a moderate decrease of fresh yield. The lettuce nitrate content was reduced during the second cut only when lettuce plants were treated with NaCl and especially CaCl₂. Full article

(This article belongs to the Special Issue The Tripartite of Soilless Systems, Growing Media, and Plants through An Intensive Crop Production Scheme)

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18 pages, 2097 KiB

Open AccessEditor’s ChoiceArticle

Protein Hydrolysates and Mo-Biofortification Interactively Modulate Plant Performance and Quality of ‘Canasta’ Lettuce Grown in a Protected Environment

by Leo Sabatino, Beppe Benedetto Consentino, Youssef Rouphael, Claudio De Pasquale, Giovanni Iapichino, Fabio D’Anna and Salvatore La Bella

Agronomy 2021, 11(6), 1023; https://doi.org/10.3390/agronomy11061023 - 21 May 2021

Cited by 40 | Viewed by 3347

Abstract

Since the use of protein hydrolysates (PHs) enhances overall plant performance and quality of vegetables, they might be considered as a toll to face a number of concerns essentially associated to the growing request of premium quality foodstuff realized in agreement with eco-friendly [...] Read more.

Since the use of protein hydrolysates (PHs) enhances overall plant performance and quality of vegetables, they might be considered as a toll to face a number of concerns essentially associated to the growing request of premium quality foodstuff realized in agreement with eco-friendly agriculture practices. Molybdenum (Mo) is considered a fundamental trace element for human body. Thus, its shortage determines several disorders mainly related to neurological lesion and esophageal cancer. Biofortification of fruiting and leafy vegetables is a promising tool to prevent Mo deficiency in the human diet. The current study was carried out to assess the interactive effect of plant-derived PHs and Mo dosage (0.0, 0.5, 3.0, and 6.0 µmol L⁻¹) on yield, morphology, nutritional and functional features, and nitrogen indices of ‘Canasta’ lettuce. Head fresh weight (HFW), head height (HH), ascorbic acid, K, Mg, total chlorophyll, as well as nitrogen use efficiency (NUE) index were positively correlated to PHs application. Furthermore, ascorbic acid and total chlorophyll were also improved by Mo supply. A great improvement in terms of soluble solid content (SSC), total sugars, total phenolic, carotenoids, Mo and N concentrations, nitrogen uptake efficiency (UE), and nitrogen physiological efficiency (PUE) indices was recorded when PHs application was combined with the highest Mo dosage (6.0 µmol L⁻¹). Consequently, our results suggest that Mo-biofortification and PHs application can positively modulate ‘Canasta’ lettuce plant performance and quality. Full article

(This article belongs to the Special Issue Toward Sustainability in Horticultural Crop Production Systems)

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16 pages, 1584 KiB

Open AccessEditor’s ChoiceArticle

Urea-Doped Calcium Phosphate Nanoparticles as Sustainable Nitrogen Nanofertilizers for Viticulture: Implications on Yield and Quality of Pinot Gris Grapevines

by Federica Gaiotti, Marco Lucchetta, Giacomo Rodegher, Daniel Lorenzoni, Edoardo Longo, Emanuele Boselli, Stefano Cesco, Nicola Belfiore, Lorenzo Lovat, José Manuel Delgado-López, Francisco J. Carmona, Antonietta Guagliardi, Norberto Masciocchi and Youry Pii

Agronomy 2021, 11(6), 1026; https://doi.org/10.3390/agronomy11061026 - 21 May 2021

Cited by 42 | Viewed by 5328

Abstract

In recent years, the application of nanotechnology for the development of new “smart fertilizers” is regarded as one of the most promising solutions for boosting a more sustainable and modern grapevine cultivation. Despite showing interesting potential benefits over conventional fertilization practices, the use [...] Read more.

In recent years, the application of nanotechnology for the development of new “smart fertilizers” is regarded as one of the most promising solutions for boosting a more sustainable and modern grapevine cultivation. Despite showing interesting potential benefits over conventional fertilization practices, the use of nanofertilizers in viticulture is still underexplored. In this work, we investigated the effectiveness of non-toxic calcium phosphate nanoparticles (Ca₃(PO₄)₂∙nH₂O) doped with urea (U-ACP) as a nitrogen source for grapevine fertilization. Plant tests were performed for two years (2019–2020) on potted adult Pinot gris cv. vines grown under semi-controlled conditions. Four fertilization treatments were compared: N1: commercial granular fertilization (45 kg N ha⁻¹); N2: U-ACP applied in fertigation (36 kg N ha⁻¹); N3: foliar application of U-ACP (36 kg N ha⁻¹); C: control, receiving no N fertilization. Plant nitrogen status (SPAD), yield parameters as well as those of berry quality were analyzed. Results here presented clearly show the capability of vine plants to recognize and use the nitrogen supplied with U-ACP nanoparticles either when applied foliarly or to the soil. Moreover, all of the quali–quantitative parameters measured in vine plants fed with nanoparticles were perfectly comparable to those of plants grown in conventional condition, despite the restrained dosage of nitrogen applied with the nanoparticles. Therefore, these results provide both clear evidence of the efficacy of U-ACP nanoparticles as a nitrogen source and the basis for the development of alternative nitrogen fertilization strategies, optimizing the dosage/benefit ratio and being particularly interesting in a context of a more sustainable and modern viticulture. Full article

(This article belongs to the Special Issue Sustainable Viticulture Production and Vineyard Management Practices)

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12 pages, 1822 KiB

Open AccessEditor’s ChoiceArticle

Antioxidant Activity and Phytochemical Content of Nine Amaranthus Species

by Jun-Hyoung Bang, Kyung Jun Lee, Won Tea Jeong, Seahee Han, Ick-Hyun Jo, Seong Ho Choi, Hyunwoo Cho, Tae Kyung Hyun, Jeehye Sung, Junsoo Lee, Yoon-Sup So and Jong-Wook Chung

Agronomy 2021, 11(6), 1032; https://doi.org/10.3390/agronomy11061032 - 21 May 2021

Cited by 30 | Viewed by 6033

Abstract

Amaranthus species are widely used as grain and leaf vegetables around the world and are potential dietary sources of antioxidants and phenolic compounds. In this study, we examined the variation in total flavonoid contents, total polyphenol contents, and antioxidant activities among 120 accessions [...] Read more.

Amaranthus species are widely used as grain and leaf vegetables around the world and are potential dietary sources of antioxidants and phenolic compounds. In this study, we examined the variation in total flavonoid contents, total polyphenol contents, and antioxidant activities among 120 accessions of nine Amaranthus species. The antioxidant activity of DPPH (2,2-diphenyl-1-picrylhydrazyl) of the 120 amaranth accessions ranged from 1.1 (A. tricolor) to 75.2 (A. tricolor mg ascorbic acid equivalents (AAE)/g in 2018, and 8.5 (A. tricolor) to 68.8 (A. dubius) mg AAE/g in 2019. ABTS (2,2′-azinobis (3-ethylbenzothiazoline 6-sulfonate)) antioxidant activity ranged from 16.7 (A. tricolor) to 78.3 (A. hypochondriacus) mg AAE/g in 2018, and 36.6 (A. tricolor) to 79.2 (A. dubius) mg AAE/g in 2019. Total flavonoid content (TFC) of 2018 and 2019 ranged from 21.7 (A. caudatus) to 52.7 (A. hybridus) and from 22.3 (A. viridis) to 54.7 (A. tricolor), respectively Antioxidant activities were compared using two methods and all components were measured in plants grown both in 2018 and 2019. We identified wide variation among the accessions and between plants grown in the two years. Antioxidant activities and phytochemical contents were consistently negatively correlated. The nine species and 120 accessions clustered into three groups according to their antioxidant activities, total flavonoid contents, and total polyphenol contents in each year. These results provide information about the nutritional profiles of different Amaranthus species. Full article

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14 pages, 2685 KiB

Open AccessEditor’s ChoiceArticle

Effects of Manure and Chemical Fertilizer on Bacterial Community Structure and Soil Enzyme Activities in North China

by Zhiping Liu, Wenyan Xie, Zhenxing Yang, Xuefang Huang and Huaiping Zhou

Agronomy 2021, 11(5), 1017; https://doi.org/10.3390/agronomy11051017 - 20 May 2021

Cited by 31 | Viewed by 4321

Abstract

The application of organic fertilizer affects soil microbes and enzyme activities. In this study, we explored the effects of various long-term different fertilization treatments (manure, M; chemical fertilizer, NP; manure + chemical fertilizer, MNP; and no fertilizer, CK) on bacterial community structure and [...] Read more.

The application of organic fertilizer affects soil microbes and enzyme activities. In this study, we explored the effects of various long-term different fertilization treatments (manure, M; chemical fertilizer, NP; manure + chemical fertilizer, MNP; and no fertilizer, CK) on bacterial community structure and soil sucrase, urease, and alkaline phosphatase activities in Shaping, Hequ, China. High-throughput sequencing was used to amplify the third to the fourth hypervariable region of the 16S ribosomal RNA for analysis of the bacterial community structure. Enzyme activities were determined by colorimetry. Soil treated with MNP had the highest bacterial Abundance-based Coverage Estimator index and enzyme activities. The principal coordinates analysis results showed significant differences among the various fertilization treatments (p < 0.001). Proteobacteria, Actinobacteria, Acidobacteria, Gemmatimonadetes, and Chloroflexi were consistently dominant in all soil samples. The redundancy analysis and Monte Carlo permutation tests showed that the soil bacterial communities were significantly correlated with alkali-hydrolyzable nitrogen, organic matter, urease, and alkaline phosphatase. Our results reveal the fundamentally different effects that organic and inorganic fertilizers have on soil bacterial communities and their functions. Full article

(This article belongs to the Special Issue Soil Microbes and Nutrient Recycling in Agroecosystems)

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18 pages, 1488 KiB

Open AccessEditor’s ChoiceArticle

Cycling Phosphorus and Nitrogen through Cropping Systems in an Intensive Dairy Production Region

by April B. Leytem, Paula Williams, Shan Zuidema, Audrey Martinez, Yen Leng Chong, Alyssa Vincent, Aaron Vincent, Daniel Cronan, Andrew Kliskey, J. D. Wulfhorst, Lilian Alessa and David Bjorneberg

Agronomy 2021, 11(5), 1005; https://doi.org/10.3390/agronomy11051005 - 19 May 2021

Cited by 22 | Viewed by 4271

Abstract

As pressure on the dairy industry to reduce its environmental impact increases, efficient recycling of manure nutrients through local cropping systems becomes crucial. The aim of this study was to calculate annual nitrogen (N) and phosphorus (P) budgets in six counties located in [...] Read more.

As pressure on the dairy industry to reduce its environmental impact increases, efficient recycling of manure nutrients through local cropping systems becomes crucial. The aim of this study was to calculate annual nitrogen (N) and phosphorus (P) budgets in six counties located in the Magic Valley, Idaho and estimate what distance manure would need to be transported to be in balance with crop nutrient demand given current dairy cattle populations and cropping systems. Our analysis suggests that crop N needs will not be met solely by manure, and synthetic fertilizer will need to be applied. However, to balance P with crop production, manure would need to be transported a minimum of 12.9 km from dairies and would have to replace synthetic fertilizer P on 91% of regional cropland. Education of producers and technical specialists would be necessary to improve the management of manure use in regional cropping systems. Technical solutions such as alternative diets for cattle and nutrient capture from manure streams will also likely be necessary to bring regional P into balance to protect environmental quality and improve the sustainability of the regional dairy industry. Full article

(This article belongs to the Special Issue Managing Nutrient Balances in Agriculture - Agronomy, Animal Manure and the Circularity of Nitrogen and Phosphorus)

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23 pages, 5223 KiB

Open AccessEditor’s ChoiceArticle

Climate Projections for Precipitation and Temperature Indicators in the Douro Wine Region: The Importance of Bias Correction

by Joana Martins, Helder Fraga, André Fonseca and João Andrade Santos

Agronomy 2021, 11(5), 990; https://doi.org/10.3390/agronomy11050990 - 17 May 2021

Cited by 32 | Viewed by 3951

Abstract

The implications of weather and climate extremes on the viticulture and winemaking sector can be particularly detrimental and acquire more relevance under a climate change context. A four-member ensemble of the Regional Climate Model-Global Climate Model chain simulations is used to evaluate the [...] Read more.

The implications of weather and climate extremes on the viticulture and winemaking sector can be particularly detrimental and acquire more relevance under a climate change context. A four-member ensemble of the Regional Climate Model-Global Climate Model chain simulations is used to evaluate the potential impacts of climate change on indices of extreme temperature and precipitation, as well as on agroclimatic indices of viticultural suitability in the Douro Wine Region, Portugal, under current and future climate conditions, following the RCP8.5 anthropogenic radiative forcing scenario. Historical (1989–2005) and future (2051–2080) periods are considered for this purpose. Although model outputs are bias-corrected to improve the accuracy of the results, owing to the sensitivity of the climatic indicators to the specific bias correction method, the performance of the linear and quantile mapping methods are compared. The results hint at the importance of choosing the most accurate method (quantile mapping), not only in replicating extremes events but also in reproducing the accumulated agroclimatic indices. Significant differences between the bias correction methods are indeed found for the number of extremely warm days (maximum temperature > 35 °C), number of warm spells, number of warm spell days, number of consecutive dry days, the Dryness Index, and growing season precipitation. The Huglin Index reveals lower sensitivity, thus being more robust to the choice of the method. Hence, an unsuitable bias correction method may hinder the accuracy of climate change projections in studies heavily relying on derived extreme indices and agroclimatic indicators, such as in viticulture. Regarding the climate change signal, significant warming and drying trends are projected throughout the target region, which is supported by previous studies, but also accompanied by an increase of intensity, frequency, and duration of extreme events, namely heatwaves and dry spells. These findings thereby corroborate the need to adopt timely and effective adaptation strategies by the regional winemaking sector to warrant its future sustainability and enhance climate resilience. Full article

(This article belongs to the Section Agricultural Biosystem and Biological Engineering)

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14 pages, 1553 KiB

Open AccessEditor’s ChoiceArticle

Life Cycle Assessment of Biomass Production from Lignocellulosic Perennial Grasses under Changing Soil Nitrogen and Water Content in the Mediterranean Area

by Danilo Scordia, Giuseppina Marina D’Agosta, Mariadaniela Mantineo, Giorgio Testa and Salvatore Luciano Cosentino

Agronomy 2021, 11(5), 988; https://doi.org/10.3390/agronomy11050988 - 16 May 2021

Cited by 4 | Viewed by 2634

Abstract

Low iLUC risk feedstocks, such as lignocellulosic no-food crops, have been indicated as sustainable crops for the transition to a bio-based economy. Given the high output to input ratio and the environmental benefits that can be obtained from renewable heat production replacing fossil [...] Read more.

Low iLUC risk feedstocks, such as lignocellulosic no-food crops, have been indicated as sustainable crops for the transition to a bio-based economy. Given the high output to input ratio and the environmental benefits that can be obtained from renewable heat production replacing fossil fuels, the present study addressed the biomass yield, CO₂-sequestration, and life cycle assessment of giant reed (Arundo donax L.) and miscanthus (Miscanthus × giganteus Greef et Deuter) growing under different soil water availability and nitrogen fertilization for three consecutive growing seasons in a semiarid Mediterranean environment. Giant reed outperformed miscanthus, showed a higher CO₂-sequestration and a lower overall environmental impact. In case of both crops, the irrigation effect was significant, while the one of nitrogen fertilization was not apparent. While giant reed responded positively to reduced irrigation, compared to its highest level, as the plantation became older, miscanthus needed high water volume to get most out its potential yield. Nonetheless, the growing season had also a significant effect on both crops, mainly when low yields were achieved following the establishment year. Unlike the environmental benefits in the impact categories “non-renewable energy use” and “global warming potential”, environmental burdens concerning ozone depletion, acidification, and eutrophication were observed, indicating that further improvements of the evaluation of impact assessment associated with bioenergy production might be necessary. Full article

(This article belongs to the Special Issue Insights into Agronomic Practices for a Sustainable Exploitation of Bioenergy Perennial Grasses)

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15 pages, 289 KiB

Open AccessEditor’s ChoiceArticle

Factors That Determine Innovation in Agrifood Firms

by Juan Sebastián Castillo-Valero and María Carmen García-Cortijo

Agronomy 2021, 11(5), 989; https://doi.org/10.3390/agronomy11050989 - 16 May 2021

Cited by 5 | Viewed by 3390

Abstract

In this study, we aim to find the determinants of innovation in the agrifood industry in an inland region in southeast Spain, which depends upon and specializes in this sector. The determinants we propose are firm and environmental factors. From the empirical analyses [...] Read more.

In this study, we aim to find the determinants of innovation in the agrifood industry in an inland region in southeast Spain, which depends upon and specializes in this sector. The determinants we propose are firm and environmental factors. From the empirical analyses based on Box–Cox models, we deduce that a firm’s internal factors or characteristics are those that have the greatest influence on its propensity to innovate. Among them, firm size has the greatest effect. Innovation culture has the potential for exerting a multiplying effect via mechanisms such as knowledge spillovers or learning by doing. Full article

(This article belongs to the Special Issue Farmers’ Adoption of Agricultural Innovations and Their Impact)

15 pages, 2220 KiB

Open AccessEditor’s ChoiceArticle

Carvacrol: A Promising Environmentally Friendly Agent to Fight Seeds Damping-Off Diseases Induced by Fungal Species

by Hamza Saghrouchni, Azeddin El Barnossi, Ahmad Mohammad Salamatullah, Mohammed Bourhia, Abdulhakeem Alzahrani, Mohammed Saeed Alkaltham, Heba Khalil Alyahya, Nour El Houda Tahiri, Hamada Imtara and Işıl Var

Agronomy 2021, 11(5), 985; https://doi.org/10.3390/agronomy11050985 - 15 May 2021

Cited by 15 | Viewed by 3959

Abstract

Background: Gramineae damping-off disease is a growing problem worldwide, which affects a large range of seedlings in nurseries, glasshouses, gardens, crops, forests and untimely generates a heavy economic impact on the agriculture and related sectors. Objectives: The present study was conducted to evaluate [...] Read more.

Background: Gramineae damping-off disease is a growing problem worldwide, which affects a large range of seedlings in nurseries, glasshouses, gardens, crops, forests and untimely generates a heavy economic impact on the agriculture and related sectors. Objectives: The present study was conducted to evaluate the preventive potential of carvacrol on germination of Fusarium oxysporum, Neocosmospora solani, and Microdochium nivale spores as responsible agents for Lolium perenne seeds damping-off disease. Material and methods: Macrodilution method in agar medium, spore germination, spore destruction, and preventive treatment bioassays were used to achieve this goal. Results: The minimum inhibitory concentration (MIC) of carvacrol vs. tested strains existed in the range of 0.25–0.5 mg/mL. Carvacrol used in concentrations ranging from 0.2 to 0.4 mg/mL inhibited the germination of all fungal spores in a dose-dependent manner. Carvacrol showed a very strong sporicidal effect against all studied fungal strains, and this effect was well confirmed by microscopic observations. The percentage of growth inhibition was found to be strictly correlated to carvacrol dose up vs. all strains. Carvacrol increased the emergence of L. perenne seeds when compared to both uninfested and infested seeds. Conclusion: Based on the results obtained, carvacrol fulfills the requirement for being a natural alternative agent to fight Gramineae seedlings’ damping-off caused by fungal species without adverse effects on the plants. Full article

(This article belongs to the Special Issue Chemical Control of Fungal Diseases)

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16 pages, 1570 KiB

Open AccessEditor’s ChoiceArticle

Assessment of Conjugate Complexes of Chitosan and Urtica dioica or Equisetum arvense Extracts for the Control of Grapevine Trunk Pathogens

by Natalia Langa-Lomba, Laura Buzón-Durán, Pablo Martín-Ramos, José Casanova-Gascón, Jesús Martín-Gil, Eva Sánchez-Hernández and Vicente González-García

Agronomy 2021, 11(5), 976; https://doi.org/10.3390/agronomy11050976 - 14 May 2021

Cited by 26 | Viewed by 4777

Abstract

In the work presented herein, we analyze the efficacy of three basic substances that comply with European Regulation (EC) No 1107/2009, namely chitosan, horsetail (Equisetum arvense L.) and nettle (Urtica dioica L.), for the control of grapevine trunk diseases (GTDs) in [...] Read more.

In the work presented herein, we analyze the efficacy of three basic substances that comply with European Regulation (EC) No 1107/2009, namely chitosan, horsetail (Equisetum arvense L.) and nettle (Urtica dioica L.), for the control of grapevine trunk diseases (GTDs) in organic farming. The E. arvense and U. dioica aqueous extracts, prepared according to SANCO/12386/2013 and SANTE/11809/2016, have been studied by gas chromatography–mass spectrometry (GC-MS), identifying their main active constituents. The three basic substances, either alone or in combination (forming conjugate complexes), have been tested in vitro against eight Botryosphaeriaceae species, and in vivo, in grafted plants artificially inoculated with Neofusicoccum parvum and Diplodia seriata. A clear synergistic behavior between chitosan and the two plant extracts has been observed in the mycelial growth inhibition tests (resulting in EC₉₀ values as low as 208 μg·mL⁻¹ for some of the isolates), and statistically significant differences have been found in terms of vascular necroses lengths between treated and non-treated plants, providing further evidence of aforementioned synergism in the case of D. seriata. The reported data supports the possibility of extending the applications of these three basic substances in Viticulture beyond the treatment of mildew. Full article

(This article belongs to the Special Issue Potential of Biopesticides to Optimize Pest Control in Sustainable Crop Production)

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30 pages, 867 KiB

Open AccessEditor’s ChoiceArticle

Impact of the COVID-19 Pandemic on Agri-Food Companies in the Region of Extremadura (Spain)

by Beatriz Corchuelo Martínez-Azúa, Pedro Eugenio López-Salazar and Celia Sama-Berrocal

Agronomy 2021, 11(5), 971; https://doi.org/10.3390/agronomy11050971 - 13 May 2021

Cited by 23 | Viewed by 7716

Abstract

The coronavirus pandemic is having an economic impact, previously non-existent, on the world economy. The objective of this study is to analyze the impact of COVID-19 on agri-food companies in the region of Extremadura (Spain). A multiple-case study based on in-depth interviews was [...] Read more.

The coronavirus pandemic is having an economic impact, previously non-existent, on the world economy. The objective of this study is to analyze the impact of COVID-19 on agri-food companies in the region of Extremadura (Spain). A multiple-case study based on in-depth interviews was carried out in the period February 2020–January 2021. The results reveal the existence of negative and positive impacts, both financial (decrease in turnover; decrease/displacement in the demand for products; budget reduction in R&D projects; increase in certain product sales) and operational (difficulty in marketing activities, lack of staff, stoppage in company activity, and supply problems), depending, principally, on the nature of the products, the changes generated in consumer behavior, and mobility problems. Likewise, changes were observed in processes (search of clients in other markets, increased use of technology in communication and marketing activities, and development of new products) and procedures (reorganization of personnel activities, implementation of new health protocols) in companies to overcome the obstacles imposed by the new situation. In conclusion, the change in surrounding conditions, and the characteristics of the spread of the pandemic, have impacted on the strategies, behavior, processes, dynamics and results of organizations regardless of their size and the nature of their work product or service. Full article

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

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