Crop Yield Stability Research Articles

Crop Yield, Nitrogen Recovery, and Soil Mineral Nitrogen Accumulation in Extremely Arid Oasis Cropland under Long-Term Fertilization Management

Crop yield stability and soil mineral nitrogen (Nmin) have rarely been evaluated from a long-term perspective in the extremely arid cropland regions of China. Therefore, a nationwide experiment aimed to optimize fertilizer application and increase productivity and nitrogen use efficiency in gray desert soils was initiated in 1990. Eight combinations of chemical fertilizers (CK, N, NK, NP, and NPK), straw return (NPKS), and manure amendments (NPKM and NPKM+) were tested for 24 years on spring wheat, winter wheat, and maize. The results displayed that the yield of three crops from balanced fertilizer treatments (NPK, NPKS, NPKM, and NPKM+) did not differ significantly after 24 years; however, reliable yield stability due to lower coefficient of variation (CV) and higher nitrogen harvest index (NHI) were recorded for manure amendment treatments. Compared to NPKM, NHI was lower for the NPKM+ treatment, but crop yield and stability did not improve, suggesting that the appropriate choice for manure amendment is important for guaranteeing food security in extremely arid regions. Balanced fertilizer treatments resulted in lower Nmin residual in the 300 cm soil profile, compared to unbalanced fertilizer treatments. The NPKS treatment gave the lowest value. In the 0–100 cm soil profile, Nmin was higher in NPKM than in the NPK treatment, suggesting that straw or manure amendment can effectively maintain Nmin in the topsoil undercurrent cropland management in arid areas. The NPKM treatment had the highest crop nitrogen recovery rate and the lowest nitrogen losses, further illustrating that manure amendment has higher N retention potential. Overall, although Nmin residues are relatively high in these regions, balanced fertilizer treatments, especially NPKM and NPKS, are the optimum strategies in extremely arid regions.

Unsaturated soil shear strength of agricultural soils influenced by reclamation sequences in coastal China

AbstractAgricultural activities have raised increasing concern regarding their effects on soil properties and shear strength, which are related to root growth, crop yield and engineering stability. We collected undisturbed soil samples (0‐15 cm) from a No‐Reclaimed (NR) system, a Short‐term Reclaimed (SR) system for less than 7 years, and a Long‐term Reclaimed (LR) system for more than 30 years, in coastal reclamation areas. Direct shear tests were performed and soil water characteristic curves (SWCC) were developed for undisturbed soil samples at 96 soil sampling sites across five transects. Principal component analysis (PCA) was used to quantify tillage effects on soil properties and unsaturated shear strength including effective cohesion (c'), effective friction angle (φ'), and friction angle related with matric suction (φb). The LR system had significantly increased percentage clay and silt, organic matter (OM), microaggregates, gravity mean diameter (GMD) and effective cohesion (c'), but significantly decreased percentage sand, cation content and electricity conductivity (EC1:5). The SR system had increased OM and GMD compared to the NR system. c' and φb were significantly positively correlated with bulk density (ρb), clay, silt, OM and GMD. The correlations between the internal friction angle and these properties were opposite to those of cohesion. Two principal components (PC1 and PC2) explained the majority of the soil variables. PC1 had a strong relationship with clay, silt, OM, c' and sand, while PC2 had a strong relationship with EC1:5, SAR, GMD and ρb. Thus, PC1 can be regarded as an indicator of soil texture; similarly, PC2 was able to represent soil salinity properties and structure. Confidence ellipses significantly separated the differences in soil between different reclaimed systems. The use of principal components (PCs) in the linear regression reduced the variables and estimated c' and φ' accurately. This study increases the current understanding of the relationship between soil properties and shear strength under different tillage systems, and assesses the efficacy of soil property evaluation after reclamation in coastal areas.Highlights Effect of reclamation on soil properties and unsaturated shear strength was investigated. Long‐term reclamation increased unsaturated shear strength significantly. Soil properties are well explained by principal components (PC1 and PC2). Principal component regression is recommended for predicting unsaturated soil shear strength.

Evaluation of Moisture Regime on Agronomic Traits of Rice Genotypes

Drought stress is a major constraint to the production and yield stability of crops. Rice (Oryza sativa L.) is one of the most important cereals and considered as a drought sensitive crop species. A field experiment was conducted in the vinylhouse of the Department of Agronomy, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh, during March - August 2018 to evaluate the performance of 38 rice genotypes under control and drought conditions. The experiment was laid out in a completely randomized design containing two water regimes with three replications. The water regimes were well-watered and induced moisture stress conditions. Multivariate and principal components analyses revealed that different plant characters, viz. plant height, total tillers hill-1, panicle number hill-1, length of panicle, filled grains panicle-1, 1000-grain weight, grain yield plant-1 and straw weight plant-1 showed a wide range of variation due to variation in moisture level. Correlation study and biplot analysis considering PC1 and PC2 explained that grain yield was positively correlated with filled grain panicle-1, total tiller hill-1, panicle number hill-1 and 1000-grain weight. Based on the grain yield plant-1 (g) and others agronomic characters, the genotypes BU Acc 33 (26.68 g), BU Acc 30 (21.81 g), and BU Acc 21 (20.58 g) were identified as promising genotypes for developing drought tolerant variety (ies). Ann. Bangladesh Agric. (2021) 25 (1) : 89-104

Increasing soil organic carbon sequestration and yield stability by no‐tillage and straw‐returning in wheat–maize rotation

AbstractKnowledge about the changes in soil organic carbon (SOC) stocks and grain yields under different field management practices is necessary for achieving agricultural sustainability. An 8‐yr experiment for testing different tillage and straw management practices was conducted in a wheat (Triticum aestivum L.)–maize (Zea mays L.) rotation system in the southern Loess Plateau of China. Three tillage methods (control with no‐tillage and straw removal [CK], no‐tillage with straw stubbles 30–40 cm in height [NT], and rotary tillage with straw incorporation [RT]) were applied before maize planting, and two straw treatments (straw return [SR] and no straw return [SR0]) were applied after maize harvest. Over the 8 yr, SOC stocks exhibited similar dynamic changing trends in all treatments but were higher under NT, RT, and SR than under CK‐SR0. Compared with the initial soil, SOC stock increased the most (34.1%) in NT‐SR. Compared with the CK‐SR0, the NT‐SR, RT‐SR, CK‐SR, NT‐SR0, and RT‐SR0 increased wheat grain yields by 47.2, 36.8, 24.9, 25.1, and 20.0%, respectively. Similar trends were found for maize grain yields. The NT, RT, and SR increased crop yield stability with the highest sustainable yield index in NT‐SR for both wheat (.67) and maize (.70). Overall, the combination of no‐tillage with wheat straw stubbles 30–40 cm in height and maize straw return was the best strategy for improving SOC stocks, grain yields, and agricultural sustainability for grain production in dry, sub‐humid areas of northwestern China.

Conservation agriculture for increasing productivity, profitability and water productivity in rice-wheat system of the Eastern Gangetic Plain

There are increasing concerns about the negative effects of conventional tillage (CT), extreme climate events, increased weed incidence, and reduced availability of farm inputs on crop yield and yield stability, profitability, and water productivity in rice-wheat (R−W) systems of the Eastern Gangetic Plains (EGP) in South Asia. Conservation agriculture (CA)-based tillage practices have been proposed in the region to address these concerns. We analysed 84 on-farm trials’ data comparing CA-based practices with farmers’ CT practices in R−W systems of eastern Terai region of Nepal in the EGP. The objectives were to investigate crop and cropping systems productivity, profitability, yield stability, irrigation (WPi) and total water productivity (WP(r+i)), and fertilizer-use efficiencies of three CA- and one CT-based practices in R−W systems. Treatments included: (i) CT-based: puddled transplanted rice - conventional tillage wheat (PTR−CTW); (ii) CA-based: PTR − zero tillage wheat (PTR−ZTW); (iii) CA-based: direct-seeded rice − ZTW (DSR−ZTW); and (iv) CA-based: un-puddled transplanted rice − ZTW (UPTR−ZTW). Results showed that although there were no significant differences in yield of either rice or wheat or R−W system between CA-based and CT treatments, there was a significant reduction in production cost (by 245−369 USD ha−1) mainly due to reduced labor use and increased net gain (188−223 USD ha−1) in all CA-based R−W system. DSR−ZTW showed the highest yield stability and net profit, demonstrating its adaptability in the region. Among the irrigation applicators (35%) in rice, DSR used 107 mm (67 mm higher than PTR) irrigation water with WPi of 70% and 96% of PTR and UPTR, respectively due to the need of additional irrigation for crop establishment. In contrast, among the irrigation applicators (75%) in wheat, due to earlier sowing of ZTW, it required 18% less irrigation water resulting in 9% higher WPi compared to CTW. However, a follow-up study two years after completion of field trials revealed that no local farmers had continued CA-based practices mainly due to high weed pressure, lack of land leveling, inaccessibility of zero-till (ZT) drill machines, and lack of ZT service providers. Effective support systems incentivizing in land leveling, ZT machines, technical knowledge dissemination, and the development of integrated weed management practices for scaling-out strategies are essential to adopt CA-based practices. As the results have great implications to reduce production costs and increase farm profits, save energy and water, increase land and labor productivity, and improve food security of millions of smallholder farmers in the EGP, strong policy support to incentivize farmers to avoid the adoption barriers of CA-based practices is required.

Implementation of Epigenetic Variation in Sorghum Selection and Implications for Crop Resilience Breeding.

Crop resilience and yield stability are complex traits essential for food security. Sorghum bicolor is an important grain crop that shows promise for its natural resilience to drought and potential for marginal land production. We have developed sorghum lines in the Tx430 genetic background suppressed for MSH1 expression as a means of inducing de novo epigenetic variation, and have used these materials to evaluate changes in plant growth vigor. Plant crossing and selection in two distinct environments revealed features of phenotypic plasticity derived from MSH1 manipulation. Introduction of an epigenetic variation to an isogenic sorghum population, in the absence of selection, resulted in 10% yield increase under ideal field conditions and 20% increase under extreme low nitrogen conditions. However, incorporation of early-stage selection amplified these outcomes to 36% yield increase under ideal conditions and 64% increase under marginal field conditions. Interestingly, the best outcomes were derived by selecting mid-range performance early-generation lines rather than highest performing. Data also suggested that phenotypic plasticity derived from the epigenetic variation was non-uniform in its response to environmental variability but served to reduce genotype × environment interaction. The MSH1-derived growth vigor appeared to be associated with enhanced seedling root growth and altered expression of auxin response pathways, and plants showed evidence of cold tolerance, features consistent with observations made previously in Arabidopsis. These data imply that the MSH1 system is conserved across plant species, pointing to the value of parallel model plant studies to help devise effective plant selection strategies for epigenetic breeding in multiple crops.

Dissecting the Genetics of Early Vigour to Design Drought-Adapted Wheat.

Due to the climate change and an increased frequency of drought, it is of enormous importance to identify and to develop traits that result in adaptation and in improvement of crop yield stability in drought-prone regions with low rainfall. Early vigour, defined as the rapid development of leaf area in early developmental stages, is reported to contribute to stronger plant vitality, which, in turn, can enhance resilience to erratic drought periods. Furthermore, early vigour improves weed competitiveness and nutrient uptake. Here, two sets of a multi-reference nested association mapping (MR-NAM) population of bread wheat (Triticum aestivum ssp. aestivum L.) were used to investigate early vigour in a rain-fed field environment for 3 years, and additionally assessed under controlled conditions in a greenhouse experiment. The normalised difference vegetation index (NDVI) calculated from red/infrared light reflectance was used to quantify early vigour in the field, revealing a correlation (p < 0.05; r = 0.39) between the spectral measurement and the length of the second leaf. Under controlled environmental conditions, the measured projected leaf area, using a green-pixel counter, was also correlated to the leaf area of the second leaf (p < 0.05; r = 0.38), as well as to the recorded biomass (p < 0.01; r = 0.71). Subsequently, genetic determination of early vigour was tested by conducting a genome-wide association study (GWAS) for the proxy traits, revealing 42 markers associated with vegetation index and two markers associated with projected leaf area. There are several quantitative trait loci that are collocated with loci for plant developmental traits including plant height on chromosome 2D (log10 (P) = 3.19; PVE = 0.035), coleoptile length on chromosome 1B (–log10 (P) = 3.24; PVE = 0.112), as well as stay-green and vernalisation on chromosome 5A (–log10 (P) = 3.14; PVE = 0.115).

ВЛИЯНИЕ РЕГУЛЯТОРОВ РОСТА НА ДИНАМИКУ НАКОПЛЕНИЯ ПЛОЩАДИ ЛИСТОВОЙ ПОВЕРХОСТИ И ФОТОСИНЕТИЧЕСКОГО ПОТЕНЦИАЛА КОРМОВОЙ СВЕКЛЫ В УСЛОВИЯХ НЕЧЕРНОЗЕМНОЙ ЗОНЫ РФ

Intensification of agricultural production provides for the development and introduction of new, progressive and cost-effective techniques. In the Non-Chernozem zone of the Russian Federation, the issue of increasing the productivity of forage crops with high quality indicators that provide the livestock industry with juicy feeds is extremely acute. One of the ways to obtain a guaranteed high, stable crop yield, on the example of fodder beet experiencing a number of stressful situations during the growing season, is the use of modern, highly effective growth regulators that positively affect the growth and development of the crop. The research was carried out on the basis of the experimental field of the Kaluga branch of the RSAU – MTAA named after K.A. Timiryazev in 2019-2020 on sod-podzolic sandy loam soil in the Kaluga region on fodder beet of the Eckendorf yellow variety type. The aim of the study was to study the influence of various growth regulators on the dynamics of leaf surface growth, photosynthetic potential of fodder beet in the Non-Chernozem zone. The positive effect of the use of growth regulators on crop yield was established, the effect of seed pickling was 26,5-62 t/ha or 4,9-11,5%, with foliar application of 22,5-66 t/ha or 4,2-12,3%, the dynamics of the accumulation of the leaf surface area by the time of full ripeness increased by 4.1-12.3% and 1.8–10.0%, respectively, according to the application options in the culture cultivation technology relative to the control.

Identifying the dynamic evolution and feedback process of water resources nexus system considering socioeconomic development, ecological protection, and food security: A practical tool for sustainable water use

Abstract. The accelerated consumption of water resources caused by the rapid increase in population and urbanization is intensifying the complex interactions across water resources, socioeconomic development, ecological protection, and food security (WSEF), which causes not only the imbalance between water supply and demand but also the vulnerability of both food and ecological systems. Therefore, identifying the dynamic coevolution and feedback process is one of the most crucial ways of achieving the goal of sustainable water use. In this study, we developed an integrated modeling framework to better identify the dynamic interaction and coevolution process of the nexus across WSEF systems in the context of sustainable water uses by coupling system dynamic (SD) model and multi-objective optimization model. The SD model is used to simulate both the dynamic interaction of each agent and the coevolution process of the whole nexus system by positive/negative feedback loops. The multi-objective optimization model is used to quantify the negative feedback loops of the SD model by generating the optimal scheme of different water users. Finally, the model uncertainty considering different weighting factors is analyzed. The framework is applied to the upper reaches of the Guijiang River basin, China. Results show that (i) the rapid economic growth increases the conflict between the water uses for socioeconomic development and ecological protection, intensifying the ecological awareness and resulting in more water shortages of socioeconomic and food agents, which is unable to support such rapid development. (ii) Once the economic growth rate decreases, water resources are able to support economic development with a decreased overload index and stable crop yield, which further contributes to water sustainability. (iii) The river ecological agent is the critical factor that affects the robustness of the model. (iv) The equal consideration of each water usage is the most beneficial to sustainable development. These results highlight the importance of water resources management, considering the tradeoffs across multiple stakeholders, and give a strong reference to policymakers for comprehensive urban planning.

Solution of A Complex of Problems of Operational Planning And Management In The Conditions of A Mining Landmark In Azerbaijan

The main direction of the economic and social development of the Republic of Azerbaijan is the intensification of agricultural production. Irrigation is a powerful means of intensifying agricultural production in the context of its specialization. In areas with insufficient moisture (especially typical for mountainous areas), irrigation is one of the decisive factors in growing high and stable crop yields. This requires the development of new technical solutions and the introduction of automated systems for low-intensity irrigation of agricultural crops that meet the requirements of ecology and environmental protection of their habitat, which makes it possible to improve the ecological state of irrigated lands and reduce water consumption. per unit of production and increasing the yield of individual crops in irrigated fields.

Assessment of yield, plasticity and stability of spring barley cultivars grown in the European North of the Russian Federation

In recent years, modern agroclimatic environmental conditions in the European North of the Russian Federation are determined by constant fluctuations of biotic and abiotic factors, which require a high level of plasticity and stability of crop yield and quantitative characteristics from cultivars used in agricultural production. Therefore, determining the plant response to changing environmental factors in order to select the most promising breeding seeds, is an important task for breeders. The research was conducted on experimental field of N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences, in the nursery of competitive variety testing in 20172019. Cultivars of spring barley of local selection were studied. Indicators of cultivar plasticity and stability were calculated by the method of S.A. Eberhart, W.A. Rassell (1966), the indicator of genetic flexibility by the method of R.A. Udachin (1990). Various weather conditions during the research period enabled to evaluate the breeding material comprehensively. The hydrothermal coefficient (according to G.T. Selyaninov) varied from 1.85 to 3.06 during the research years. Ten cultivar samples of spring barley were analyzed to identify a plastic stable genotype. As a result, a high level of stability was shown by samples k-037712 (Ϭ2 = 0.01), k-038404 (Ϭ2 = 0.02). Samples with a neutral genotype were identified: k-039257, k-036982 (bi 1) and a sample weakly responding to environmental changes k-038806 (bi = 0.23). The bi value is very close to 1 in Kotlassky cultivar, which shows a high ecological plasticity. Sample k-038806 has the lowest coefficient of linear regression (0.23), therefore, it is suitable for cultivation on unfertilized soils. The selected genetic sources will be used in breeding to develop highly productive cultivars of spring barley for the conditions of the European North of the Russian Federation.

Optimum Planting Density Improves Resource Use Efficiency and Yield Stability of Rainfed Maize in Semiarid Climate.

Increasing planting density is an effective strategy for improving maize productivity, but grain yield does not increase linearly with the increase in plant density, especially in semiarid environments. However, how planting density regulates the integrated utilization of key input resources (i.e., radiation, water, and nutrients) to affect maize production is not clear. To evaluate the effects of planting density and cultivar on maize canopy structure, photosynthetic characteristics, yield, and resource use efficiency, we conducted a successive field experiment from 2013 to 2018 in Heyang County (Shaanxi Province, China) using three different cultivars [i.e., Yuyu22 (C1), Zhengdan958 (C2), and Xianyu335 (C3)] at four planting densities [i.e., 52,500 (D1), 67,500 (D2), 82,500 (D3), and 97,500 (D4) plants ha–1]. Increasing planting density significantly increased the leaf area index (LAI) and the amount of intercepted photosynthetically active radiation (IPAR), thereby promoting plant growth and crop productivity. However, increased planting density reduced plant photosynthetic capacity [net photosynthetic rate (Pn)], stomatal conductance (Gc), and leaf chlorophyll content. These alterations constitute key mechanisms underlying the decline in crop productivity and yield stability at high planting density. Although improved planting density increased IPAR, it did not promote higher resource use efficiency. Compared with the D1 treatment, the grain yield, precipitation use efficiency (PUE), radiation use efficiency (RUE), and nitrogen use efficiency (NUE) increased by 5.6–12.5%, 2.8–7.1%, and −2.1 to 1.6% in D2, D3, and D4 treatments, respectively. These showed that pursuing too high planting density is not a desirable strategy in the rainfed farming system of semiarid environments. In addition, density-tolerant cultivars (C2 and C3) showed better canopy structure and photosynthetic capacity and recorded higher yield stability and resource use efficiency. Together, these results suggest that growing density-tolerant cultivars at moderate planting density could serve as a promising approach for stabilizing grain yield and realizing the sustainable development of agriculture in semiarid regions.

Effects of Biochar and Straw Return on Soil Aggregate and Organic Carbon on Purple Soil Dry Slope Land

The aim of the study was to understand the impact of biochar and straw return on soil aggregates and organic carbon for soil improvement of the newly cultivated purple soil dry slope land in the Three Gorges Reservoir area. In this study, a field test was used to set five treatment pairs with regards to soil aggregate composition and organic carbon distribution:no fertilization(CK), conventional fertilization(NPK), optimized fertilization(GNPK), chemical fertilizer reduction combined with straw(RSD), and chemical fertilizer reduction combined with biochar(BC). The results showed that fertilization can improve the level of soil fertility, especially with the RSD and BC treatments. The soil aggregates of each fertilization treatment were<0.25 mm in size. Compared with the CK, each treatment significantly increased the aggregate content of 0.5-5 mm particles, and the values of MWD, GMD, and R0.25. Further, the treatments significantly reduced the value of D and PAD0.25(P<0.05), and each fertilization treatment significantly increased the soil organic carbon content, of which BC(6.73 g·kg-1) and RSD(5.45 g·kg-1) were significantly better than NPK(5.05 g·kg-1) and GNPK(3.63 g·kg-1). The<0.25 mm aggregates had the highest contribution rate of organic carbon(34.92%-59.49%), while the>5 mm aggregates had the lowest contribution rate of organic carbon(1.55%-6.01%). The BC treatment significantly increased the organic carbon contribution rate of 5-2 mm and 2-1 mm agglomerates(P<0.05), while the contribution rate of NPK, RSD, and GNPK was the most significant for 0.5-0.25 mm(P<0.05). Each fertilization treatment increased the yield of rapeseed and corn, with large inter-annual differences, but the overall difference between treatments was not significant. The stability of soil aggregates and crop yields showed an upward trend with the increase of soil organic carbon. Biochar and straw returning to the field may promote the formation of large and medium aggregates in soil, effectively improve the stability of aggregates, increase organic carbon content, and promote crop yields. It is therefore an effective measure to improve the soil structure of purple soil and improve soil quality.

Evaluating agronomic factors for maize production in a semi‐arid Loess Plateau

AbstractCrop production is often affected by multiple agronomic factors. However, little has been reported on the synergistic effects of multiple factors on crop production. Here, we reported the effects of five factors (i.e., variety, planting density, nitrogen application, supplemental irrigation, and plastic mulching) on crop yields, using data from a 5‐yr experiment at Dongyang, Shanxi province of China. An incomplete factorial design with these factors comprised 12 treatments, including two controls: optimized technology (OT) and conventional technology (CT), comprising all five factors applied at the added or subtracted level, respectively. The result showed that, on 5‐yr average, OT significantly increased maize yield by 3.5 Mg ha–1 (44.3% more) as compared to CT (7.9 Mg ha–1), showing a huge potential for increasing yields. Among the five factors, plastic mulching contributed the most in yield increase (11.5%), and high density, improved variety, and irrigation contributed 9.9, 6.9, and 5.1% increases in yield, respectively. There were no significant differences in yield between two N input levels (i.e., 225 and 300 kg N ha–1), suggesting the N input of 225 kg N ha–1 was sufficient to realize a yield level of 8–11 Mg ha–1 in the studied area. In conclusion, reducing the yield gap can only be achieved by optimizing multiple factors simultaneously because the effects of single measure are relatively small and inconsistent among years. The results of our study will help develop adaptive management practices for increasing crop yield stability in other semi‐arid regions.

Designed breeding for adaptation of crops to environmental abiotic stresses

As sessile organisms, crops must deal with and adapt to environmental abiotic stresses such as drought, salinity and extreme temperature during the growth and development for achieving better fitness. With the rapid development of molecular genetics, numerous key genes and extraordinary haplotypes involved in responding and adapting to abiotic stresses have been revealed and characterized, and the underlying molecular mechanisms of their function have also been deciphered. Moreover, a multi-level complex molecular network has been gradually formed to comprehensively understand how plants adapt and confer the tolerance to abiotic stresses. In particular, China has made seminal progresses with respect to the staple crops responding to drought, salinity and temperature stresses. Here we tentatively summarize these cutting-edge progresses and analyze the potential development trend, the bottlenecks and constraining factors in this research area. We also list out the prospective suggestions for the mid- and long-term development layout to promote the transition to the intelligent breeding based on environmental adaptability, which will be important to ensure the continuous and stable crop yield.

Efficacy and economics evaluation of seed rhizome treatment combined with preplant soil fumigation on ginger soilborne disease, plant growth, and yield promotion.

Ginger (Zingiber officinale Roscoe) is widely planted around the world. Owing to continuous planting, ginger is seriously affected by soilborne fungi, bacteria, and nematodes. Although preplant soil fumigation is an effective prevention strategy of soilborne diseases, individual fumigant and technology could not provide effective control of ginger soilborne disease. In our research, different combinations of soil fumigants and seed rhizome treatments were evaluated by monitoring the soil pathogens population, ginger growth, yield, and estimation of economic benefits. Soil fumigation effectively reduced the population of soilborne pathogens, and chloropicrin had a better control effect on soilborne pathogens than dazomet did. Preplant soil fumigation and seed rhizome treatment not only provide good control of soilborne disease, but also reduced the incidence of plant foliar pest and disease. Average yield increase rate of seed rhizome treatment was 12.0%; the highest yield increase was 24.4%. The average cost of seed rhizome treatment only increased by about 2.86%, but the rate of net revenue increase for the seed rhizome treatment reached up to 19.1%. Seed rhizome treatment is a very cost-effective soilborne disease control technology. In the management of soilborne diseases, the combined application of soil fumigation and seed rhizome treatment can reduce the risk of crops infected by soilborne diseases and ensure high and stable crop yields. © 2021 Society of Chemical Industry.

Allometry and Yield Stability of Cereals.

Crop plants grow, and then, they allocate resources to different structures, including seeds and fruits, which represent yield in most crops. We define the yield stability of a genotype as its ability to reduce the effects of temporal variation in resources and conditions on yield production, and we argue that yield stability can be understood in terms of two processes: (1) crop survival and growth (biomass production): the ability of the crop plants to survive and produce biomass under the range of conditions to which it is exposed and (2) the pattern of allocation of this biomass to yield across this range of conditions. Plant breeders and crop physiologists have focused on (1), but much less attention has been paid to (2). We hypothesize that (2) is primarily the result of reproductive allometry: the quantitative relationship between vegetative and reproductive biomass. Ecological theory and the allometric models we present predict a tradeoff between (a) the ability of a genotype to produce yield over a wide variety of conditions and (b) its ability to produce very high yields under optimal or near-optimal conditions. We reanalyze the data from two recent studies, and the results are consistent with this hypothesis. Yield stability in crops corresponds to bet-hedging in evolutionary ecological theory. It is the most appropriate strategy for smallholder farmers in developing countries, a group that comprises most of the farmers in the world. Researchers and crop breeders need to rethink their objectives if they want to develop optimal varieties for these farmers.

Insect pollination enhances yield stability in two pollinator-dependent crops

One of the most important challenges facing global agriculture is to ensure an adequate, stable food supply while conserving soil, water and biodiversity. The yield stability of pollinator-dependent crops, such as pear and apple, can be negatively affected by variability of the pollination service, which in turn can reduce mean yield. We explored how mean crop yield and yield variability were affected by pollinators and variability in their provision of the pollination service. Over four seasons we conducted a manipulative experiment in six pear and eight apple farms; fruit set (i.e., no. fruits/ no. flowers) was compared between flowers exposed to pollinators and those excluded from pollinators. We also recorded pollinator visitation rate to exposed flowers. We estimated the mean levels and spatial and temporal variability of both pollinator visitation and yield response by calculating the mean values per farm and the spatial (i.e., across trees within farm) and temporal (i.e., across seasons within farm) coefficients of variation (CV) for visitation rate and fruit set. Despite homogeneous irrigation and fertilization, we found strong variability in fruit set in both crops (pear spatial and temporal CV: 0.57 and 0.4, respectively; apple: 0.62 and 0.52). Pollinator exclusion reduced mean fruit set considerably in both crops (pears: a reduction of 50%, apples: 71–92%), and increased spatial and temporal variability (pears: 296% and 197% for spatial and temporal variability, respectively; apples: 385% and 329%). Visitation rates in pears were positively associated with mean fruit set and negatively related to its spatial CV. Also, in this crop we found a positive relation between the spatial CV of visitation rate and fruit set. However, there was no evidence that visitation rate in open-pollinated apple flowers affected either mean fruit set or its spatial or temporal variability. Apple trees received one order of magnitude more visits per flower than pear trees, suggesting that in this system the pollination service meets the pollination demand of the apple crop. Overall, our results highlight the importance of management practices that prioritize pollination service, thus ensuring a high, stable yield.

Long-term effects of crop rotation, tillage, and fertilizer nitrogen on soil health indicators and crop productivity in a temperate climate

Although diversifying crop rotations with perennials and cover crops and implementing no-tillage practices has been promoted as an effective strategy for increasing soil carbon and nitrogen storage in the long-term, uncertainty still remains, particularly regarding the association between crop productivity and soil health. Therefore, using two long-term experiments, we investigated the effects of crop rotation, tillage system, and nitrogen fertilizer application (at Ridgetown only) on surface soil (0−15 cm depth) parameters (soil organic carbon (SOC), total nitrogen (TN), commercial soil health tests (evolved CO2 and NH3 indicating microbial activity)), and crop yield in 2016. We used 5-yr average crop yield variability to test for the relationship of SOC and TN with crop yield stability. Results indicated that diversification of corn and soybean rotations and their monocultures with cover crops, perennials, and small grain cereals enhanced soil health indicators (by 32% at Ridgetown (21 yr) and 49% at Elora (36 yr)) and crop productivity (16% at Ridgetown and 29% at Elora). At Ridgetown, corn yield was 10.4% greater with including red clover to the corn-soybean-winter wheat than monoculture corn. Similarly, corn yield was enhanced by 25% when alfalfa was added to monoculture corn at Elora. Nitrogen fertilizer application did not increase surface SOC storage at Ridgetown. No-tillage system had greater evolved NH3-N (by 7.2%) and evolved CO2-C (by 27.9%) than conventional tillage at Elora only. Consistent with management effects on crop yield, at both sites, evolved NH3-N and CO2-C were greatest from rotations with winter wheat, red clover, and alfalfa. Additionally, a strong positive relationship of SOC and TN with soil health tests confirms the suitability of the commercial tests to detect management effects on soil health indicators in the long-term. At both sites, SOC positively correlated with crop yield indicating a direct association between soil carbon status and agroecosystem resiliency. We conclude that diversifying crop rotations increases soil microbial activity, surface SOC sequestration, and crop productivity in the long-term; thus, is a critical component for developing sustainable agroecosystems.

Influence of previous crops on the productivity of winter wheat varieties

In order to realize the maximum potential parameters of winter wheat productivity, it is necessary, first of all, to use high-yielding varieties with optimal quality indicators of grain, as well as progressive agricultural technologies aimed at obtaining a stable crop yield. Winter wheat places high demands on its previous crops. Insufficient amount of productive moisture in the soil or its extremely low reserves affects the yield, and consequently, the quality of winter wheat grain according to unpaired predecessors. Moreover, dry autumn during the sowing period leads to its delay, which is the reason for obtaining uneven and weak seedlings. In this regard, studies have been carried out to study and assess the influence of predecessors on the agrocenosis, yield and grain quality of promising varieties of Adel, Grom, Tanya winter wheat. According to the experimental scheme, peas, corn for silage and sunflower have been identified as the preceding crops for winter wheat. Agrotechnology in experience is generally accepted for the foothill zone of the Republic of Adygea. The results of the research made it possible to identify the most optimal of the considered predecessors in the cultivation of winter wheat, capable of providing stable yields with high quality grain. Certain differences in the photosynthetic activity of the studied winter wheat varieties for different predecessors have been noted. It has been found that the leaf area of winter wheat varieties is in the range of 30,0–33,5 thousand m2/ha. The highest dry matter content in the range of 4,9–5,0 t/ha is observed in the Grom variety, and the predecessor is peas. The largest number of grains in an ear for three previous crops is 40–43 pcs / ear for peas. It also had a fairly significant effect on the weight of 1000 grains and the grain yield of winter wheat. For example, the weight of 1000 grains of the most productive Thunder variety varied from 40,1 to 41,6 gm, depending on the previous crop. According to the results of the experiments, the highest grain yield of winter wheat within the range of 5,3 t/ha has been noted for the Grom variety when cultivated for peas. The smallest grain yield in the range of 3,8–3,9 t/ha is typical for all studied varieties of winter wheat, namely, according to the cultivated predecessor – sunflower.