查看更多>>摘要：? 2022 Elsevier B.V.Nitrogen (N) is an essential element that is required in the highest amounts by the arabica coffee (Coffea arabica L.) trees. The efficiency of N fertilization in coffee could be improved by the application of silicon (Si). Thus, the objective of this study was to evaluate the effect of foliar application of soluble Si and N fertilizer on nutrition, vegetative growth, fruit ripening, bean yield, and N-use efficiency of Arabica coffee. The experiment took place from 2013 to 2017 on an Arabica coffee plantation established on a sandy clay loam Acrisol of southeastern Brazil. It was arranged in a randomized complete block design with four replications. Treatments consisted of the combination of the presence and absence of foliar application of Si with four N rates (0–300 kg N ha?1 year?1). The foliar application of Si was performed by spraying stabilized silicic acid two times per growing season (Nov. and Feb.). The source of N used was ammonium nitrate (32% N), and it was split four times (Oct.–Feb.) each year. Nitrogen fertilization reduced the stoichiometric ratios among most other nutrients and N in coffee leaves, especially by increasing plant growth and leaf N concentration. In addition, it contributed to the maintenance of plant leafiness, besides increasing the percentage of ripe fruits and coffee bean yield. Despite having only little effect on the concentration and stoichiometry of nutrients in leaves and on plant growth, Si application increased the bean yield of coffee. This was particularly so under the highest N rates, as well as the agronomic efficiency of N applied to the crop in some conditions. Silicon also reduced the percentage of dry fruits in 2017 and increased the percentage of ripe fruits (2015 and 2017). In conclusion, spraying coffee with Si in form of stabilized silicic acid potentially improves the N-use efficiency in the crop.
查看更多>>摘要：? 2022 Elsevier B.V.As protein-rich crops, grain legumes are of great importance in organic farming. Common vetch (Vicia sativa L.) has not only a higher protein content than faba bean (Vicia faba L.) and pea (Pisum sativum L.) but also has lower requirements for soil and climatic conditions. The phenology of common vetch with the formation of high biomass requires cultivation in an intercropping system with a strong partner ensuring a stable crop stand for machine harvest of the grains. In this study, low- and high-growing common vetch cultivars were intercropped with short- and long-stemmed oats in different seed ratios to find the best combination of both. Therefore, a field trial was conducted at the Thünen Institute of Organic Farming in Northern Germany in a randomised block design with four replications over three years. The agronomic performance showed a slight inhibition in pod formation of vetches in long-stemmed oat mixtures. Furthermore, the high-growing vetch suppressed the short-stemmed oat more than the long-stemmed oat. The two different growth characters of oat had no effect on weed suppression. Moreover, the high-growing vetch showed better weed suppression over all seed ratios in comparison to the low-growing vetch due to its vigorous growth and higher crop height. The regression models showed a strong influence of the year on total and partial grain and protein yields. Long-stemmed oat mixtures had a higher total grain yield than short-stemmed oat mixtures. A comparison of the common vetch cultivars in long-stemmed oat-mixtures demonstrates a total grain yield advantage for mixtures of high-growing vetch (5.3 Mg ha?1 dry matter (d. m.) (2016)) than for low-growing vetch (5.0 Mg ha?1 d. m. (2016)) in seed mixtures with a 51.9 % and a 44.6 % share of vetch. In short-stemmed oat mixtures, total grain yields of 4.2 Mg ha?1 d. m. (2016) were estimated for the low-growing vetch as well as for the high-growing vetch in seed mixtures with a 48.8 % and a 33.6 % share of vetch, respectively. The total grain yields of intercropped common vetches were higher than the respective sole-cropped cultivars. According to the regression model, a maximum total protein yield of 1.0 Mg ha?1 d. m. (2014 and 2015) was estimated for the high-growing vetch in a seed mixture with 79.8 % (2014) and 59.6 % (2015) share of vetch in short- and long-stemmed oat, respectively. The low-growing vetch had the highest total protein yields of 0.8 Mg ha?1 d. m. (2016) in short-stemmed oat mixtures with a 61.9 % share of vetch in the seed mixture. When intercropped with long-stemmed oat, the total protein yield of low-growing vetch-mixtures was lower with 0.7 Mg ha?1 d. m. (2016) in a seed mixture with a 59.6 % share of vetch. Mixtures showed a total grain yield advantage for high-growing vetches in both oat cultivars. Seed mixtures with a 34–64 % share of vetch reached the highest total grain yields. High total protein yields were reached in seed mixtures with higher vetch shares of 58–83 % for the high-growing and 60–95 % for the low-growing vetch. However, the risk of collapse of crop stand increased with high precipitation and high shares of vetch in the seed mixture which makes a machine harvest for grain yield challenging. Therefore, a seed mixture with a 50 % share of vetch is recommended to reach high levels of grain and protein yield but also to prevent an overgrowth of the cereal.
查看更多>>摘要：? 2022Climate variability and extremes adversely impacts Australian cotton crop production and imposes a major constraint on farm planning, industry supply chains and resource allocation. This study reviews time-series yield and crop production methods to account for climate, as well as perform a cotton yield and climate time series analysis using rainfall and temperature data. This study demonstrates that dryland lint yield gains during average-to-moderate rain/temperature years while irrigated lint yields have improved during more frequent average rain/hot growing seasons (1997–2018). Results also discovered climate in central cotton growing areas is impacted by El Ni?o Modoki and Ni?o4 indices and the various phases of ENSO. These findings translate into meaningful actions for industry adaptation and in turn provide a valuable step in accounting for climate variability and yield related inputs such as fertiliser and water resources.
查看更多>>摘要：? 2022 Elsevier B.V.This study evaluated the canopy dynamics of three lucerne (Medicago sativa L.) genotypes of different fall dormancy (FD) ratings when grown under three contrasting defoliation regimes over five regrowth seasons at Lincoln University, Canterbury, New Zealand. Crops were sown in October 2014 in a split-plot design with main plots as defoliation frequencies (28 days [DF 28], 42 days [DF 42] and 84 days [DF 84]) and genotypes as subplots. Genotypes varied in fall dormancy (FD) rating and were classified as dormant (cv. AgR Palatable, FD2), semi-dormant (cv. Grassland Kaituna, FD5), or non-dormant (cv. SARDI 10, FD10). All crops were grown through an establishment phase until January 2015, when defoliation treatments were imposed. The experiment terminated in May 2019. Defoliation treatments were imposed from early spring (August-September) to autumn (May) with a single clean-up graze in late June/July. Defoliation frequency x genotype interactions showed FD10 was the most productive in regrowth season 1 but least persistent and productive in regrowth season 5, particularly under the DF 28 and DF 42 treatments. Results suggest different partitioning responses amongst genotypes. In a decreasing photoperiod, the growth rate of FD2 decreased by 0.77 ± 0.07 kg DM ha?1 °Cd?1 compared with 0.67 ± 0.09 kg DM ha?1 °Cd?1 for FD5 and FD10. However, FD10 showed no response to an increasing photoperiod under the DF28 defoliation regime. The lower rate of partitioning to perennial biomass of FD10 was suggested by the rapid decline in shoot density (?0.000112 shoot m?2 °Cd?1) over time compared with ? 0.000049 shoot m?2 °Cd?1 for FD2 and FD5. FD10 had heavier individual shoot mass over the last two years, but its canopy plasticity was insufficient to control the shoot size/density balance, so there was greater weed ingress. The DF 84 treatment enabled FD10 to produce > 15 t DM ha?1 year?1 over the five regrowth seasons, which was not different to FD2 and FD5. Under more frequent defoliations, FD2 and FD5 were more persistent and had higher yields than FD10.
查看更多>>摘要：? 2022Root system architecture (RSA) is important in optimizing the use of nitrogen. High-throughput phenotyping techniques may be used to study root system architecture traits under controlled environments. A root phenotyping platform, consisting of germination paper-based pouch and wick coupled with image analysis, was used to characterize root seedling traits in 30 landrace-derived bread wheat genotypes and the bread wheat parent Paragon under hydroponic high N (HN) and low N (LN) conditions. In addition, two glasshouse experiments under HN and LN conditions were carried out to measure whole plant performance including flag-leaf photosynthetic rate, N uptake and biomass per plant for 13 wheat genotypes of which eight were common with those in the root phenotyping hydroponic experiment. There were significant differences in RSA traits between genotypes for seminal root number per plant, lateral root number per plant, seminal root length per plant and seminal root angle, with transgressive segregation for landrace-derived lines above the elite parental cultivar Paragon under HN and LN conditions. In the glasshouse experiments, genetic variation in flag-leaf photosynthesis rate was found in landrace-derived genotypes in the range 25.9–33.3 μmol m?2 s?1 under HN and in N uptake in the ranges 0.37–0.48 g N plant?1and 0.21–0.30 g plant?1 under HN and LN conditions, respectively (P < 0.05), with transgressive segregation above Paragon. Plant Nitrogen Nutrition Index also showed transgressive segregation in the landrace-derived lines above Paragon under HN and LN conditions. Greater maximum root depth and more lateral roots per plant in the hydroponic screen were each correlated with increased biomass per plant under LN conditions. Results from this study demonstrated genetic variation for seedling RSA traits in landrace-derived lines above the elite parental cultivar Paragon, which potentially could be utilized to improve N-use efficiency in breeding programmes.
查看更多>>摘要：? 2022 Elsevier B.V.In the Hokkaido region of Japan, a new japonica-type high-yielding rice variety (HYV), Kitagenki, demonstrated higher grain yield than the early developed japonica-type HYVs; however, its yield potential is unknown. Therefore, a four-year (2015–2018) field study was conducted to elucidate the (1) yield potential of Kitagenki, (2) effect of early and late nitrogen (N) applications on the grain yield of Kitagenki, and (3) effect of early N application and planting density on the grain yield of Kitagenki. Experiment 1 consisted of three early N (10.5 N: basal 10.5 g N m?2, 16.5 N: basal 16.5 g N m?2, and 10.5 N + T1: basal 10.5 g N m?2 with topdressing of 6 g N m?2 at the panicle formation stage) combined with two late N (? T2: no topdressing at the full-heading stage, and + T2: topdressing of 6 g N m?2 at the full-heading stage) applications. Experiment 2 consisted of two early N (10.5 N and 16.5 N) applications combined with two planting densities (standard planting: 22.8–23.0 hill m?2 and sparse planting: 11.4–11.5 hill m?2). The yield potential of Kitagenki was approximately 1200 g m?2 of gross hulled grain, which is the highest yield recorded among japonica-type HYVs cultivated in Japan. In experiment 1, the grain yield of Kitagenki was improved by both early N (16.5 N, 10.5 N + T1 > 10.5 N) and late N (+ T2 > ? T2) applications owing to the improved sink capacity and source ability. We suggest 10.5 N + T1 + T2 and 16.5 N + T2 as the optimum combination of early and late N applications to stably maximize the grain yield of KG. In experiment 2, the grain yield of KG was significantly improved by early N (16.5 N > 10.5 N) application but not significantly by planting density. In 16.5 N, sparse planting tended to produce a higher grain yield by lowering the lodging scores and increasing the source-sink ratio compared to those obtained with standard planting. Therefore, we suggest 16.5 N sparse planting as the optimum combination of early N application and planting density to stably maximize the grain yield of Kitagenki.
查看更多>>摘要：? 2022 Elsevier B.V.The expanded use of water-intensive crops, such as maize, has exacerbated soil drying and water scarcity in watersheds with large irrigated surfaces. As we face climbing drought risks, water can be conserved in such areas by adopting agricultural systems that limit water deficits at the watershed level. In this study, integrated modeling was used to assess how different approaches to cultivating irrigated maize influenced water balance in France's Aveyron watershed, which experiences strong and recurrent water deficits. Ten-year simulations were performed using the MAELIA model, which can simulate at fine-scale spatial and temporal interactions among agricultural activities, the functioning of soil-crop systems, hydrological dynamics, and water resource management. Three specific scenarios were modeled in addition to the benchmark situation representing current management practices: 1) maize irrigation was carried out on an as-need basis, where all farms were equipped with a decision?support tool for assessing water stress in real time; 2) maize monocultures were replaced by a wheat/maize succession; and 3) the two previous scenarios were combined. In the first two scenarios, irrigation withdrawal volumes declined substantially, eliminating approximately 30 % of the watershed's water deficit due to a better scheduling of the irrigation to the needs and by the replacement of maize by wheat with lower water requirements. There was also a slight increase in river flow rates in the summer and a slight decrease in annual drainage. The third scenario went even further in lowering withdrawal volumes and increasing flow rates thanks to additive effects: withdrawal volumes declined by 28 %, and river flow rates increased by 4 %. This study demonstrated that combining water-saving practices with crop diversification holds promise for limiting water deficits in irrigated watersheds while having a negligible impact on crop yields. It also demonstrated the usefulness of a multiagent integrated modeling platform that can conduct simulations at fine levels of spatial and temporal resolution on both agronomic and hydrologic aspects
查看更多>>摘要：? 2022 The AuthorsThe preservation of nutrient capital, soil fertility, and carbon (C) sequestration capacity in Mediterranean olive groves requires evaluation of agricultural practices beyond short-term productivity. We aim to contribute with a mechanistic understanding on the effects that the preservation of herbaceous cover and the use of chemical fertilizers have on the performance of olive trees and on the biogeochemical cycles of the agroecosystem. We compared nutrient fluxes and aboveground leafy stocks in an olive grove that had been organically managed for more than 60 years, in a treatment in which the annual spontaneous herbaceous cover was maintained (H), and after two years of shift to conventional management treatments in which the growth of herbaceous vegetation was avoided by the use of herbicides (NH), and where exclusion of the herbaceous cover is also combined with the supply of mineral fertilizers (NHF). Maintenance of herbaceous vegetation in H contributed to the retention of a high aboveground capital of C and nutrients, particularly nitrogen, (N), phosphorus (P) and potassium (K) that were about 2.9, 3.9 and 7.4 times greater than in NH, respectively. The permanence of herbaceous cover stimulated olive tree leaf litter decomposition rates by about 86 % and increased nutrient release. However, the H treatment led to a 37 % decrease in olive yield and lowered olive foliar N and P content as negative short-term effects. The addition of fertilizers (N, P, K, and Mg) in mineral and solid form in NHF resulted inefficient to improve olive tree nutritional status and olive production, and decelerated olive tree litter decomposition rates by 21 % and nutrient release. The nutrient retention in organic forms in the fast-growing species of herbaceous covers and the progressive nutrient release as litter decomposes may contribute to regulate and better adapt nutrient availability to the nutrient requirements of olive trees.
查看更多>>摘要：? 2022 Elsevier B.V.Biodegradable films are considered an environmentally-friendly alternative to traditional polyethylene (PE) film mulches, as they effectively reduce film pollution in the farmland when using mulched drip irrigation. However, the effects of different degradable films on soil micro-climate and maize growth have not been examined, especially under different irrigation amounts, which are critical considerations for oasis agriculture in arid areas. Therefore, we conducted a field study in 2019–2020 on maize farmland using two biodegradable films, one with an 80-day induction period (M80) and the other with a 100-day induction period (M100), and compared them with traditional PE film (MPE). Four irrigation amounts (4875, 5250, 5625, and 6000 m3 ha?1) were tested. Our results showed that weight loss rates of M80 and M100 were 7.21 times and 9.63 times higher than that of MPE, and this degradation process was slowed down with increased irrigation amounts. We attribute this mitigation to changes in soil moisture and the physiological characteristics of the crop. Using film of higher resilience together with higher irrigation amount resulted in more active photosynthesis and fluorescence, especially at the later maize growth stage, and improved maize yield compared to the other degradable film. In addition, the reduction in maize yield caused by the use of biodegradable films could be largely compensated for by applying higher irrigation amounts. Our findings recommend using M100 with an irrigation amount of 5625 m3 ha?1 for maintaining maize yields while reducing plastic pollution.
查看更多>>摘要：? 2022 Elsevier B.V.Crop simulation models are indispensable tools that facilitate studies involving yield impacts, adaptation and management strategies, and policy analysis. However, uncertainty among models with respect to climate change factors varies with location according to genetic, site and management differences. This study aims to evaluate the accuracy of three process-based soybean models, GLYCIM, SoySim, and DSSAT CSM-CROPGRO-Soybean, which vary in representation of soil-water-plant components, with respect to soybean growth, development, and seed yield for multiple varieties and at different locations under current and projected climates. Experimental data from the United States Mississippi Delta region including 156 site-year-cultivar-irrigation combinations were used. Sensitivity analyses with respect to climate change scenarios involving increasing air temperature and CO2 on yield were also conducted using mean model ensemble values. Statistical criteria for estimating the goodness-of-fit of the models were Wilmott's index of agreement (IA) and root mean square error (RMSE). Simulated seed yield RMSE across all validated datasets was 0.92 Mg ha?1 or lower, with GLYCIM and CROPGRO exhibiting the best values. A similar pattern was observed for IA, which ranged between 0.82 and 0.65. Simulated yield in response to climate change factors increased by 8.8% per 100 ppm CO2 on average, and declined 4.8% per °C. Although both GLYCIM and CROPGRO models simulated yield reductions between 0.4%, and 7.2%, the SoySim model predicted positive impacts (+3.7% and + 12.1%) under two climate scenarios (?T = 1.5 °C, CO2 = 423 ppm; ?T = 2.0 °C, CO2 = 478 ppm). Given the difference in model structure and predictions, a multi-model ensemble approach is recommended to assess global crop production under future climate conditions along with continued improvement in model heat stress sensitivity and CO2 response. However, model improvements are still required to improve accuracy with regards to genetic x management x environmental interactions.
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