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Agronomy, Volume 11, Issue 1 (January 2021) – 190 articles

Cover Story (view full-size image): Fire blight caused by the bacterial pathogen Erwinia amylovora is a devastating disease of apple (Malus). In 2020, a naturally occurring fire blight outbreak caused by a streptomycin-resistant strain of E. amylovora occurred in the United States Department of Agriculture (USDA) National Plant Germplasm System Malus collection, presenting a rare opportunity to assess fire blight susceptibility in diverse Malus species. Phenotypic evaluation of fire blight severity was conducted for 1142 trees in June, representing 41 species, and again in July, with a 667-tree subset of 34 species. After fire blight infections were removed by pruning, 2525 trees representing 48 species were rated on a scale of 0–6 for cut severity. Trees with cut severity ratings of ≤3 may be mildly resistant to fire blight, while trees with severity ratings of ≥4 were highly susceptible. View this paper
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Open AccessArticle
Reduced Pollination Efficiency Compromises Some Physicochemical Qualities in Gac (Momordica cochinchinensis Spreng.) Fruit
Agronomy 2021, 11(1), 190; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010190 - 19 Jan 2021
Viewed by 435
Abstract
Gac is valued for the nutritious aril surrounding its seed. When pollinators are limited or when flower sex expression is female-biased, hand pollination is necessary. Here, female flowers were hand pollinated with male flowers or pollen stored for up to 84 days at [...] Read more.
Gac is valued for the nutritious aril surrounding its seed. When pollinators are limited or when flower sex expression is female-biased, hand pollination is necessary. Here, female flowers were hand pollinated with male flowers or pollen stored for up to 84 days at 4 or −20 °C, and fruit set and some qualities of mature fruit were evaluated. Cool storage reduced pollen viability (germinability and pollen tube length) and compromised fruit set (10–87%) compared with fresh pollen (97%). Fruit weight was also reduced at least by 8%, and oil concentration in aril by 40%. However, the lycopene and β-carotene concentrations in aril were largely uncompromised, and some fruits were of a marketable weight (>1.2 kg) and quality. Cool storage is a low-cost method for the short-term storage of Gac pollen. However, methods for drying pollen to an inactive state need investigation for a storage protocol, and for improvements in fruit set and fruit physicochemical qualities using hand pollination. Full article
(This article belongs to the Special Issue Optimising Practices for Crops in Protected Cultivation)
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Open AccessArticle
The Effect of Foliar Fertilization on the Resistance of Pea (Pisum sativum L.) Seeds to Mechanical Damage
Agronomy 2021, 11(1), 189; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010189 - 19 Jan 2021
Viewed by 393
Abstract
The aim of the study was to investigate the effect of foliar fertilization on the morphological and mechanical properties of pea seeds (Pisum sativum L.) and to determine the dependences between the morphological features and chemical composition of pea seeds and their [...] Read more.
The aim of the study was to investigate the effect of foliar fertilization on the morphological and mechanical properties of pea seeds (Pisum sativum L.) and to determine the dependences between the morphological features and chemical composition of pea seeds and their susceptibility to mechanical damage. Field experimentation was carried out in 2015–2017 (south-eastern Poland, 49°59′ N, 21°57′ E). Micronutrient conventional fertilization (N1) and organic fertilizer (N2) were tested on eight pea cultivars. The mechanical parameters assessed included compression force (FD), relative deformation (DR), and energy (ED). Application of foliar fertilizer increased the strength of seeds and their ability to resist mechanical damage under quasi-static loads. The seeds of plants fertilized with N1 were more resistant to mechanical damage than the seeds of plants fertilized with N2. Seeds with larger dimensions, mass, density, and a more spherical shape were damaged under the action of less force and energy, and they deformed less. Seeds with higher protein, fat, ash, and K content and lower NFE, Fe, Zn, and Cu content were more resistant to mechanical damage. The mathematical models created provide knowledge about the impact of foliar fertilizer on the mechanical properties of seeds. Full article
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Open AccessArticle
Early-Stage Phenotyping of Root Traits Provides Insights into the Drought Tolerance Level of Soybean Cultivars
Agronomy 2021, 11(1), 188; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010188 - 19 Jan 2021
Viewed by 496
Abstract
Soybean (Glycine max (L.) Merr.) may contribute to the agro-ecological transition of cropping systems in Europe, but its productivity is severely affected by summer drought. New drought-avoidance cropping strategies, such as early sowing, require cultivars with high early plant growth under suboptimal [...] Read more.
Soybean (Glycine max (L.) Merr.) may contribute to the agro-ecological transition of cropping systems in Europe, but its productivity is severely affected by summer drought. New drought-avoidance cropping strategies, such as early sowing, require cultivars with high early plant growth under suboptimal conditions. This study aims at phenotyping early-stage root and shoot traits of 10 cultivars commonly grown in Europe. Cultivars were grown in minirhizotrons under two soil moisture status in controlled conditions. Root and shoot traits were evaluated at 10 days after sowing. Field early growth of two cultivars was also analyzed under early and conventional sowing dates. A significant intraspecific variability (p < 0.05) was found for most investigated shoot and root morpho-physiological traits regardless of the soil moisture status under controlled conditions. However, no significant difference among cultivars (p > 0.05) was found in terms of root architectural traits that were mainly affected by water stress. Total root length was positively correlated with shoot length and shoot dry matter (p < 0.05). Under field conditions, the differences between cultivars were expressed by the canopy cover at emergence, which determines the subsequent canopy cover dynamics. The significant early growth difference among cultivars was not related to the maturity group. Cultivars characterized by high root depth and length, high root density and narrow root angle could be considered as good candidates to cope with water stress via better soil exploration. New agronomic strategies mobilizing the diversity of cultivars could thus be tested to improve soybean water use efficiency in response to climate change. Full article
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Open AccessArticle
Topography Controls N2O Emissions Differently during Early and Late Corn Growing Season
Agronomy 2021, 11(1), 187; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010187 - 19 Jan 2021
Viewed by 316
Abstract
Topography affects soil hydrological, pedological, and biochemical processes and may influence nitrous oxide (N2O) emissions into the atmosphere. While N2O emissions from agricultural fields are mainly measured at plot scale and on flat topography, intrafield topographical and crop growth [...] Read more.
Topography affects soil hydrological, pedological, and biochemical processes and may influence nitrous oxide (N2O) emissions into the atmosphere. While N2O emissions from agricultural fields are mainly measured at plot scale and on flat topography, intrafield topographical and crop growth variability alter soil processes and might impact N2O emissions. The objective of this study was to examine the impact of topographical variations on crop growth period dependent soil N2O emissions at the field scale. A field experiment was conducted at two agricultural farms (Baggs farm; BF and Research North; RN) with undulating topography. Dominant slope positions (upper, middle, lower and toeslope) were identified based on elevation difference. Soil and gas samples were collected from four replicated locations within each slope position over the whole corn growing season (May–October 2019) to measure soil physio-chemical properties and N2O emissions. The N2O emissions at BF ranged from −0.27 ± 0.42 to 255 ± 105 g ha−1 d−1. Higher cumulative emissions were observed from the upper slope (1040 ± 487 g ha−1) during early growing season and from the toeslope (371 ± 157 g ha−1) during the late growing season with limited variations during the mid growing season. Similarly, at RN farm, (emissions ranged from −0.50 ± 0.83 to 70 ± 15 g ha−1 d−1), the upper slope had higher cumulative emissions during early (576 ± 132 g ha−1) and mid (271 ± 51 g ha−1) growing season, whereas no impact of slope positions was observed during late growing season. Topography controlled soil and environmental properties differently at different crop growth periods; thus, intrafield variability must be considered in estimating N2O emissions and emission factor calculation from agricultural fields. However, due to large spatial variations in N2O emissions, further explorations into site-specific analysis of individual soil properties and their impact on N2O emissions using multiyear data might help to understand and identify hotspots of N2O emissions. Full article
(This article belongs to the Section Farming Sustainability)
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Open AccessArticle
Effects of Fertigation with Untreated and Treated Leachates from Municipal Solid Waste on the Microelement Status and Biometric Parameters of Viola × wittrockiana
Agronomy 2021, 11(1), 186; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010186 - 19 Jan 2021
Viewed by 387
Abstract
Landfill leachate can release pollutants into the environment. Nevertheless, it can be treated using a phytodepuration system via constructed wetlands to reduce contaminants. Moreover, this leachate can also increase the availability of macro and micronutrients in soil and water. In this trial, the [...] Read more.
Landfill leachate can release pollutants into the environment. Nevertheless, it can be treated using a phytodepuration system via constructed wetlands to reduce contaminants. Moreover, this leachate can also increase the availability of macro and micronutrients in soil and water. In this trial, the reuse of untreated and treated wastewater from municipal solid waste (MSW) for fertigation was assessed. Plantlets of Viola × wittrockiana (pansy) were grown in a greenhouse and five fertigation treatments were applied: W9.0 (pure wastewater, EC 9.0 dS m−1), W4.5 (diluted wastewater, EC 4.5 dS m−1), DW4.5 (depurated wastewater, EC 4.5 dS m−1), PW4.5 (phytodepurated wastewater, EC 4.5 dS m−1), and T (tap water, control, EC 1.5 dS m−1). The treatment with untreated wastewater had a negative effect on plant dry weight, leaf size, specific leaf area, water content, and the number of closed and open flowers, due to the high concentration of SO42− in the fertigation water. It also reduced the content of Cu, Mn, Fe, and Zn with respect to the control, because of the dry biomass diminution. Conversely, fertigation with phytodepurated wastewater enhanced root and shoot dry weight, water content, and the number of closed and open flowers. Cu and Mn contents in flowers surpassed the content detected in plants fertigated with untreated leachates. These findings demonstrate that phytodepurated wastewater obtained from MSW can be employed for the fertigation of this species. Full article
(This article belongs to the Special Issue Management of Crops Fertigation)
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Open AccessArticle
Reaction of Camelina (Camelina sativa (L.) Crantz) to Different Foliar Fertilization
Agronomy 2021, 11(1), 185; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010185 - 19 Jan 2021
Viewed by 331
Abstract
Camelina (Camelina sativa (L.) Crantz) is an oil plant that can increase farmland biodiversity in many parts of the world. In addition to food importance, it is a good alternative in biofuel production. The aim of the experiment was to evaluate the [...] Read more.
Camelina (Camelina sativa (L.) Crantz) is an oil plant that can increase farmland biodiversity in many parts of the world. In addition to food importance, it is a good alternative in biofuel production. The aim of the experiment was to evaluate the response of camelina, the variety Śmiłowska (spring form), to various foliar fertilization. The combined application of three fertilizers had the most positive effect on the tested features and economic result: urea (46% N), magnesium sulfate (16% MgO + 32% SO3), and Plonvit R (multi-component fertilizer). The obtained increase in seed yield after the application of the above variant was 0.54 t ha−1, i.e., 37.5% compared to the control. The remaining fertilization combinations did not have a significant effect on seed yield, which amounted on average to 1.66 t ha−1. The yield of fat and protein amounted to 0.68 t·ha−1 and 0.42 t ha−1, respectively, and was strongly correlated with seed yield. The yielding of the variety Śmiłowska was stable over the years of the study. The combined use of three foliar fertilizers (variant H) increased the SPAD (soil plant analysis development) and LAI (leaf area index) values compared to the control. The application of urea alone reduced crude fat content in the seeds. Full article
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Open AccessArticle
Initial Crown Diameter Influences on the Fruit Yield and Quality of Strawberry Pircinque
Agronomy 2021, 11(1), 184; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010184 - 19 Jan 2021
Viewed by 360
Abstract
In strawberry production, the combination of a high productive performance and fruits with desirable physicochemical characteristics requires the use of plants with a good quality and high initial vigor. This study aimed to evaluate the effect of plants with different crown diameters on [...] Read more.
In strawberry production, the combination of a high productive performance and fruits with desirable physicochemical characteristics requires the use of plants with a good quality and high initial vigor. This study aimed to evaluate the effect of plants with different crown diameters on the productive performance and fruit quality of strawberry plants of the cultivar ‘Pircinque’ (Short Day). The study was conducted in two evaluation cycles (2016/2017 and 2017/2018). The experimental design was divided into randomized blocks, with four repetitions, and plots consisting of 20 plants. This study evaluated the crown diameters of plants of 5, 7, 9, 11, 13, 15, 17, and 19 mm. The productivity and number of fruit values increased significantly by 57% with larger caliber plants, which also provided precocity of productivity. The use of more vigorous plants also favored the production of fruits with higher soluble solids/titratable acidity ratios (+28%) and with epidermis coloration closer to intense red (−4.3%). For the cultivar ‘Pircinque’, plant crown diameters between 15 and 17 mm are the most favorable because they condition the best productive performances in combination with precocity and a good fruit quality. Full article
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Open AccessReview
Sugarcane Distillery Spent Wash (DSW) as a Bio-Nutrient Supplement: A Win-Win Option for Sustainable Crop Production
Agronomy 2021, 11(1), 183; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010183 - 19 Jan 2021
Viewed by 414
Abstract
Industrial pollution has been continuously soaring and causing serious threats to the soil, water, and air quality. The increase in industrialization has not only covered the large areas, but also created a large quantity of wastewater which is difficult to handle. The water [...] Read more.
Industrial pollution has been continuously soaring and causing serious threats to the soil, water, and air quality. The increase in industrialization has not only covered the large areas, but also created a large quantity of wastewater which is difficult to handle. The water produced from different industries is getting its place in the agriculture. However, the challenge is to properly use wastewater, so that the application of wastewater does not cause any soil and environmental problems. The distillery spent wash (DSW) is a liquid waste that is produced from the sugarcane industry. It contains a large load of both organic and inorganic substances. Also, DSW contains a sufficient amount of macronutrients (nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and Sulphur (S)) and micronutrients (zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn)), which in turn improves the growth and yield of crops. The optimized doses of DSW substantially improve soil enzymatic and microbial activities, organic carbon, nutrient uptake, soil porosity, water holding capacity, aggregate stability, and anti-oxidant activities, which in turn improve the photosynthetic efficiency, growth and yield. However, the inadequate knowledge about the DSW characteristics and methods of its agricultural application present questions concerning environmental quality for groundwater pollution. Therefore, to obtain a better understanding about the DWS, here, we discussed the effects of DSW on soil quality, crop yield, and its implications for agriculture and water quality. Full article
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Open AccessArticle
Identification of Associations between SSR Markers and Quantitative Traits of Maize (Zea mays L.)
Agronomy 2021, 11(1), 182; https://doi.org/10.3390/agronomy11010182 - 19 Jan 2021
Viewed by 426
Abstract
Microsatellite or simple sequence repeat (SSR) markers have wide applicability for genetic analysis in crop plant improvement strategies. Marker-assisted selection is an important tool for plant breeders to increase the efficiency of a breeding process, especially for multigenic traits, highly influenced by the [...] Read more.
Microsatellite or simple sequence repeat (SSR) markers have wide applicability for genetic analysis in crop plant improvement strategies. Marker-assisted selection is an important tool for plant breeders to increase the efficiency of a breeding process, especially for multigenic traits, highly influenced by the environment. In this paper, the relationships between SSR markers and 26 quantitative traits of hybrid maize varieties (Zea mays L.) were analyzed. Association analyses were performed based on 30 SSR primers in a set of thirteen hybrid maize varieties. A total of 112 SSR markers were detected in these genotypes. The number of alleles per locus ranged from 1 to 17, with the average number of alleles per locus equal to 3.7. The number of molecular markers associated with observed traits ranged from 1 (for the number of kernels in row, ears weight and fresh weight of one plant) to 14 (for damage of maize caused by P. nubilalis) in 2016 as well as from 1 (for soil plant analysis development—SPAD, the number of grains in ear and fresh weight of one plant) to 12 (for carotenoids content) in 2017. The sum of statistically significant associations between SSR markers and at least one trait was equal to one hundred sixty in 2016 as well as one hundred twenty-five in 2017. Marker trait associations (MTAs) were found on the basis of regression analysis. The proportion of the total phenotypic variances of individual traits explained by the marker ranged from 24.4% to 77.7% in the first year of study and from 24.3% to 77.9% in 2017. Twenty-two SSR markers performed a significant effect on at least one tested trait in both years of experiment. The three markers (phi021/4, phi036/3, and phi061/2) can be a good tool in marker-assisted selection because they allow simultaneous selection for multiple traits in both years of study, such as the number of kernels in row and the number of grains in ear (phi021/4), the number of plant after germination, the number of plants before harvest, and the number of ears (phi036/3), as well as moisture of grain and length of ears (phi061/2). Full article
Open AccessReview
Crop Management with the IoT: An Interdisciplinary Survey
Agronomy 2021, 11(1), 181; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010181 - 18 Jan 2021
Cited by 1 | Viewed by 383
Abstract
In this study, we analyze how crop management will benefit from the Internet of Things (IoT) by providing an overview of its architecture and components from agronomic and technological perspectives. The present analysis highlights that IoT is a mature enabling technology with articulated [...] Read more.
In this study, we analyze how crop management will benefit from the Internet of Things (IoT) by providing an overview of its architecture and components from agronomic and technological perspectives. The present analysis highlights that IoT is a mature enabling technology with articulated hardware and software components. Cheap networked devices can sense crop fields at a finer grain to give timeliness warnings on the presence of stress conditions and diseases to a wider range of farmers. Cloud computing allows reliable storage, access to heterogeneous data, and machine-learning techniques for developing and deploying farm services. From this study, it emerges that the Internet of Things will draw attention to sensor quality and placement protocols, while machine learning should be oriented to produce understandable knowledge, which is also useful to enhance cropping system simulation systems. Full article
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Open AccessArticle
A Compact Weighing Lysimeter to Estimate the Water Infiltration Rate in Agricultural Soils
Agronomy 2021, 11(1), 180; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010180 - 18 Jan 2021
Viewed by 258
Abstract
Infiltration estimation is made by tests such as concentric cylinders, which are prone to errors, such as the lateral movement under the ring. Several possibilities have been developed over the last decades to compensate these errors, which are based on physical, electronic, and [...] Read more.
Infiltration estimation is made by tests such as concentric cylinders, which are prone to errors, such as the lateral movement under the ring. Several possibilities have been developed over the last decades to compensate these errors, which are based on physical, electronic, and mathematical principles. In this research, two approaches are proposed to measure the water infiltration rate in a silty loam soil by means of the mass values of a lysimeter weighing under rainfall conditions and different moisture contents. Based on the fact that with the lysimeter it is possible to determine acting soil flows very precisely, then with the help of mass conservation and assuming a downward vertical movement, 12 rain events were analyzed. In addition, it was possible to monitor the behavior of soil moisture and to establish the content at field capacity from the values of the weighing lysimeter, from which both approach are based. The infiltration rate of these events showed a variable rate at the beginning of the rainfall until reaching a maximum, to descend to a stable or basic rate. This basic infiltration rate was 1.49 ± 0.36 mm/h, and this is because soils with fine textures have reported low infiltration capacity. Four empirical or semi-empirical models of infiltration were calibrated with the values obtained with our approaches, showing a better fit with the Horton’s model. Full article
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Open AccessArticle
Estimation of Sensible and Latent Heat Fluxes Using Surface Renewal Method: Case Study of a Tea Plantation
Agronomy 2021, 11(1), 179; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010179 - 18 Jan 2021
Viewed by 280
Abstract
An experiment of sensible and latent heat flux measurement was conducted in a tea plantation near the Yangtze River within Danyang of Jiangsu Province, China. High-frequency (~10 Hz) air temperature measurement with fine-wire thermocouples (⌀ = 50 μm) was used for the estimation [...] Read more.
An experiment of sensible and latent heat flux measurement was conducted in a tea plantation near the Yangtze River within Danyang of Jiangsu Province, China. High-frequency (~10 Hz) air temperature measurement with fine-wire thermocouples (⌀ = 50 μm) was used for the estimation of sensible heat flux (H), and latent heat flux (LE) was extracted as a residual of the energy balance equation using additional measurements of net radiation (Rn) and soil heat flux (G). Results were compared against the eddy covariance (EC) system under unstable conditions only, and days with high precipitation were excluded from further analysis. Half-hourly datasets of the sensible heat flux estimated using the surface renewal method (SR) (HSR) and measured by the EC system (HEC) were analyzed. Results showed good agreement with R2 = 0.80, root mean square error (RMSE) = 27.87 W m−2, relative error (RE) = 9.02%, and a regression slope of 0.68—this slope was used for the calibration of the uncalibrated HSR estimated by SR. On the other hand, the half-hourly dataset of LESR was regressed against EC, and it showed good agreement with relatively high R2 = 0.93, RMSE = 32.99 W·m−2, and RE = 5.67%. Hence, the SR method may estimate the surface fluxes at a relatively low cost, ultimately improving calculations of evapotranspiration. Thus, the SR method could provide an economical tool for improving crop water management of tea plantations. Full article
(This article belongs to the Special Issue Agricultural Water Conservation: Tools, Strategies, and Practices)
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Open AccessArticle
Root Characteristics and Metal Uptake of Maize (Zea mays L.) under Extreme Soil Contamination
Agronomy 2021, 11(1), 178; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010178 - 18 Jan 2021
Viewed by 326
Abstract
Root characteristics and metal uptake in the maize hybrid Naudi were studied in a pot trial, using soil artificially highly polluted with Zn, Cu, Co, Cd, and Pb. The addition of these metals as sulfates decreased the soil pH and increased electrical conductivity. [...] Read more.
Root characteristics and metal uptake in the maize hybrid Naudi were studied in a pot trial, using soil artificially highly polluted with Zn, Cu, Co, Cd, and Pb. The addition of these metals as sulfates decreased the soil pH and increased electrical conductivity. As a result of increased bioavailability in the soil pore water, significantly higher concentrations of metals, particularly Pb, Cu, and Co, were found in the shoot tissues of maize at the 3–4 leaf stage. While the lowest increase was in Cd (0.89 mg kg−1 vs. 0.33 mg kg−1 for controls), Zn reached a critical threshold of 75 mg kg−1 vs. 2.76 mg kg−1. Fresh and dry weights of shoots and roots, as well as root length, were markedly reduced, whereas root diameter, tip density, and the branching index increased considerably. A significant adaptation strategy by maize in the polluted soil was an increased fraction of coarse root length and a decreased fraction of finer roots. We conclude that maize is very sensitive to multiple metal pollution, suggesting its potential use as a test plant to evaluate contaminated soils. As length was the most affected root characteristic, measurement of this parameter could be a way of screening genotypes for tolerance to metal contamination and possibly salinity. There also is future scope for investigating whether K fertilization might mitigate metal phytotoxicity, in view of the negative correlations between the shoot K concentration and concentrations of the supplied metals. Full article
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Open AccessArticle
Enhancing Drought Tolerance and Striga hermonthica Resistance in Maize Using Newly Derived Inbred Lines from the Wild Maize Relative, Zea diploperennis
Agronomy 2021, 11(1), 177; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010177 - 18 Jan 2021
Viewed by 311
Abstract
Recurrent drought and Striga hermonthica (Del.) Benth parasitism constrains maize production in sub-Saharan Africa (SSA). Transfer of resistance genes from wild relatives can improve resistance to drought and Striga in tropical maize. The objectives of this study were to (i) determine the combining [...] Read more.
Recurrent drought and Striga hermonthica (Del.) Benth parasitism constrains maize production in sub-Saharan Africa (SSA). Transfer of resistance genes from wild relatives can improve resistance to drought and Striga in tropical maize. The objectives of this study were to (i) determine the combining ability of 12 extra-early yellow maize inbreds derived from Zea diploperennis and tropical maize germplasm; (ii) classify the inbreds into heterotic groups using heterotic grouping based on the general combining ability (GCA) of multiple traits (HGCAMT) method; (iii) examine hybrid performance under contrasting environments; and (iv) examine the stability of hybrid combinations involving the inbreds. Sixty-six diallel crosses involving the inbreds plus four checks were evaluated for two years under drought, Striga-infested and rainfed environments in Nigeria. Significant differences (p < 0.05) were observed for the effects of genotype, environment, genotype × environment, GCA and specific combining ability (SCA) on grain yield and other measured traits. Inbred lines such as TZdEEI 7 × TZEEI 63 derived from Z. diploperennis and tropical germplasm exceeded the checks by a range of 28 to 41%. Across environments, the hybrid TZdEEI 1 × TZdEEI 7, which was derived from Z. diploperennis, was the highest-yielding with a grain yield of 4302 kg ha−1. The results revealed the predominance of GCA over SCA effects for most measured traits, suggesting that additive gene action governed the inheritance of Striga resistance and drought tolerance related traits in the inbreds. The 12 inbreds were classified into three heterotic groups, while TZEEI 79 and TZdEEI 7 were identified as inbred testers and TZdEEI 7 × TZEEI 12 as a single-cross tester across environments. Hybrid TZdEEI 9 × TZEEI 79 was the highest-yielding and most stable. Other promising hybrids were TZdEEI 7 × TZEEI 79, TZdEEI 1 × TZdEEI 7 and TZdEEI 12 × TZEEI 95. These hybrids should be extensively tested on-farm for potential commercialization in SSA. Overall, our results highlighted the importance of harnessing beneficial alleles from wild relatives of maize for improvement of resistance to Striga and tolerance to drought in adapted maize germplasm. Full article
(This article belongs to the Special Issue Use of Wild Crop Relatives as Genetic Resources in Crop Breeding)
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Open AccessArticle
Competition for Light Interception in Cotton Populations of Different Densities
Agronomy 2021, 11(1), 176; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010176 - 18 Jan 2021
Viewed by 258
Abstract
Modification of the cotton canopy results in shade avoidance and competition for light, which shows that density and spatial arrangement of cotton have a great impact on light interception. This experiment was conducted in 2018 and 2019 in the experimental field at the [...] Read more.
Modification of the cotton canopy results in shade avoidance and competition for light, which shows that density and spatial arrangement of cotton have a great impact on light interception. This experiment was conducted in 2018 and 2019 in the experimental field at the Institute of Cotton Research of Chinese Academy of Agricultural Science in Anyang city, Henan Province, China. Six plant densities of cotton variety SCRC28 were used to assess spatial competition for light in cotton populations during the whole growing period. Light interception data were collected and analyzed according to the spatial grid method and the extension of Simpson’s 3/8 rule. The results showed that at the bottom of the canopy, greater light interception was observed at high densities than at low densities, while in the external part of the layer of the canopy in the horizontal direction, low light interception was recorded at low densities. Leaf area, aboveground biomass and plant height were obviously correlated with light interception, and the cotton population with a higher density (8.7 plants m−2) performed best at the light interception competition, and with the highest yield. The results will provide guidance on light management through the optimization of the structure of the canopy to provide more solar radiation and a significant basis by which to improve the management of light and canopy architecture. Full article
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Open AccessReview
Review of Horseradish Breeding for Improved Root Quality and Yield in Illinois, USA
Agronomy 2021, 11(1), 175; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010175 - 18 Jan 2021
Viewed by 235
Abstract
Horseradish cultivars are highly heterozygous clones and are maintained through asexual propagation, using root cuttings. For many years, horseradish was believed to be sterile and therefore impossible to improve by traditional sexual crosses. Prior to the 20th century, the only way to improve [...] Read more.
Horseradish cultivars are highly heterozygous clones and are maintained through asexual propagation, using root cuttings. For many years, horseradish was believed to be sterile and therefore impossible to improve by traditional sexual crosses. Prior to the 20th century, the only way to improve horseradish was to select and plant root cuttings from the most desirable plants. Moreover, the development of new improved horseradish cultivars has also been somewhat limited by the lack of viable seed resulting from low fertility of horseradish flowers. However, in Illinois, USA, a horseradish breeding program was initiated in the 1950s to develop additional cultivars to widen the genetic base of the few cultivars being grown at the time. In more recent years, the proven cross breeding technique has been primarily used to obtain new genotypes of horseradish, since it is more efficient in producing new improved cultivars, compared to the polycross method that had been previously used for decades to obtain new genetic combinations. Since horseradish is a minor specialty crop with very little available information regarding breeding procedures, this review was developed to provide a better understanding of pollination barriers and methods for fertility improvement, traditional breeding procedures and cultivar development, and traditional breeding achievements and limitations. The development of new horseradish cultivars is essential for the sustained success of the Illinois, USA industry since it provides growers with a continuous supply of new selections that have increased vigor, outstanding root quality, and high yields. Full article
(This article belongs to the Special Issue Genetic Improvement of Vegetable Crops)
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Open AccessArticle
Identifying Cotton Fields from Remote Sensing Images Using Multiple Deep Learning Networks
Agronomy 2021, 11(1), 174; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010174 - 18 Jan 2021
Viewed by 280
Abstract
Remote sensing imageries processed through empirical and deterministic approaches help predict multiple agronomic traits throughout the growing season. Accurate identification of cotton crop from remotely sensed imageries is a significant task in precision agriculture. This study aims to utilize a deep learning-based framework [...] Read more.
Remote sensing imageries processed through empirical and deterministic approaches help predict multiple agronomic traits throughout the growing season. Accurate identification of cotton crop from remotely sensed imageries is a significant task in precision agriculture. This study aims to utilize a deep learning-based framework for cotton crop field identification with Gaofen-1 (GF-1) high-resolution (16 m) imageries in Wei-Ku region, China. An optimized model for the pixel-wise multidimensional densely connected convolutional neural network (DenseNet) was used. Four widely-used classic convolutional neural networks (CNNs), including ResNet, VGG, SegNet, and DeepLab v3+, were also used for accuracy assessment. The results infer that DenseNet can identify cotton crop features within a relatively shorter time about 5 h for training convergence. The model performance was examined by multiple indicators (P, F1, R, and mIou) produced through the confusion matrix, and the derived cotton fields were then visualized. The DenseNet model has illustrated considerable improvements in comparison with the preceding mainstream models. The results showed that the retrieval precision was 0.948, F1 score was 0.953, and mIou was 0.911. Furthermore, its performance is relatively better in discriminating cotton crop fields’ fine structures when clouds, mountain shadows, and urban built up. Full article
(This article belongs to the Special Issue Applications of Deep Learning in Smart Agriculture)
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Open AccessArticle
Comparison of Drivers of Soil Microbial Communities Developed in Karst Ecosystems with Shallow and Deep Soil Depths
Agronomy 2021, 11(1), 173; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010173 - 18 Jan 2021
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Abstract
Soil erosion is prevalent in karst areas, but few studies have compared the differences in the drivers for soil microbial communities among karst ecosystems with different soil depths, and most studies have focused on the local scale. To fill this research gap, we [...] Read more.
Soil erosion is prevalent in karst areas, but few studies have compared the differences in the drivers for soil microbial communities among karst ecosystems with different soil depths, and most studies have focused on the local scale. To fill this research gap, we investigated the upper 20 cm soil layers of 10 shallow–soil depth (shallow–SDC, total soil depth less than 100 cm) and 11 deep–soil depth communities (deep–SDC, total soil depth more than 100 cm), covering a broad range of vegetation types, soils, and climates. The microbial community characteristics of both the shallow–SDC and deep–SDC soils were tested by phospholipid fatty acid (PLFAs) analysis, and the key drivers of the microbial communities were illustrated by forward selection and variance partitioning analysis. Our findings demonstrated that more abundant soil nutrients supported higher fungal PLFA in shallow–SDC than in deep–SDC (p < 0.05). Furthermore, stronger correlation between the microbial community and the plant–soil system was found in shallow–SDC: the pure plant effect explained the 43.2% of variance in microbial biomass and 57.8% of the variance in the ratio of Gram–positive bacteria to Gram–negative bacteria (G+/G−), and the ratio of fungi to total bacteria (F/B); the pure soil effect accounted for 68.6% variance in the microbial diversity. The ratio of microbial PLFA cyclopropyl to precursors (Cy/Pr) and the ratio of saturated PLFA to monounsaturated PLFA (S/M) as indicators of microbial stress were controlled by pH, but high pH was not conducive to microorganisms in this area. Meanwhile, Cy/Pr in all communities was >0.1, indicating that microorganisms were under environmental stress. Therefore, the further ecological restoration of degraded karst communities is needed to improve their microbial communities. Full article
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Open AccessReview
Conservation and Use of Latin American Maize Diversity: Pillar of Nutrition Security and Cultural Heritage of Humanity
Agronomy 2021, 11(1), 172; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010172 - 18 Jan 2021
Viewed by 1024
Abstract
Latin America is the center of domestication and diversity of maize, the second most cultivated crop worldwide. In this region, maize landraces are fundamental for food security, livelihoods, and culture. Nevertheless, genetic erosion (i.e., the loss of genetic diversity and variation in a [...] Read more.
Latin America is the center of domestication and diversity of maize, the second most cultivated crop worldwide. In this region, maize landraces are fundamental for food security, livelihoods, and culture. Nevertheless, genetic erosion (i.e., the loss of genetic diversity and variation in a crop) threatens the continued cultivation and in situ conservation of landrace diversity that is crucial to climate change adaptation and diverse uses of maize. We provide an overview of maize diversity in Latin America before discussing factors associated with persistence of large in situ maize diversity, causes for maize landrace abandonment by farmers, and strategies to enhance the cultivation of landraces. Among other factors, maize diversity is linked with: (1) small-holder farming, (2) the production of traditional food products, (3) traditional cropping systems, (4) cultivation in marginal areas, and (5) retention of control over the production system by the farmers. On the other hand, genetic erosion is associated with substitution of landraces with hybrid varieties or cash crops, and partial (off-farm labor) or complete migration to urban areas. Continued cultivation, and therefore on-farm conservation of genetic diversity held in maize landraces, can be encouraged by creating or strengthening market opportunities that make the cultivation of landraces and open pollinated varieties (OPVs) more profitable for farmers, supporting breeding programs that prioritize improvement of landraces and their special traits, and increasing the access to quality germplasm of landraces and landrace-derived OPVs. Full article
(This article belongs to the Special Issue Maize Breeding for Alternative and Multiple Uses)
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Open AccessArticle
Fibre and Seed Productivity of Industrial Hemp (Cannabis sativa L.) Varieties under Mediterranean Conditions
Agronomy 2021, 11(1), 171; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010171 - 18 Jan 2021
Viewed by 440
Abstract
Farmers’ interest in renewable raw materials such as hemp (Cannabis sativa L.) fibres has recently increased, but hemp productivity is strongly affected by genotype and environment conditions. A 3-year field experiment was conducted under Mediterranean environment in northern Greece to evaluate the [...] Read more.
Farmers’ interest in renewable raw materials such as hemp (Cannabis sativa L.) fibres has recently increased, but hemp productivity is strongly affected by genotype and environment conditions. A 3-year field experiment was conducted under Mediterranean environment in northern Greece to evaluate the productivity (regarding fibres and seeds) of six monoecious hemp varieties. The vars. Futura 75 and Bialobrzeskie provided the greatest (p < 0.01) fibre productivity (4.57 and 4.27 t ha−1, respectively), which were 77.1% and 65.5%, respectively, greater than that of the least productive var. Fedora 17. However, the vars. Santhica 27, Tygra and Bialobrzeskie provided the highest (p < 0.05) seed yield (2.7, 2.9 and 2.6 t ha−1, respectively), which were 28.6%, 38.1% and 23.8%, respectively, greater than that of the least productive var. Futura 75. Hemp fibre yield was strongly positively correlated with total biomass (R2 = 0.8612) and stem biomass yield (R2 = 0.9742), while it was inversely correlated with fibre strength (R2 = 0.424). Hemp seed yield was not correlated with the hemp plant density, height, total biomass or stem biomass yield. The six hemp genotypes evaluated in the study had Δ9-tetrahydrocannabinol (THC) content lower than 0.2% satisfying the European legislation requirements for industrial hemp varieties. The results of the study indicated that, under Mediterranean conditions (northern Greece), the var. Bialobrzeskie showed high productivity, as averaged across years, for both fibres and seeds. This result is very helpful for farmers which should prefer hemp varieties of dual-purpose production (stems and inflorescences or stems and seeds) adapted best to their local environment. Full article
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Open AccessArticle
Overexpression of Transcription Factor GmTGA15 Enhances Drought Tolerance in Transgenic Soybean Hairy Roots and Arabidopsis Plants
Agronomy 2021, 11(1), 170; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010170 - 18 Jan 2021
Viewed by 343
Abstract
Soybean (Glycine max) is one of the important oil crops worldwide. In recent years, environmental stresses such as drought and soil salinization have severely deteriorated soybean yield and quality. We investigated the overexpression of the transcription factor GmTGA15 in response to [...] Read more.
Soybean (Glycine max) is one of the important oil crops worldwide. In recent years, environmental stresses such as drought and soil salinization have severely deteriorated soybean yield and quality. We investigated the overexpression of the transcription factor GmTGA15 in response to drought stress in transgenic soybean hairy roots and Arabidopsis plants. The results of quantitative real time polymerase chain reaction (qRT-PCR) analyses showed that GmTGA15 was greatly induced by salt, PEG6000, salicylic acid (SA), gibberellic acid (GA), abscisic acid (ABA), and methyl jasmonate (MeJA) in soybean. In response to drought stress, the contents of both chlorophyll and proline were significantly increased, while the content of malondialdehyde (MDA) was significantly decreased in the soybean hairy roots with the overexpression of GmTGA15 in comparison to wild type (WT). Under the simulated drought conditions, the transgenic Arabidopsis plants showed significantly longer roots and lower mortality than that of the wild type. These results suggest that GmTGA15 promotes tolerance to drought stress in both soybean and Arabidopsis plants. This study provides the scientific evidence for further functional analysis of soybean TGA transcription factors in drought stress and the breeding of drought-resistance crops. Full article
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Open AccessArticle
Energy Potential of Agri Residual Biomass in Southeast Asia with the Focus on Vietnam
Agronomy 2021, 11(1), 169; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010169 - 18 Jan 2021
Viewed by 406
Abstract
Southeast Asia currently faces a huge increase in energy consumption and serious environmental issues. A widely underutilized and still unexplored potential of these countries lies in residual biomass. In the present research, the production quantities and energy yields of the most abundant agricultural [...] Read more.
Southeast Asia currently faces a huge increase in energy consumption and serious environmental issues. A widely underutilized and still unexplored potential of these countries lies in residual biomass. In the present research, the production quantities and energy yields of the most abundant agricultural byproducts in Vietnam, i.e., rice straw, rice husks, sugarcane bagasse and sugarcane trash, were calculated. Total crop yield, residues ratio and net calorific values of the wet basis biomass served as input parameters for the calculations. Moreover, the results were found for individual regions and provinces of the country. The findings show that the production of paddy rice straw is an enormous 97 million tons per year with an energy potential of over 380 TWh, as well as another 9 million tons yearly and 35 TWh in the case of rice husks. More than half of rice biomass production is concentrated in the Mekong River Delta region. Harvesting and processing of sugarcane annually generates about 5 million tons of bagasse and over 3.5 million tons of sugarcane trash with the total energy potential of about 27 TWh, which is primarily available in the central regions of Vietnam. The detailed laboratory determination of fuel-energy properties of studied materials, such as gross and net calorific value, volatile matter, ash and moisture content and contents of chemical elements was also carried out. Based on the research results and literature analysis, the possibilities of biofuel production and energy utilization of the above-mentioned residues are discussed. Full article
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Open AccessArticle
Experimental Investigation of Traction Power Transfer Indices of Farm-Tractors for Efficient Energy Utilization in Soil Tillage and Cultivation Operations
Agronomy 2021, 11(1), 168; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010168 - 17 Jan 2021
Viewed by 793
Abstract
Farm tractors in cultivation consume a big amount of fossil fuels and emit greenhouse gases to the atmosphere. Improving traction performance and power transfer indices of wheeled tractors and field terrain soil with higher traction (pull ability) at optimal travel reduction (TR) can [...] Read more.
Farm tractors in cultivation consume a big amount of fossil fuels and emit greenhouse gases to the atmosphere. Improving traction performance and power transfer indices of wheeled tractors and field terrain soil with higher traction (pull ability) at optimal travel reduction (TR) can optimize energy utilization. This study compares the traction performance, fuel consumption, and field productivity, of a farm tractor equipped with a new drive wheel “rigid lugged wheel (RLW)” and conventional tire wheel (CTW) in field tillage operations. Tractor with RLW resulted 24.6 kN drawbar pull and 6.6 km.h−1 travel speed at 80% tractive efficiency and 15.6% TR. While with CTW, the drawbar pull and the travel speed were 23.2 kN and 6.0 km h−1 respectively at 68% tractive efficiency and 36.3% TR. The RLW resulted in improved traction performance with similar equipment weight. Tractor with RLW also resulted 220.5% lower TR, 14.8% higher field productivity, and 15.4% lower fuel consumption. RLW can control equipment weight and field traffic intensity with the improved traction performance of wheeled tractors and will make the field operations more energy-efficient and economical. For enhanced field drivability of RLW, further work is required to test for diverse field conditions and differently sized tractors. Full article
(This article belongs to the Special Issue Life Cycle Sustainability Assessment of Agricultural Machinery)
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Open AccessArticle
Theoretical Foundation of the Control of Pollination by Hoverflies in a Greenhouse
Agronomy 2021, 11(1), 167; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010167 - 17 Jan 2021
Viewed by 620
Abstract
We propose a conceptual model for pollination and fertilization of tomato flowers in greenhouses crops by hoverflies, when the maximal number of adult pollinators maintained by the crops is less than what is needed for an economically successful pollination in greenhouses. The model [...] Read more.
We propose a conceptual model for pollination and fertilization of tomato flowers in greenhouses crops by hoverflies, when the maximal number of adult pollinators maintained by the crops is less than what is needed for an economically successful pollination in greenhouses. The model consists of a two-stage process for additional feeding of hoverfly to maintain the pollinator density at the economically desired level. First, with a stochastic model, we calculate the density of flies necessary for the economically successful pollination, determined according to the economically expected yield. Second, using a deterministic optimal control model, we find a minimum cost supplementary feeding strategy. In summary, we theoretically demonstrate, at the present stage of the research without validations in case studies, that optimal supplementary feeding can maintain the economically desired hoverfly density. Full article
(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)
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Open AccessArticle
Assessment of Energy Budgeting and Its Indicator for Sustainable Nutrient and Weed Management in a Rice-Maize-Green Gram Cropping System
Agronomy 2021, 11(1), 166; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010166 - 16 Jan 2021
Viewed by 511
Abstract
Sustainability and climate change are the two major challenges to the agricultural production system. The trade-off between them is essential for higher profitability. The energy assessment is essential for judging the sustainability and vulnerability of a production system. Besides, nutrient management and weed [...] Read more.
Sustainability and climate change are the two major challenges to the agricultural production system. The trade-off between them is essential for higher profitability. The energy assessment is essential for judging the sustainability and vulnerability of a production system. Besides, nutrient management and weed management are equally imperative to sustainability. Thus, the present study was executed to assess the energy balance, key energy indicators and profitability of rice–maize–green gram system under different nutrient and weed management practices. Application of Brassicaceous seed meal (BSM) along with mineral fertilizer attributed the highest rice (5.62 t ha−1) and maize (6.48 t ha−1) yield which was 11.6%, 8.3% and 3.7% in maize and 10.0%, 6.2% and 8.7% in rice for the conjoint application with vermicompost, farmyard manure (FYM) and neem cake, respectively. Moreover, BSM recorded the highest net energy gain, energy use efficiency and energy efficiency ratio and the lowest specific energy in all the crops. Application of pre-emergence herbicides followed by hoeing was found to be best in all respects including yield, profitability, energy use efficiency, energy effectiveness, etc. The appropriate combination of integrated nutrient management with BSM and pre-emergence herbicide application followed by hoeing provided an additional advantage not only in terms of yield but also an efficient use of energy, profitability and environmental safety. BSM and neem cake could be the alternative organic manure in the integrated nutrient-cum-weed management module and they could be able to compensate the paucity of FYM and vermicompost in the country. Full article
(This article belongs to the Special Issue Composting as Key Driver for Sustainable Agricultural Scenarios)
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Open AccessArticle
Potato Growth and Yield Characteristics under Different Cropping System Management Strategies in Northeastern U.S.
Agronomy 2021, 11(1), 165; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010165 - 16 Jan 2021
Viewed by 418
Abstract
Cropping systems and management practices that improve soil health may greatly enhance crop productivity. Four different potato cropping systems designed to address specific management goals of soil conservation (SC), soil improvement (SI), disease suppression (DS), and a status quo (SQ) standard rotation, along [...] Read more.
Cropping systems and management practices that improve soil health may greatly enhance crop productivity. Four different potato cropping systems designed to address specific management goals of soil conservation (SC), soil improvement (SI), disease suppression (DS), and a status quo (SQ) standard rotation, along with a non-rotation (PP) control, were evaluated for their effects on potato crop growth, nutrient, and yield characteristics under both irrigated and non-irrigated (rainfed) conditions in field trials in Maine, USA, from 2004 to 2010. Both cropping system and irrigation significantly (p < 0.05) affected most potato crop parameters associated with growth and yield. All rotations increased tuber yield relative to the non-rotation PP control, and the SI system, which included yearly compost amendments, resulted in overall higher yields and a higher percentage of large-size tubers than all other systems with no irrigation (increases of 14 to 90%). DS, which contained disease-suppressive green manures and cover crops, produced the highest yields overall under irrigation (increases of 11 to 35%). Irrigation increased tuber yields in all cropping systems except SI (average increase of 27–37%). SI also resulted in significant increases in leaf area duration and chlorophyll content (as indicators of photosynthetic potential) and root and shoot biomass relative to other cropping systems, particularly under non-irrigated conditions. SI also resulted in higher shoot and tuber tissue concentrations of N, P, and K, but not most micronutrients. Overall, cropping systems that incorporate management practices such as increased rotation length and the use of cover crops, green manures, reduced tillage, and particularly, organic amendments, can substantially improve potato crop growth and yield. Irrigation also substantially increased growth and yield under normal field conditions in Maine, but SI, with its large organic amendments, was essentially a substitute for irrigation, producing comparable results without irrigation. Full article
(This article belongs to the Special Issue Cropping Systems and Agronomic Management Practices of Field Crops)
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Open AccessArticle
Cover Crop and Pruning Residue Management to Reduce Nitrogen Mineral Fertilization in Mediterranean Vineyards
Agronomy 2021, 11(1), 164; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010164 - 16 Jan 2021
Viewed by 380
Abstract
This paper aimed to study the effect of temporary cover crop and vine pruning residue burial as alternative practices to conventional tillage on soil nitrate (NO3-N) availability and grapevine performance in the short term. The trial was carried out in a [...] Read more.
This paper aimed to study the effect of temporary cover crop and vine pruning residue burial as alternative practices to conventional tillage on soil nitrate (NO3-N) availability and grapevine performance in the short term. The trial was carried out in a rain-fed vineyard (Vitis vinifera L., cv Grecanico dorato/140 Ruggeri) located in a traditional Mediterranean viticultural area (37°32′48′′ N; 13°00′15′′ E) in Sicily (Italy). Conventional tillage (CT) soil management was compared with winter cover crop (CC), conventional tillage plus buried pruning residue (CT + PR), and winter cover crop plus buried pruning residue (CC + PR) management treatments. Two fertilizer treatments (92 kg ha−1 of N as urea and 0 kg ha−1) were applied to the four soil management treatments. Vicia faba L. was the selected leguminous cover crop species, which was seeded in autumn and buried in spring at the same time as vine pruning residues. The soil NO3-N content was monitored, and vine vegetative growth, yield, and must quality were assessed over two seasons. Results showed that NO3-N availability strongly differed between fertilized (F) and unfertilized (UF) plots and years and among treatments. A positive effect of winter leguminous CC + PR on the Grecanico dorato grapevine performance was observed. In the UF vineyard, grape fertility, yield, Ravaz index, and total soluble solids were significantly higher in CC + PR vines than in other treatments, thus showing the reliability of reducing N mineral fertilization and related risks of excess nitrate in groundwater. The possibility of increasing the overall sustainability of rain-fed vineyards in a semiarid agro-ecosystem, without negative effects on grape and must quality, is also demonstrated. Full article
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Open AccessArticle
Effect of Crop Residues on Weed Emergence
Agronomy 2021, 11(1), 163; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010163 - 16 Jan 2021
Viewed by 453
Abstract
Weed behaviour in crop fields has been extensively studied; nevertheless, limited knowledge is available for particular cropping systems, such as no-till systems. Improving weed management under no-till conditions requires an understanding of the interaction between crop residues and the seedling emergence process. This [...] Read more.
Weed behaviour in crop fields has been extensively studied; nevertheless, limited knowledge is available for particular cropping systems, such as no-till systems. Improving weed management under no-till conditions requires an understanding of the interaction between crop residues and the seedling emergence process. This study aimed to evaluate the influence of maize and wheat residues, applied in three different quantities (1, the field quantity, 0.5, and 1.5-fold amounts of the field quantity), on the emergence of eight weed species: Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Digitaria sanguinalis, Echinochloa crus-galli, Setaria pumila, Sonchus oleraceus, and Sorghum halepense. The experiment was conducted over two consecutive years. The results showed that the quantities 1 and 1.5 could suppress seedling emergence by 20 and 44%, respectively, while the quantity 0.5 seems to promote emergence by 22% compared with the control without residues. Weed species showed different responses to crop residues, from C. album showing 56% less emergence to S. halepense showing a 44% higher emergence than the control without residues. Different meteorological conditions in the two-year experiment also exhibited a significant influence on weed species emergence. Full article
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Open AccessArticle
Phytochemical and Functional Characterization of Phenolic Compounds from Cowpea (Vigna unguiculata (L.) Walp.) Obtained by Green Extraction Technologies
Agronomy 2021, 11(1), 162; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010162 - 16 Jan 2021
Viewed by 322
Abstract
This work presents a green, downstream process, from extraction to phytochemical characterization and bioactivity testing, to obtain and evaluate the functional properties of phenolic compounds from cowpea (Vigna unguiculata (L.) Walp.) seeds and pods. Phenolic-rich extracts were obtained by pressurized liquid [...] Read more.
This work presents a green, downstream process, from extraction to phytochemical characterization and bioactivity testing, to obtain and evaluate the functional properties of phenolic compounds from cowpea (Vigna unguiculata (L.) Walp.) seeds and pods. Phenolic-rich extracts were obtained by pressurized liquid extraction (PLE). The main factors affecting the extraction conditions (temperature and solvent) were optimized in order to attain extracts with the highest extraction yield, antioxidant capacity, and total phenolic content. The optimal extraction conditions were 1:1 ethanol:water at 170 °C with one extraction cycle for seeds and three extraction cycles for pods. Phenolic compounds of optimal extract were analyzed by UHPLC-q-TOF-MS/MS (quadrupole-time of flight tandem MS). The obtained PLE-extracts exhibited higher phenolic content and antioxidant activity compared to conventional extraction procedures. The in vitro anti-neurodegenerative potential of extracts was measured through Acetylcholinesterase (AChE) inhibition assay. The results revealed the higher bioactivity observed in cowpea pod samples compared to seed extracts, which might be related to higher levels of quercetin and quercetin glycosides, kaempferol diglucoside, and other tetrahydroxylated flavones and flavonols identified in these samples. These results also provide an added-value benefit to the cultivation of this legume, considering the high potential of cowpea phenolic extracts as nutraceutical and functional ingredients in food formulations. Full article
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Open AccessArticle
Contribution of Agro-Environmental Factors to Yield and Plant Diversity of Olive Grove Ecosystems (Olea europaea L.) in the Mediterranean Landscape
Agronomy 2021, 11(1), 161; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010161 - 16 Jan 2021
Viewed by 291
Abstract
Olive cultivation (Olea europaea L.) is one of the most significant sources of income for agricultural areas in the Mediterranean basin, and the olive oil industry as well as the environmental protection are an important part of the Greek agricultural sector. Generalized [...] Read more.
Olive cultivation (Olea europaea L.) is one of the most significant sources of income for agricultural areas in the Mediterranean basin, and the olive oil industry as well as the environmental protection are an important part of the Greek agricultural sector. Generalized Linear Models were applied in order to investigate the predictive strength of several biodiversity components and agro-environmental factors for yield and herbaceous plant diversity (species richness) in organic and conventional olive groves of Greece. Our study highlights an increase in yields of organic olive groves by increasing manure application and the earthworms’ density. In the conventional olive groves, yields increase by increasing soil organic matter and the application of inorganic fertilizer N. Also, the herbaceous plant species richness increases with increasing the Shannon diversity index of herbaceous plants, the field area, the application of organic fertilizer K and the manure in organic olive groves. As for the conventional ones, herbaceous plant species richness increases with the increase of the application of inorganic fertilizer N. Moreover, some plant species could be regarded as indicators of the differently managed olive groves. Conclusively, this study contributes to the integration of biodiversity conservation with ecologically sustainable agriculture and conservation of agroecosystem. Finally, it could be utilized as a decision and management tool to the scientific and agricultural community reinforcing the knowledge about the agro-environmental impact in olive grove management systems. Full article
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