Next Issue
Volume 11, August
Previous Issue
Volume 11, June

Agronomy, Volume 11, Issue 7 (July 2021) – 184 articles

Cover Story (view full-size image): The sugarcane emergence rate has a great influence on its yield, and planting quality is closely related to the emergence rate. At the present stage, the research is mainly focus on improving sowing qualification and decreasing sowing omission, but ignoring the ignoring the influence of covering quality on emergence. Some studies show that the covering quality of soil and film has enormously contributed to the germination and emergence rates of seed cane setts. This paper introduced a cane seed covering device suitable for a sugarcane transverse planter was designed, and explored the factors and laws affecting covering quality. The field tests were carried out to get the optimal parameter combination, and two emergence rates in standard covering and traditional covering were compared. The results showed a notable effect. View this paper
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:
Article
Effect of Ascophyllum nodosum Alga Application on Microgreens, Yield, and Yield Components in Oats Avena sativa L.
Agronomy 2021, 11(7), 1446; https://doi.org/10.3390/agronomy11071446 - 20 Jul 2021
Viewed by 965
Abstract
This paper describes the influence of Ascophyllum nodosum algae on the seeds, microgreens, yield, and yield components of oat Avena sativa cv. Bingo. This article includes the results from three experiments. In one of the experiments, the oat seeds were soaked in a [...] Read more.
This paper describes the influence of Ascophyllum nodosum algae on the seeds, microgreens, yield, and yield components of oat Avena sativa cv. Bingo. This article includes the results from three experiments. In one of the experiments, the oat seeds were soaked in a solution of demineralized water with dried comminuted and homogenized algae. For the FT–Raman spectra measurements, a spectrometer with an Nd:YAG laser, with a germanium detector, was used. The results obtained show that an excessively low as well as an excessively high alga concentration did not have an influence on the change in oat composition. Other algae concentrations that were used in these experiments caused significant chemical changes in the oat seeds. For the FT–Raman data, separation of the control from all the oat grains treated with different algae concentrations was possible. The aim of the pot experiment was to determine the effect of the application of algae (in different doses) on the A. sativa green mass of young plants (microgreens). The certified oat seeds, after being soaked in a solution with algae, were planted in the ground. For the chemometric analysis of the oat samples, a Fourier-transform infrared (FTIR) spectrometer device was used. The data were recorded with a viewing diamond with an attenuated total reflection (ATR) crystal plate. The FTIR spectra showed that soaking in an algae suspension affected the germination, general metabolism, and chemical composition of the oats. The use of algae did not change the lipid content of the plant. The three-year field experiment was established by introducing two factors: A. nodosum application (A) and a pre-sowing stimulation with a low-frequency magnetic field (S). The influence of experimental factors on the oat yield and its structure (yield structure components and yield components) was investigated. The beneficial effect of algae on oat yield was demonstrated by improved parameters such as the number and weight of the grains; however, under field conditions, the pre-sowing magnetic field stimulation of seeds did not have a beneficial effect. Various weather conditions also had a great influence on the yield. This study also considered the role of A. nodosum as a biostimulant in plants, and this showed potential under less favorable conditions. Full article
Show Figures

Figure 1

Article
Identification and Characterization of SPL Transcription Factor Family Reveals Organization and Chilling-Responsive Patterns in Cabbage (Brassica oleracea var. capitata L.)
Agronomy 2021, 11(7), 1445; https://doi.org/10.3390/agronomy11071445 - 20 Jul 2021
Viewed by 991
Abstract
Squamosa promoter-binding protein-like (SPL) is a major family of plant-specific transcription factor, which is involved in multiple biological processes, such as plant growth and development, hormone response, light response and stress response. Therefore, it has been profoundly significant to systematically analyze the SPL [...] Read more.
Squamosa promoter-binding protein-like (SPL) is a major family of plant-specific transcription factor, which is involved in multiple biological processes, such as plant growth and development, hormone response, light response and stress response. Therefore, it has been profoundly significant to systematically analyze the SPL Transcription Factors family in Brassica oleracea. In this study, a total of 33 BoSPLs were identified in the B. oleracea genome, and they were further divided into six subgroups based on the phylogenetic tree constructed from the SPL proteins of B. oleracea, B. rapa and Arabidopsis thaliana. The expression profile of BoSPLs in different organs/tissues showed that a large number of BoSPLs were expressed in the callus, root, stem, leaf, bud, flower and silique. In addition, the expression levels of two BoSPLs (BoSPL9b and BoSPL10b) were up-regulated in chilling tolerance cabbage ‘CT-923’ at 6 h after chilling stress when compared with normal treatment (mock), while two BoSPLs (BoSPL9b and BoSPL15a) in chilling sensitive cabbage ‘CS-D9’, five BoSPLs (BoSPL1, -9a, -9b, -10b, -11b) in ‘CT-923’ and two BoSPLs (BoSPL9b and BoSPL16a) in ‘CS-D9’ were up-regulated after 24 h chilling stress, indicated that these genes may play an important role in the chilling-tolerance of cabbage. We analyzed the characteristics of BoSPLs and provided the basis for further functional research. Full article
(This article belongs to the Special Issue Insights from Genetic Bioinformatics of Crops)
Show Figures

Figure 1

Article
Using Quinine as a Fluorescent Tracer to Estimate Overland Flow Velocities on Bare Soil: Proof of Concept under Controlled Laboratory Conditions
Agronomy 2021, 11(7), 1444; https://doi.org/10.3390/agronomy11071444 - 20 Jul 2021
Viewed by 728
Abstract
This study presents a tracer technique based on the fluorescent properties of quinine to help on the visualization of shallow flows and allow a quantitative measurement of overland flow velocities. Laboratory experiments were conducted to compare the traditional dye tracer and thermal tracer [...] Read more.
This study presents a tracer technique based on the fluorescent properties of quinine to help on the visualization of shallow flows and allow a quantitative measurement of overland flow velocities. Laboratory experiments were conducted to compare the traditional dye tracer and thermal tracer techniques with this novel fluorescent (quinine) tracer by injecting a quinine solution and the other tracers into shallow flowing surface water. The leading-edge tracer velocities, estimated using videos of the experiments with the quinine tracer were compared with the velocities obtained by using thermograms and real imaging videos of the dye tracers. The results show that the quinine tracer can be used to estimate both overland and rill flow velocities, since measurements are similar to those resulting from using other commonly used tracers. The main advantage of using the quinine tracer is the higher visibility of the injected tracer under ultraviolet A (UVA) light for low luminosity conditions. In addition, smaller amounts of quinine tracer are needed than for dye tracers, which lead to smaller disturbances in the flow. It requires a simple experimental setup and is non-toxic to the environment. Full article
(This article belongs to the Special Issue Application of Soil Sensing Technology in Irrigated Agricultural Land)
Show Figures

Figure 1

Article
Rebalance the Nutritional Status and the Productivity of High CaCO3-Stressed Sweet Potato Plants by Foliar Nourishment with Zinc Oxide Nanoparticles and Ascorbic Acid
Agronomy 2021, 11(7), 1443; https://doi.org/10.3390/agronomy11071443 - 20 Jul 2021
Cited by 7 | Viewed by 710
Abstract
The use of nano-fertilizers and antioxidants for specific crops to minimize the negative effect of abiotic stresses is imperative. Two field experiments were fulfilled during two summer seasons (2019 and 2020) to study the response of sweet potato (Beauregard cv.) plants grown in [...] Read more.
The use of nano-fertilizers and antioxidants for specific crops to minimize the negative effect of abiotic stresses is imperative. Two field experiments were fulfilled during two summer seasons (2019 and 2020) to study the response of sweet potato (Beauregard cv.) plants grown in calcareous soil (CaCO3 = 10.8–11.3%) to foliar nourishment with zinc oxide nanoparticles (ZnONPs) and ascorbic acid (ASA) applied individually or in a mixture. Both ZnONPs and ASA were applied in three doses: 0, 1000, or 1500 mg L−1 for ZnONPs, and 0, 250 and 500 mg L−1 for ASA. The highest values of iron (Fe) and manganese (Mn) contents were recorded in both seasons, while those of phosphorus (P) and copper (Cu) were recorded in the 2020 season with ZnONPs applied at 1500 mg L−1. Furthermore, in both seasons, the maximum values of nutrient contents, excluding Mn content, were obtained with ASA applied at 500 mg L−1. However, applying both ZnONPs and ASA in a mixture bypassed each applied alone, with the highest overall nutrient contents being recorded, with few exceptions, with the highest dose of the mixture. The trend of the tuber root nutrient contents was correlated with the corresponding values in the leaves. Maximum tuber root yield was obtained with foliar feeding with 1000 mg ZnONP and 250 mg ASA L−1 in both seasons. The resulting data recommend the use of foliar nourishment with fertilizer nanoparticles and antioxidants to enable stressed plants to collect appropriate nutrient contents from the defective soils. Full article
Show Figures

Figure 1

Article
Phenolics of Aerial Parts of Gentiana lutea L. and Their Biological Activity
Agronomy 2021, 11(7), 1442; https://doi.org/10.3390/agronomy11071442 - 20 Jul 2021
Cited by 2 | Viewed by 648
Abstract
Gentiana lutea L. is a medicinal plant the roots of which are primarily used in treatments of various human digestive disorders, but also the production of alcoholic liquors. The roots (radix) of G. lutea are described in the European Pharmacopeia, but knowledge about [...] Read more.
Gentiana lutea L. is a medicinal plant the roots of which are primarily used in treatments of various human digestive disorders, but also the production of alcoholic liquors. The roots (radix) of G. lutea are described in the European Pharmacopeia, but knowledge about the chemical composition and biological activities of its aerial parts is still limited. Thus, until today aerial parts of this species have not been used in medical treatments or consumed. Therefore, flowers, leaves, and stems extracts of G. lutea obtained by using four different extraction solvents (petrol ether, chloroform, ethanol, and water) were examined for their chemical composition and biological activities. High concentrations of salicylic acid, apigenin, and naringenin were recorded for ethanol stem extracts, while significant amounts of kaempferol were detected in leaves and flowers in chloroform and water extracts, respectively. The highest antioxidant potential was recorded for flower and stem petrol ether extracts with the lowest IC50 values, ranging from 94.46 ± 9.45 to 105.38 ± 10.54 μg/mL. Ethanol extracts of flowers and stems showed moderate antioxidant activity (IC50 143.15 ± 14.32 and 146.90 ± 14.69 μg/mL) as well as strong antimicrobial activity against Candida albicans (21.00 ± 1.00 and 27.50 ± 1.78 mm inhibition zones, respectively). In addition, ethanol extracts had higher antimycotic activity compared to naturally occurring phenolic compounds that are used as positive controls. Moreover, statistical analysis of the activities of plant extracts and single compounds showed that levels of chlorogenic and caffeic acids strongly correlate with the biological activities of the extracts, i.e., they are the main carriers of these biological activities. The presented results indicate the possible use of aerial parts of G. lutea as a natural preservative, as well as a antimicrobial agent, which significantly amplifies the benefits of this medicinal crop and greatly affects the sustainability of cultivated Gentiana plantation. Full article
Article
Botrytis cinerea Airborne Conidia and Their Germination Ability Assessed by Immunological Methods in a NW Spain Vineyard
Agronomy 2021, 11(7), 1441; https://doi.org/10.3390/agronomy11071441 - 20 Jul 2021
Cited by 1 | Viewed by 932
Abstract
Grey mould is a fungal disease responsible for important crop losses in most winemaking regions worldwide. In the present study, we developed immunological techniques for the detection and quantification of Botrytis cinerea conidia germinative material to obtain additional information about epidemic’s development on [...] Read more.
Grey mould is a fungal disease responsible for important crop losses in most winemaking regions worldwide. In the present study, we developed immunological techniques for the detection and quantification of Botrytis cinerea conidia germinative material to obtain additional information about epidemic’s development on the vineyard. The study was carried out in a northwest Spain vineyard during the grapevine flowering in 2017 and 2018. An aerobiological study was developed for the identification and quantification of Botrytis cinerea conidia. For the immunological analysis, we developed a specific protein extraction protocol and a standard curve to analyze the cyclone-trap samples by an indirect PTA-ELISA. The airborne B. cinerea protein concentrations showed a similar variation pattern than the airborne conidia concentrations in the atmosphere of the vineyard. We recorded a total of 5673 B. cinerea spores in 2017, and 7562 spores in 2018. Regarding the airborne protein concentrations, we detected 9.692 ng/m3 in 2017 and 7.715 ng/m3 in 2018. Based on the statistical influence of the considered variables, we developed a predictive model able to explain 40% of protein data variability. The resulting methodology based on the combination of immunological techniques and aerobiological monitoring leads to a more reasoned treatment schedule consistent with real phytosanitary vineyard conditions and a more effective responsiveness against the increasing variability associated to climate change on the crop-pathogen system. Full article
Show Figures

Figure 1

Review
Biofuel Benefit or Bummer? A Review Comparing Environmental Effects, Economics, and Feasibility of North American Native Perennial Grass and Traditional Annual Row Crops When Used for Biofuel
Agronomy 2021, 11(7), 1440; https://doi.org/10.3390/agronomy11071440 - 20 Jul 2021
Cited by 1 | Viewed by 923
Abstract
While biofuels have been touted as a benefit for growers—with the ability to be planted on marginal lands, for improved wildlife habitat, to sustain soils, and to reduce runoff—there remains to be a general summary of how beneficial they really are. This paper [...] Read more.
While biofuels have been touted as a benefit for growers—with the ability to be planted on marginal lands, for improved wildlife habitat, to sustain soils, and to reduce runoff—there remains to be a general summary of how beneficial they really are. This paper aims to review the environmental effects, feasibility, and economic aspects of using native perennial grasses in North America as biofuels as opposed to traditional annual crops. The Scopus database was used to search for manuscripts relating to each topic. In some instances, very few results appeared, so a second database, Digitop, was also used. Native perennial grasses have been found to sequester carbon and cultivating them can create a carbon sink in the soil. Overall, wildlife benefit more by having native perennial grass for biofuels planted than annual maize and having fewer harvests a season is better for wildlife over the entire year. Economically, growing native perennial grasses can be advantageous especially on marginal land, where it has a comparatively high yield. Although the second-generation biofuel supply chain is susceptible to changing market prices, it can be made more resilient and has advantages, for example resistance against the impacts of drought. Although there are many cultivars to choose from, factors like climate, soil, and genetics can provide pertinent information to match each specimen’s ideal growing conditions to the right location. Full article
(This article belongs to the Special Issue Biofuels and Bioenergy Contribute to Sustainable Global Development)
Article
Influence of Olive Maturity and Season on the Quality of Virgin Olive Oils from the Area Assigned to the Protected Designation of Origin of “Aceite de la Alcarria” (Spain)
Agronomy 2021, 11(7), 1439; https://doi.org/10.3390/agronomy11071439 - 20 Jul 2021
Cited by 1 | Viewed by 653
Abstract
This work aimed to assess the influence of olive maturity and oil season on the potential quality of monovarietal virgin olive oils from the area assigned to the Protected Designation of Origin of “Aceite de la Alcarria” (Spain), analysing the regulated physicochemical quality [...] Read more.
This work aimed to assess the influence of olive maturity and oil season on the potential quality of monovarietal virgin olive oils from the area assigned to the Protected Designation of Origin of “Aceite de la Alcarria” (Spain), analysing the regulated physicochemical quality and sensory parameters, the stability parameters and composition of fatty acids, sterols and triterpenic dialcohols. To complete the study, we also characterised the coupage olive oils made in the oil mills located in the PDO area (real quality). The main variety grown in La Alcarria is Castellana, whose oils are characterised by a high content of palmitic acid (14.27% with olives in veraison, 13.81% with ripe olives), a low content of linoleic acid (5.03% with olives in veraison, 5.98% with ripe olives) and a total phenol content higher than the rest of varieties grown in the area (between 350 and 500 mg of caffeic acid/kg depending on the season considered), which is reflected in higher oxidative stability values (induction time of 50.65 h at 100 °C). In addition, they have a sterol content below that established by the regulations (<1000 mg/kg). The olive oils produced using olives in veraison presented a lower level of acidity and peroxide index, more intense fruitiness, an absence of defects in all the samples and higher oxidative stability, compared to those produced using ripe olives, and thus early harvest of the olives is recommended. It was also found that the season affects the physicochemical composition of the oils, although these changes tend to be of little significance, with the characteristics of the variety being maintained, regardless of the harvesting season analysed. The coupage virgin olive oils produced in the mills registered under the PDO of Aceite de la Alcarria, representative of their real quality, showed, as expected, similar values to those observed in the monovarietal virgin olive oils produced using the Castellana variety, which is clearly predominant in the study area. The characterization of oils from local varieties allows one to obtain a greater variability in terms of the sensory notes of extra virgin olive oil. Full article
(This article belongs to the Special Issue Mediterranean Olive Trees and Olive Oil under Climate Change)
Show Figures

Figure 1

Article
Topographic Position, Land Use and Soil Management Effects on Soil Organic Carbon (Vineyard Region of Niš, Serbia)
Agronomy 2021, 11(7), 1438; https://doi.org/10.3390/agronomy11071438 - 20 Jul 2021
Cited by 1 | Viewed by 791
Abstract
Spatial distribution of soil organic carbon (SOC) is the result of a combination of various factors related to both the natural environment and anthropogenic activities. The aim of this study was to examine (i) the state of SOC in topsoil and subsoil of [...] Read more.
Spatial distribution of soil organic carbon (SOC) is the result of a combination of various factors related to both the natural environment and anthropogenic activities. The aim of this study was to examine (i) the state of SOC in topsoil and subsoil of vineyards compared to the nearest forest, (ii) the influence of soil management on SOC, (iii) the variation in SOC content with topographic position, (iv) the intensity of soil erosion in order to estimate the leaching of SOC from upper to lower topographic positions, and (v) the significance of SOC for the reduction of soil’s susceptibility to compaction. The study area was the vineyard region of Niš, which represents a medium-sized vineyard region in Serbia. About 32% of the total land area is affected, to some degree, by soil erosion. However, according to the mean annual soil loss rate, the total area is classified as having tolerable erosion risk. Land use was shown to be an important factor that controls SOC content. The vineyards contained less SOC than forest land. The SOC content was affected by topographic position. The interactive effect of topographic position and land use on SOC was significant. The SOC of forest land was significantly higher at the upper position than at the middle and lower positions. Spatial distribution of organic carbon in vineyards was not influenced by altitude, but occurred as a consequence of different soil management practices. The deep tillage at 60–80 cm, along with application of organic amendments, showed the potential to preserve SOC in the subsoil and prevent carbon loss from the surface layer. Penetrometric resistance values indicated optimum soil compaction in the surface layer of the soil, while low permeability was observed in deeper layers. Increases in SOC content reduce soil compaction and thus the risk of erosion and landslides. Knowledge of soil carbon distribution as a function of topographic position, land use and soil management is important for sustainable production and climate change mitigation. Full article
(This article belongs to the Section Farming Sustainability)
Show Figures

Figure 1

Article
Ammonium Excess Leads to Ca Restrictions, Morphological Changes, and Nutritional Imbalances in Tomato Plants, Which Can Be Monitored by the N/Ca Ratio
Agronomy 2021, 11(7), 1437; https://doi.org/10.3390/agronomy11071437 - 20 Jul 2021
Viewed by 736
Abstract
Both nitrogen and calcium fertilization management are vital for crops, where an imbalance of these elements can cause both physiological and yield problems. It has been proposed that nitrogen absorption, particularly ammonium, is in part dependent on calcium supply. Moreover, the balance between [...] Read more.
Both nitrogen and calcium fertilization management are vital for crops, where an imbalance of these elements can cause both physiological and yield problems. It has been proposed that nitrogen absorption, particularly ammonium, is in part dependent on calcium supply. Moreover, the balance between these two nutrients could be a key indicator of plant growth in some species. Tomato, one of the most cultivated crops worldwide, can also be widely affected by nutritional imbalance. Using large amounts of N fertilizers could lead to an imbalance with other nutrients and, thus, detrimental effects in terms of plant development and yield. Here we show that ammonium excess has a negative impact on plant development and results in calcium deficiency. Moreover, a deficit in calcium nutrition not only affects calcium concentration but also leads to a restriction in N uptake and reduced N concentration in the plant. These effects were evident at the seedling stage and also during flowering/fruit set. Using PCA analysis, we integrated both phenotypic and nutritional imbalances in seedlings and grown plants. Interestingly, the Ca/N ratio appears to be a key indicator to monitor appropriate N and calcium nutrition and more importantly the balance between both. Maintaining this balance could be an essential element for tomato crop production. Full article
Show Figures

Figure 1

Article
Canopy Temperature as a Key Physiological Trait to Improve Yield Prediction under Water Restrictions in Potato
Agronomy 2021, 11(7), 1436; https://doi.org/10.3390/agronomy11071436 - 20 Jul 2021
Cited by 3 | Viewed by 1426
Abstract
Canopy temperature (CT) as a surrogate of stomatal conductance has been highlighted as an essential physiological indicator for optimizing irrigation timing in potatoes. However, assessing how this trait could help improve yield prediction will help develop future decision support tools. In this study, [...] Read more.
Canopy temperature (CT) as a surrogate of stomatal conductance has been highlighted as an essential physiological indicator for optimizing irrigation timing in potatoes. However, assessing how this trait could help improve yield prediction will help develop future decision support tools. In this study, the incorporation of CT minus air temperature (dT) in a simple ecophysiological model was analyzed in three trials between 2017 and 2018, testing three water treatments under drip (DI) and furrow (FI) irrigations. Water treatments consisted of control (irrigated until field capacity) and two-timing irrigation based on physiological thresholds (CT and stomatal conductance). Two model perspectives were implemented based on soil water balance (P1) and using dT as the penalizing factor (P2), affecting the biomass dynamics and radiation use efficiency parameters. One of the trials was used for model calibration and the other two for validation. Statistical indicators of the model performance determined a better yield prediction at harvest for P2, especially under maximum stress conditions. The P1 and P2 perspectives showed their highest coefficient of determination (R2) and lowest root-mean-squared error (RMSE) under DI and FI, respectively. In the future, the incorporation of CT combining low-cost infrared devices/sensors with spatial crop models, satellite image information, and telemetry technologies, an adequate decision support system could be implemented for water requirement determination and yield prediction in potatoes. Full article
(This article belongs to the Special Issue Water Saving in Irrigated Agriculture)
Show Figures

Figure 1

Article
Assessment of Weed Classification Using Hyperspectral Reflectance and Optimal Multispectral UAV Imagery
Agronomy 2021, 11(7), 1435; https://doi.org/10.3390/agronomy11071435 - 19 Jul 2021
Cited by 6 | Viewed by 958
Abstract
Weeds compete with crops and are hard to differentiate and identify due to their similarities in color, shape, and size. In this study, the weed species present in sorghum (sorghum bicolor (L.) Moench) fields, such as amaranth (Amaranthus macrocarpus), pigweed [...] Read more.
Weeds compete with crops and are hard to differentiate and identify due to their similarities in color, shape, and size. In this study, the weed species present in sorghum (sorghum bicolor (L.) Moench) fields, such as amaranth (Amaranthus macrocarpus), pigweed (Portulaca oleracea), mallow weed (Malva sp.), nutgrass (Cyperus rotundus), liver seed grass (Urochoa panicoides), and Bellive (Ipomea plebeian), were discriminated using hyperspectral data and were detected and analyzed using multispectral images. Discriminant analysis (DA) was used to identify the most significant spectral bands in order to discriminate weeds from sorghum using hyperspectral data. The results demonstrated good separation accuracy for Amaranthus macrocarpus, Urochoa panicoides, Malva sp., Cyperus rotundus, and Sorghum bicolor (L.) Moench at 440, 560, 680, 710, 720, and 850 nm. Later, the multispectral images of these six bands were collected to detect weeds in the sorghum crop fields using object-based image analysis (OBIA). The results showed that the differences between sorghum and weed species were detectable using the six selected bands, with data collected using an unmanned aerial vehicle. Here, the highest spatial resolution had the highest accuracy for weed detection. It was concluded that each weed was successfully discriminated using hyperspectral data and was detectable using multispectral data with higher spatial resolution. Full article
Show Figures

Figure 1

Article
Spatial Distribution and Development of Sequential Sampling Plans for Diaphorina citri Kuwayama (Hemiptera: Liviidae)
Agronomy 2021, 11(7), 1434; https://doi.org/10.3390/agronomy11071434 - 19 Jul 2021
Viewed by 794
Abstract
Vector control in huanglongbing management has been conducted on a calendar basis resulting in high production costs. We addressed this issue and proposed a sequential sampling plan to support decision making for intervention against Diaphorina citri Kuwayama, which is involved in the transmission [...] Read more.
Vector control in huanglongbing management has been conducted on a calendar basis resulting in high production costs. We addressed this issue and proposed a sequential sampling plan to support decision making for intervention against Diaphorina citri Kuwayama, which is involved in the transmission of the bacteria Candidatus Liberibacter asiaticus, associated with such lethal disease. We analyzed 3,264,660 records from samples gathered from the Mexican trapping program for the monitoring of D. citri; it included weekly inspection of 86,004 yellow sticky traps distributed in the country. Spatial distribution of the insect, estimation of a common k (kc), and sequential sampling plans based on Sequential Probability Ratio Test (SPRT) were determined. Taylor’s power law coefficients were ≥1 indicating aggregation in the spatial distribution of the insect. Common k ranged from 0.0183 to 0.2253 and varied independently of geographic zone or citrus species. We obtained 18 sequential sampling plans, one for each state. In the Average Sample Number (ASN) function, the minimal number of samples to make a decision ranged from 17 to 65. In the Operational Characteristic (OC) function, probabilities for a correct intervention at the threshold of 0.2 D. citri adults/trap in most cases were above 80%. In a field evaluation, the application of sampling plans yielded savings obtained by reduction in the number of interventions for insect control. Full article
(This article belongs to the Special Issue Citrus Production and Protection from Pests and Diseases)
Show Figures

Figure 1

Article
Soil Organic Carbon Changes for Croplands across China from 1991 to 2012
Agronomy 2021, 11(7), 1433; https://doi.org/10.3390/agronomy11071433 - 19 Jul 2021
Cited by 1 | Viewed by 834
Abstract
Accurate estimates of soil organic carbon (SOC) are critical for evaluating the impacts of crop and nutrient management practices on soil sustainability and global climate change. Temporal and spatial variations in topsoil (0–0.20 m) SOC were analyzed using 43,743 soil samples in China’s [...] Read more.
Accurate estimates of soil organic carbon (SOC) are critical for evaluating the impacts of crop and nutrient management practices on soil sustainability and global climate change. Temporal and spatial variations in topsoil (0–0.20 m) SOC were analyzed using 43,743 soil samples in China’s croplands. The soil database in our study was collected from the International Plant Nutrition Institute (IPNI) China Program. The results showed an increasing trend in SOC density (SOCD) for both grain and cash crops from 1991 to 2012. The average SOCD increased by 16.8, 17.4, 11.8 and 8.7% in the north central, northwest, southeast and southwest regions, respectively, whereas average SOCD decreased by 1.3% for the northeast region between the 1991–2001 and 2002–2012 periods. For both grain and cash crops, the SOCD frequency distribution (%) increased in the ranges of 10–20, 20–30 and 30–40 Mg C ha−1 from the 1991–2001 to the 2002–2012, but decreased in the ranges of 0–10 and 50–60 Mg C ha−1. Additionally, SOCD increased in most major soil types across China’s cropland regions, except in phaeozems, chernozems and umbrisols, where it decreased by 8.6–18.7% mainly due to water runoff, soil erosion, and low C input. The overall SOC stock (SOCS) in China’s cropland increased by 260 Tg C (23.7 Tg C yr−1) from 1991–2001 to 2002–2012, which was partially due to the increased crop residue return, improved fertilization and adopted conservation tillage over the period. This SOC increase represents a potential offset in carbon dioxide (CO2) emissions that could help reduce the overall net CO2 emissions in China. Full article
Show Figures

Figure 1

Article
Exogenous Application of Thiourea for Improving the Productivity and Nutritional Quality of Bread Wheat (Triticum aestivum L.)
Agronomy 2021, 11(7), 1432; https://doi.org/10.3390/agronomy11071432 - 18 Jul 2021
Cited by 3 | Viewed by 959
Abstract
Because it is a staple food, sustainable production of wheat is crucial for global food security. Arid and semi-arid regions are worst affected by climate change, which has resulted in poor productivity of different crops, including wheat. To this end, this study aimed [...] Read more.
Because it is a staple food, sustainable production of wheat is crucial for global food security. Arid and semi-arid regions are worst affected by climate change, which has resulted in poor productivity of different crops, including wheat. To this end, this study aimed to investigate the effect of foliage-applied thiourea on the growth, yield, and nutritional-quality-related traits of bread wheat. The treatments consisted of thiourea levels (control, 500, and 1000 mg L−1) factorally combined with two diverse wheat cultivars (Gandam-1 and Galaxy-2013) at different growth stages (tillering, booting, and heading) and was repeated over two years. The analysis of the data shows that thiourea treatments and the cultivars significantly (p ≤ 0.05) affected the growth, nutritional quality traits, and morphological traits, and the interaction of the two factors was also significant. Improvement in productivity and nutritional quality was observed from the application of thiourea in both cultivars. Galaxy-2013 performed best at 1000 mg L−1 thiourea application for both productivity- and nutritional-quality-related traits at the heading stage. In conclusion, exogenous application of thiourea improves the productivity and nutritional quality of wheat on sandy loam soils in semi-arid regions; however, for wider recommendations, more trials may be conducted across various agro-ecological regions. Full article
(This article belongs to the Special Issue Nutritional Quality of Crops)
Show Figures

Figure 1

Article
Characterization and Antimicrobial Properties of Essential Oils from Four Wild Taxa of Lamiaceae Family Growing in Apulia
Agronomy 2021, 11(7), 1431; https://doi.org/10.3390/agronomy11071431 - 18 Jul 2021
Cited by 20 | Viewed by 1192
Abstract
Four taxa of the Lamiaceae family growing in Apulia (Clinopodium suaveolens, Satureja montana subsp. montana, Thymbra capitata, and Salvia fruticosa subsp. thomasii) that had not been previously studied for their potential use in the food sector, were analyzed for [...] Read more.
Four taxa of the Lamiaceae family growing in Apulia (Clinopodium suaveolens, Satureja montana subsp. montana, Thymbra capitata, and Salvia fruticosa subsp. thomasii) that had not been previously studied for their potential use in the food sector, were analyzed for their essential oils (EOs) composition and antioxidant and antimicrobial properties against some microorganisms, isolated from bread and bakery products, including molds (Aspergillus niger, Penicillium roqueforti) and spore-forming bacteria (Bacillus amyloliquefaciens and Bacillus subtilis). Two different sites were considered for each plant species, and the strongest antimicrobial EOs, which were active against all of the microorganisms tested, were those from one S. montana subsp. montana sample (Sm2) and both T. capitata EOs (Tc1 and Tc2) with Minimal Inhibitory Concentration (MIC) values ranging between 0.093% and 0.375% (v/v) against molds, while higher values were registered for bacteria (0.75–1%). In particular, the biological activity of EOs from T. capitata and S. montana subsp. montana was maybe due to the high amount of thymol and carvacrol, which were also responsible for the highest antioxidant activity. S. fruticosa subsp. thomasii EOs had different chemical profiles but showed only a slight antibacterial effect and no antifungal activity. C. suaveolens showed no significant changes between EOs with an interesting antifungal activity (MIC 0.093%÷0.187% v/v), which may be due to the presence of pulegone. These plant species can be considered as promising sources of bioactive compounds to be exploited as biopreservatives in bread and bakery products mainly considering the low concentration needed to inhibit microorganism’s growth. Full article
Show Figures

Graphical abstract

Article
The Influence of Seed Production Environment on Seed Development and Quality of Soybean (Glycine max (L.) Merrill)
Agronomy 2021, 11(7), 1430; https://doi.org/10.3390/agronomy11071430 - 17 Jul 2021
Cited by 5 | Viewed by 1214
Abstract
The aim of the study was to determine the effect of seed production environment in Sri Lanka on seed development, maturation, and subsequent seed quality. The experiment was conducted at six production environments, three locations (Mahailluppalama (M1), Polonnaruwa (POL), and Aluttarama (ALU), over [...] Read more.
The aim of the study was to determine the effect of seed production environment in Sri Lanka on seed development, maturation, and subsequent seed quality. The experiment was conducted at six production environments, three locations (Mahailluppalama (M1), Polonnaruwa (POL), and Aluttarama (ALU), over two planting cycles (P1, P2). Seed development and maturation, seed and seedling quality characteristics were evaluated at five reproductive (R6, R7, R8, R8 + 5 and R8 + 10) maturity stages. The study infers that production environment at the late reproductive (LR) stage (R6–R8) was critical in determining the seed quality. If the LR stage coincided with cumulative rainfall (RF) over 100 mm or above 75% relative humidity (RH), categorized as wet environment, around 27.5 days was required for the completion of seed maturation compared with only 17.5 days in dry environment. Seed lots from dry environment during LR stage surpassed the minimum quality standards (75% final germination, germination index of 300, germination rate index of 25% per day, seedling vigor index of 2500 and 15 µmol/min/mg FW catalase activity) at maturity stage R7 onwards, while this only occurred at maturity stage R8 for wet environment. A significant negative correlation (r = −0.50 **) was observed between glucose content, antioxidant enzyme activities and germination percentage. In conclusion, the findings provide useful information for the expansion of areas for seed production in Sri Lanka. Full article
Show Figures

Graphical abstract

Article
Genome-Wide Investigation of Spliceosomal SM/LSM Genes in Wheat (Triticum aestivum L.) and Its Progenitors
Agronomy 2021, 11(7), 1429; https://doi.org/10.3390/agronomy11071429 - 17 Jul 2021
Viewed by 720
Abstract
The SSM/SLSM (spliceosomal Smith (SM)/SM-like (LSM)) genes are the central components of the spliceosome in eukaryotes, which play an important role in regulating RNA splicing, participating in diverse biological processes. Although it has been detected in Arabidopsis and rice etc. plants, the members [...] Read more.
The SSM/SLSM (spliceosomal Smith (SM)/SM-like (LSM)) genes are the central components of the spliceosome in eukaryotes, which play an important role in regulating RNA splicing, participating in diverse biological processes. Although it has been detected in Arabidopsis and rice etc. plants, the members and significance of the SSM/SLSM gene family in wheat are still not reported. In this study, we identified the SSM/SLSM genes in wheat and its progenitors at genome-scale, where 57 SSM/SLSM genes were identified in wheat, together with 41, 17and 19 found in Triticum dicoccoides, Triticum urartu, and Aegilops tauschii. Furthermore, their phylogenetic relationship, gene structures, conserved motifs, and cis-regulatory elements were systematically analyzed. By synteny analysis, good collinearity of SSM/SLSM genes was found among bread wheat and its progenitors’ genomes, and the distribution of SMD2 genes in wheat chromosome 5A, 4B and 4D located in the 4AL-5AL-7BS chromosome model, due to the translocation. Then, the positively selected genes were further investigated based on the non-synonymous to synonymous (dN/dS) analysis of the orthologous pairs. Finally, the expression profiles of the SSM/SLSM genes were detected using RNA-seq datasets, and eight stress-responsive candidate genes were selected to validate their expression through qPCR (real-time quantitative polymerase chain reaction). According to the co-expression network analysis, the correlation between the LSM7-7A gene and related genes was illustrated through Gene Ontology (GO) enrichment analysis. Furthermore, the LSM7-7A gene was related to the Arabidopsis homologous salt tolerance gene RCY1. This investigation systematically identified the complete candidates of SSM/SLSM genes and their characters in wheat and its progenitors, and provided clues to a better understanding of their contribution during the wheat polyploidy process. Full article
Show Figures

Figure 1

Article
Changes in the Microbial Community in Soybean Plots Treated with Biochar and Poultry Litter
Agronomy 2021, 11(7), 1428; https://doi.org/10.3390/agronomy11071428 - 17 Jul 2021
Cited by 1 | Viewed by 1109
Abstract
The application of organic materials that promote beneficial microbial activity is vital to maintaining soil health and crop productivity. We investigated the effect on the soil microbiome of applying biochar (BC), poultry litter (PL), and a combination of biochar and poultry litter (BC/PL) [...] Read more.
The application of organic materials that promote beneficial microbial activity is vital to maintaining soil health and crop productivity. We investigated the effect on the soil microbiome of applying biochar (BC), poultry litter (PL), and a combination of biochar and poultry litter (BC/PL) in soybean cultivation at the Red River Research Station (Bossier City, LA, USA). We characterized the microbial profiles, community structure, and co-occurrence network from sequencing data to infer microbial interactions in the soil samples collected in the first and second years of each soil treatment (2016 and 2017, respectively). Our results showed that soil treatments with BC, PL, and a combination of both moderately changed the microbial community composition and structure. In particular, genera significantly affected by the different soil treatments were identified via differential abundance analysis. In addition, canonical correspondence analysis revealed that soil chemical properties, total N in the first year, and total C and pH in the second year influenced the community variability. The differentially enriched bacterial ASVs and co-occurring taxa were linked to nutrient cycling. This study provides insights into the impact of soil carbon amendment on the soil microbiome, a process which favors beneficial bacteria and promotes soybean growth. Full article
(This article belongs to the Section Soil and Plant Nutrition)
Show Figures

Figure 1

Article
Influence of Organic and Inorganic Fertilizers on Coriander (Coriandrum sativum L.) Agronomic Traits, Essential Oil and Components under Semi-Arid Climate
Agronomy 2021, 11(7), 1427; https://doi.org/10.3390/agronomy11071427 - 17 Jul 2021
Cited by 2 | Viewed by 741
Abstract
Environmental contamination and the excessive use of inorganic fertilizers resulting in stagnant yields of field crops which necessitate the utilization of combined fertilization approach under changing climatic conditions. Current study was aimed to clarify the influence of several fertilizer sources (chemical, organic, organomineral [...] Read more.
Environmental contamination and the excessive use of inorganic fertilizers resulting in stagnant yields of field crops which necessitate the utilization of combined fertilization approach under changing climatic conditions. Current study was aimed to clarify the influence of several fertilizer sources (chemical, organic, organomineral fertilizers) on yield and quality of coriander (Coriandrum sativum L.). The results revealed that the fertilizer sources significantly affected the yield of coriander cultivars. The absence of “Year × Variety × Fertilizer Type” interactions for any of the noted parameters signaled that the detected “Variety × Fertilizer Type” interactions were constant regardless of the year factor. The recorded values of traits according to fertilizer sources different for the plant height from 61.85 to 69.67 cm, number of branches from 5.98 to 7.71 (piece/plant), number of umbels per the main umbel from 5.62 to 7.18 pieces, seed yield from 1.06 to 1.66 t/ha−1, the biological yield from 4.29 to 5.70 t ha−1, harvest index from 25.29 to 29.41%, essential oil ratio from 0.29 to 0.33%, and essential oil yield from 3.1 to 5.6 L ha−1. Erbaa variety was observed to be superior over the rest of the varieties producing the maximum values of 6.5 L ha−1 of essential oil, 0.36% essential oil content, 30.9% harvest index, 1.81 t/ha seed yield, and 5.9 t ha−1 biological yield with the treatment of chemical fertilizers. Full article
Article
Land Degradation Vulnerability Mapping in a Newly-Reclaimed Desert Oasis in a Hyper-Arid Agro-Ecosystem Using AHP and Geospatial Techniques
Agronomy 2021, 11(7), 1426; https://doi.org/10.3390/agronomy11071426 - 17 Jul 2021
Cited by 8 | Viewed by 1236
Abstract
Modelling land degradation vulnerability (LDV) in the newly-reclaimed desert oases is a key factor for sustainable agricultural production. In the present work, a trial for using remote sensing data, GIS tools, and Analytic Hierarchy Process (AHP) was conducted for modeling and evaluating LDV. [...] Read more.
Modelling land degradation vulnerability (LDV) in the newly-reclaimed desert oases is a key factor for sustainable agricultural production. In the present work, a trial for using remote sensing data, GIS tools, and Analytic Hierarchy Process (AHP) was conducted for modeling and evaluating LDV. The model was then applied within 144,566 ha in Farafra, an inland hyper-arid Western Desert Oases in Egypt. Data collected from climate conditions, geological maps, remote sensing imageries, field observations, and laboratory analyses were conducted and subjected to AHP to develop six indices. They included geology index (GI), topographic quality index (TQI), physical soil quality index (PSQI), chemical soil quality index (CSQI), wind erosion quality index (WEQI), and vegetation quality index (VQI). Weights derived from the AHP showed that the effective drivers of LDV in the studied area were as follows: CSQI (0.30) > PSQI (0.29) > VQI (0.17) > TQI (0.12) > GI (0.07) > WEQI (0.05). The LDV map indicated that nearly 85% of the total area was prone to moderate degradation risks, 11% was prone to high risks, while less than 1% was prone to low risks. The consistency ratio (CR) for all studied parameters and indices were less than 0.1, demonstrating the high accuracy of the AHP. The results of the cross-validation demonstrated that the performance of ordinary kriging models (spherical, exponential, and Gaussian) was suitable and reliable for predicting and mapping soil properties. Integrated use of remote sensing data, GIS, and AHP would provide an effective methodology for predicting LDV in desert oases, by which proper management strategies could be adopted to achieve sustainable food security. Full article
(This article belongs to the Section Precision and Digital Agriculture)
Show Figures

Figure 1

Article
The GASA Gene Family in Cacao (Theobroma cacao, Malvaceae): Genome Wide Identification and Expression Analysis
Agronomy 2021, 11(7), 1425; https://doi.org/10.3390/agronomy11071425 - 16 Jul 2021
Cited by 20 | Viewed by 1497
Abstract
The gibberellic acid-stimulated Arabidopsis (GASA/GAST) gene family is widely distributed in plants and involved in various physiological and biological processes. These genes also provide resistance to abiotic and biotic stresses, including antimicrobial, antiviral, and antifungal. We are interested in characterizing the [...] Read more.
The gibberellic acid-stimulated Arabidopsis (GASA/GAST) gene family is widely distributed in plants and involved in various physiological and biological processes. These genes also provide resistance to abiotic and biotic stresses, including antimicrobial, antiviral, and antifungal. We are interested in characterizing the GASA gene family and determining its role in various physiological and biological process in Theobroma cacao. Here, we report 17 tcGASA genes distributed on six chromosomes in T. cacao. The gene structure, promoter region, protein structure and biochemical properties, expression, and phylogenetics of all tcGASAs were analyzed. Phylogenetic analyses divided tcGASA proteins into five groups. Among 17 tcGASA genes, nine segmentally duplicating genes were identified which formed four pairs and cluster together in phylogenetic tree. Differential expression analyses revealed that most of the tcGASA genes showed elevated expression in the seeds (cacao food), implying their role in seed development. The differential expression of tcGASAs was recorded between the tolerant and susceptible cultivars of cacao, which indicating their possible role as fungal resistant. Our findings provide new insight into the function, evolution, and regulatory system of the GASA family genes in T.cacao and may suggest new target genes for development of fungi-resistant cacao varieties in breeding programs. Full article
(This article belongs to the Special Issue Omics Approaches for Crop Improvement)
Show Figures

Figure 1

Article
Performance and Stability of Different Monoecious Hemp Cultivars in a Multi-Environments Trial in North-Eastern Italy
Agronomy 2021, 11(7), 1424; https://doi.org/10.3390/agronomy11071424 - 16 Jul 2021
Cited by 2 | Viewed by 876
Abstract
The seed yield in hemp (Cannabis sativa L.) is strongly influenced, besides by genotype, by environment and the genotype x environment interaction, so establishing the fitness and stability of hemp cultivars in multiple environments is necessary. The purpose of this study was [...] Read more.
The seed yield in hemp (Cannabis sativa L.) is strongly influenced, besides by genotype, by environment and the genotype x environment interaction, so establishing the fitness and stability of hemp cultivars in multiple environments is necessary. The purpose of this study was to investigate the performance and degree of stability and variance of seed yield, the main related traits, and the correlation among the traits in five hemp monoecious cultivars cultivated in six different environments. The environments resulted from the combination of four locations, two years, and two delayed sowings in a Mediterranean area of north-eastern Italy, and the stability index of the weighted average of absolute scores (WAAS) was used in order to identify the most productive and stable genotypes on the basis of their deviation from the average performance across environments. In this studied area, early varieties, such as Fedora and Felina, proved to be the best performing and stable for seed yield and both increased their yield in correspondence to delayed sowing times, opening up the possibility of cultivating hemp as a second crop. Among the climate parameters, high temperatures during the early grain filling period led to a progressive decrease in seed yield. For a dual-purpose crop, a good compromise could be a late monoecious cultivar (like Futura, in the present experiment), which, if sown early, could certainly provide notable biomass production and acceptable seed yield. Full article
(This article belongs to the Section Crop Breeding and Genetics)
Show Figures

Figure 1

Article
Impact of Long-Term Manure and Sewage Sludge Application to Soil as Organic Fertilizer on the Incidence of Pathogenic Microorganisms and Antibiotic Resistance Genes
Agronomy 2021, 11(7), 1423; https://doi.org/10.3390/agronomy11071423 - 16 Jul 2021
Cited by 1 | Viewed by 987
Abstract
The reuse of stabilized (under thermophilic conditions) sewage sludge and manure on agricultural soils is a common practice. The aim of this study was to evaluate the risks associated with their repeated applications on the spread of pathogenic bacteria and antibiotic resistance genes [...] Read more.
The reuse of stabilized (under thermophilic conditions) sewage sludge and manure on agricultural soils is a common practice. The aim of this study was to evaluate the risks associated with their repeated applications on the spread of pathogenic bacteria and antibiotic resistance genes (ARGs) that encode resistance to tetracycline (tetA and tetW), sulphonamide (sul1 and sul2), erythromycin (ermB), vancomycin (vanA) and integron genetic element (intI1). The trial fields has been regularly fertilized every 3rd year since 1996 with manure (MF; 330 kg N/ha) and sewage sludge (SF; 330 kg N/ha and SF3; 990 kg N/ha). Unfertilized soil (CF) served as a control. Samples were collected at different time points: (i) right before fertilization (which was also 3 years after the last fertilization), (ii) 5 months after fertilization, and (iii) 11 months after fertilization. The relative abundance of amplicon sequence variants (ASVs) assigned to potentially pathogenic bacteria was low (0.3% and 0.25% in sludge and manure, respectively), and no association with the application of these fertilizers was found. On the other hand, our data indicate that an increased relative abundance of the ARGs sul1 and tetW was significantly associated with these fertilizer applications, and sul1 was increased in all treatments regardless of the time. It is suggested that sul1 should be monitored in organically fertilized soils to prevent its spread and possible further accumulation in crops. Full article
Show Figures

Figure 1

Article
How Do Different Cocoa Genotypes Deal with Increased Radiation? An Analysis of Water Relation, Diffusive and Biochemical Components at the Leaf Level
Agronomy 2021, 11(7), 1422; https://doi.org/10.3390/agronomy11071422 - 16 Jul 2021
Cited by 2 | Viewed by 1045
Abstract
The cultivation of cocoa (Theobroma cacao L.) is traditionally managed under shade because of its photosynthetic characteristics; however, its behavior can vary according to the genotype and environmental conditions where it is grown. In this sense, here, we explore the possible mechanisms [...] Read more.
The cultivation of cocoa (Theobroma cacao L.) is traditionally managed under shade because of its photosynthetic characteristics; however, its behavior can vary according to the genotype and environmental conditions where it is grown. In this sense, here, we explore the possible mechanisms of protection against radiation stress and how these mechanisms are affected by variation between cocoa genotypes. Therefore, we evaluate the effect of the radiation level (HPAR, 2100 ± 46 mol m−2 s−1; MPAR, 1150 ± 42 mol m−2 s−1; LPAR, 636 ± 40 mol m−2 s−1) on the water status and gas exchange in plants of different cocoa genotypes (CCN-51, ICS-1, ICS-95, LUKER-40 and LUKER-50), and the occurrence of photoinhibition of PSII (as a marker of photodamage), followed by a characterization of the protection mechanisms, including the dynamics of photosynthetic pigments and enzymatic and non-enzymatic antioxidant systems. We found significant changes in the specific leaf area (SLA) and the water potential of the leaf (ΨL) due to the level of radiation, affecting the maximum quantum yield of PSII (Fv/Fm), which generated dynamic photoinhibition processes (PIDyn). Cocoa genotypes showed the lowest Light-saturated maximum net carbon assimilation rate (Amax) in HPAR. Moreover, the maximum carboxylation rate (Vcmax) was negatively affected in HPAR for most cocoa genotypes, indicating less RuBisCO activity except for the ICS-95 genotype. The ICS-95 showed the highest values of Vcmax and maximum rate of regeneration of ribulose-1,5-bisphosphate (RuBP) controlled by electron transport (Jmax) under HPAR. Hence, our results show that some genotypes were acclimated to full sun conditions, which translated into greater carbon use efficiency due to the maximization of photosynthetic rates accompanied by energy dissipation mechanisms. Full article
(This article belongs to the Special Issue Advances in Understanding Physiological Processes of the Cacao Tree)
Show Figures

Figure 1

Article
Controlled Grazing of Maize Residues Increased Carbon Sequestration in No-Tillage System: A Case of a Smallholder Farm in South Africa
Agronomy 2021, 11(7), 1421; https://doi.org/10.3390/agronomy11071421 - 15 Jul 2021
Cited by 1 | Viewed by 778
Abstract
Despite the positive impact of no-tillage (NT) on soil organic carbon (SOC), its potential to reduce soil CO2 emission still needs enhancing for climate change mitigation. Combining NT with controlled-grazing of crop residues is known to increase nutrient cycling; however, the impacts [...] Read more.
Despite the positive impact of no-tillage (NT) on soil organic carbon (SOC), its potential to reduce soil CO2 emission still needs enhancing for climate change mitigation. Combining NT with controlled-grazing of crop residues is known to increase nutrient cycling; however, the impacts on soil CO2 effluxes require further exploration. This study compared soil CO2 effluxes and SOC stocks from conventional tillage with free grazing (CTFG), NT with free grazing (NTFG), NT without grazing (NTNG), NT without crop residues (NTNR) and NT with controlled-grazing (NTCG), in South Africa. Soil CO2 effluxes were measured 1512 times over two years using LI-COR 6400XT, once to thrice a month. Baseline SOCs data were compared against values obtained at the end of the trial. Overall, NTCG decreased soil CO2 fluxes by 55 and 29% compared to CTFG and NTNR, respectively. NTCG increased SOCs by 3.5-fold compared to NTFG, the other treatments resulted in SOC depletion. The increase in SOCs under NTCG was attributed to high C input and also low soil temperature, which reduce the SOC mineralization rate. Combining NT with postharvest controlled-grazing showed high potential to increase SOCs, which would help to mitigate climate change. However, it was associated with topsoil compaction. Therefore, long-term assessment under different environmental, crop, and soil conditions is still required. Full article
(This article belongs to the Section Farming Sustainability)
Show Figures

Figure 1

Review
The Potential of Small Grains Crops in Enhancing Biofortification Breeding Strategies for Human Health Benefit
Agronomy 2021, 11(7), 1420; https://doi.org/10.3390/agronomy11071420 - 15 Jul 2021
Cited by 2 | Viewed by 800
Abstract
Nutrition is a source of energy, and building material for the human organism. The quality of food has an effect on the quality of individual life. Minerals and vitamins participate in various catalytic and regulatory functions of the main metabolic processes: absorption, transport, [...] Read more.
Nutrition is a source of energy, and building material for the human organism. The quality of food has an effect on the quality of individual life. Minerals and vitamins participate in various catalytic and regulatory functions of the main metabolic processes: absorption, transport, redox and biosynthesis of organic compounds, genetic information transfer, etc. Regular consumption of dietary fibers like β-glucans and oat-specific phenolics, antioxidants, and avenanthramides, stimulate innate and acquired immunity, prevent cancer, obesity, reduce glucose, total cholesterol and triglyceride blood levels and regulate the expression of cholesterol-related genes. Thus, all those compounds are vitally important for the normal functional status of the human body. A deficiency in one or another essential nutrient causes disruptions in human metabolism, thus leading to serious illnesses. Plants are the main source of essential nutrients that are bioavailable for humans. One of the most popular groups of staple crops are the small grains crops (SGC), so these crops are most often used for biofortification purposes. Exploiting the potential of plant resources, biofortification is a long-term strategy, aimed at increasing the number of essential micro- and macronutrients in major food sources and ensuring their bioavailability. The most productive way to implement such strategy is the active use of the possibilities offered by collections of plant genetic resources, including SGC, concentrated in various countries of the world. The collections of plant resources contain both cultivated plants and their wild relatives that possess the required composition of micro- and macronutrients. A complex scientific approach to studying plant germplasm collections, together with agricultural practices (soil enrichment with fertilizers with a required composition), genetic biofortification (traditional breeding, marker-assisted selection or genetic engineering tactics), and their combinations will lead to the development of new biofortified cultivars and improvement of old ones, which can be used to solve the problems of unbalanced nutrition (malnutrition or hidden hunger) in different regions of the world. Full article
(This article belongs to the Special Issue Cereal Biofortification: Strategies, Challenges and Benefits)
Article
Monitoring of Emerging Water Stress Situations by Thermal and Vegetation Indices in Different Almond Cultivars
Agronomy 2021, 11(7), 1419; https://doi.org/10.3390/agronomy11071419 - 15 Jul 2021
Viewed by 1151
Abstract
In recent years, the area dedicated to modern irrigated almond plantations has increased significantly in Spain. However, the legal irrigation allocations are lower than the maximum water requirements of the crop in most cases. Therefore, almond growers are forced to implement regulated deficit [...] Read more.
In recent years, the area dedicated to modern irrigated almond plantations has increased significantly in Spain. However, the legal irrigation allocations are lower than the maximum water requirements of the crop in most cases. Therefore, almond growers are forced to implement regulated deficit irrigation strategies on their farms, applying water stress in certain resistant phenological periods and avoiding it in sensitive periods. Given the need to monitor the water status of the crop, especially in the most sensitive periods to water stress, the objective of this work was to evaluate the sensitivity of two UAV-based crop water status indicators to detect early water stress conditions in four almond cultivars. The field trial was conducted during 2020 in an experimental almond orchard, where two irrigation strategies were established: full irrigation (FI), which received 100% of irrigation requirements (IR), and regulated deficit irrigation (RDI), which received 70% of IR during the whole irrigation period except during the kernel-filling stage when received 40% IR. The UAV flights were performed on four selected dates of the irrigation season. The Crop Water Status Index (CWSI) and the Normalized Difference Vegetation Index (NDVI) were derived from thermal and multispectral images, respectively, and compared to classical water status indicators, i.e., stem water potential (Ψstem), stomatal conductance (gs), and photosynthetic rate (AN). Of the four flights performed, three corresponded to mild water stress conditions and a single flight was performed under moderate water stress conditions. Under mild water stress, CWSI was not able to capture the differences between FI and RDI trees that were observed with Ψstem. Under moderate stress conditions, CWSI was sensitive to the water deficit reached in the trees and showed significant differences among both irrigation treatments. No differences were observed in the CWSI and NVDI response to water stress among cultivars. Although NDVI and CWSI were sensitive to water stress, the low signal intensity observed in NDVI makes this index less robust than CWSI to monitor crop water stress. It can be concluded that UAV-based CWSI measurements are reliable to monitor almond water status, although for early (mild) levels of water stress, Ψstem seems to be the preferred option. Full article
Show Figures

Figure 1

Article
Organic Oat Response to Variety, Seeding Rate, and Nutrient Source and Rate
Agronomy 2021, 11(7), 1418; https://doi.org/10.3390/agronomy11071418 - 15 Jul 2021
Cited by 1 | Viewed by 821
Abstract
Oat (Avena sativa L.) is an important crop for organic production systems in the upper Midwest, but limited information on optimal nutrient management and seeding rates is available. Oat varieties representing three maturity groups were evaluated during 2015 and 2016 in Lamberton, [...] Read more.
Oat (Avena sativa L.) is an important crop for organic production systems in the upper Midwest, but limited information on optimal nutrient management and seeding rates is available. Oat varieties representing three maturity groups were evaluated during 2015 and 2016 in Lamberton, Minnesota on organically certified ground previously planted to alfalfa (Medicago sativa L.). Two oat seeding rates (110 and 145 kg ha−1), two nutrient sources (raw and composted beef manure), and four N application rates (0, 50, 100, and 150 kg ha−1) were studied. Plant population; number of tillers; grain yield; grain nutrient removal (primary and secondary macronutrients); and post-harvest soil nitrate, Bray P-1, and K in the top 0 to 15 cm layer were measured. Grain yield was 4.8, 4.0, and 3.8 kg ha−1 for late maturing Deon, early maturing Tack/Saber, and medium maturing Shelby, respectively. Yield was optimized at a nutrient application rate of 82.3 kg N ha−1 and decreased at higher rates. Grain N content was not related to yield, suggesting that the other nutrients in manure and compost may have been responsible for optimizing yield. High application rates resulted in increased residual soil test P and K levels, which could become problematic if not managed appropriately. Full article
(This article belongs to the Section Soil and Plant Nutrition)
Show Figures

Figure 1

Article
Unraveling Factors Affecting Micropropagation of Four Persian Walnut Varieties
Agronomy 2021, 11(7), 1417; https://doi.org/10.3390/agronomy11071417 - 15 Jul 2021
Cited by 4 | Viewed by 947
Abstract
Walnuts are considered recalcitrant to tissue culture, with a great genetic determinism on all stages of micropropagation; while other factors, also with great impact, become more complicated with the reproduction of newly realized varieties. In this research, a holistic approach aimed to determine [...] Read more.
Walnuts are considered recalcitrant to tissue culture, with a great genetic determinism on all stages of micropropagation; while other factors, also with great impact, become more complicated with the reproduction of newly realized varieties. In this research, a holistic approach aimed to determine the influence of genotype and the nutritive formulation throughout the whole cycle of micropropagation of four Persian walnut varieties (Juglans regia L.) was presented. During the in vitro establishment it was determined that besides genotype and culture medium, the effect of collection season and the likely interaction amongst factors had a great influence on the successful introduction of all four genotypes. However, all cultures were affected by a deep decay, being necessary the introduction of ethylenediamine di-2-hydroxyphenyl acetate ferric, as iron source, and Phloroglucinol in both Murashige and Skoog (1962) and the corrected Driver and Kuniyuki (1987) formulations. These modifications allowed the stabilization of cultures, maintaining thereafter a steady quality. Either proliferation, rooting and ex vitro survival of four clones were affected by the culture medium, obtaining the best results with the corrected Driver and Kuniyuki (1987) formulation. Finally, in vitro plants produced from all clones were acclimated with high survival rates (75.9–91.1% for the best culture medium), depending of clone and the culture medium used. Microsatellite analysis showed that micropropagated plants maintained the same genetic profiles of their corresponding donor trees. These results might contribute to deepening of the understanding of factors that determine the success of micropropagation of walnuts, and the extents of its influence; whereas, it sets the basis for the commercial micropropagation of all four clones. Full article
(This article belongs to the Special Issue Role of Plant Tissue Culture in Agricultural Research and Production)
Show Figures

Figure 1

Previous Issue
Next Issue
Back to TopTop