Agronomic Optimal Plant Density by Yield Environment in Soybean

This research report presents a summary of a peer-reviewed publication: Carciochi W.D.; Schwalbert R.; Andrade F.H.; Corassa G.M.; Carter P.; Gaspar A.P.; Schmidt J.; Ciampitti I.A. 2019. Soybean seed yield response to plant density by yield environment in North America. Agronomy Journal. Recent economic and productive circumstances have caused interest in within-field variation of the agronomic optimal plant density (AOPD) for soybean [Glycine max (L.) Merr.]. Thus, the objective of this study was to determine the AOPD by yield environment (YE) for soybean. During 2013 and 2014, nine site-years with a total of 78 yield-to-plant density responses were evaluated in different regions of the United States and Canada. A soybean database evaluating seeding rates ranging from 69,000–271,000 seeds/a was utilized, including the final number of plants and seed yield. The data were classified in YEs: low (LYE, \u3c59.6 bu/a), medium (MYE, 59.6-64.1 bu/a), and high (HYE, \u3e64.1 bu/a). The main outcomes for this study were: 1) AOPD decreased by 24% from LYE (127,000 plants/a) to HYE (97,000 plants/a); 2) greater AOPD in a LYE was not related to a low plant survival rate; and 3) cumulative precipitation during soybean reproductive growth period was 39% lower in LYE compared with MYE and HYE, possibly reducing its reproductive ability. This study presents the first attempt to investigate the seed yield-to-plant density relationship via understanding final plant establishment and by exploring the influence of weather defining soybean YEs in North America

Nutritional Quality of Soybean Seeds Relative to Canopy Portion

Soybean [Glycine max (L.) Merr.] seed quality (nutritional composition) is affected by genetic × environment × management (G × E × M) interactions. Even at the plant level, where differences might not be largely apparent, seed quality is known to change. This study aims to 1) compare seed yield and nutritional quality within the vertical profile of soybean plant canopy, and 2) explore potential interactions for different geno­types. A field experiment was conducted in Manhattan, KS, during the 2018 growing season. Treatments were composed by six genotypes and evaluated at four canopy portions: upper, middle, and lower sections of the main stem and branches. The study was set in a complete randomized block design with three replications. Seed yield and seed size were determined at physiological maturity, as well as seed quality (e.g., protein and oil concentrations). For seed yield, the contribution of the branches was directly affected by the genotype, while the other portions presented a similar yield across genotypes. Seed size was greater in the upper and middle portions of the plant canopy, and seed size of the branches was always comparable to the average of the main stem sections. Overall, oil concentration was lower in branches and did not differ along the sections of the main stem. On the other hand, the protein concentration was greater in the upper portion of the plant. Further research should explore seed quality responsive­ness to the timing of pod-setting and seed-filling within the soybean canopy

Nitrogen and Sulfur Fertilization in Soybean: Impact on Seed Yield and Quality

Over time, plant breeding efforts for improving soybean [Glycine max (L.) Merr.] yield was prioritized and effects on seed nutritional quality were overlooked, decreasing protein concentration. This research aims to explore the effect of nitrogen (N) and sulfur (S) fertilization on soybean seed yield, seed protein and sulfur amino acids concentration. In 2018, ten field trials were conducted across the main US soybean producing region. The treatments were fertilization at 1) planting (NSP); during 2) vegetative growth (NSV); and 3) reproductive growth (NSR) and 4) unfertilized (Control). Nitrogen fertilization was applied at the rate of 40 lb/a utilizing urea ammo­nium nitrate (UAN), and S at 9 lb/a via ammonium sulfate (AMS). A meta-analysis was performed to consider small variations among experimental designs. A summary of the effect sizes did not show effects for seed yield. However, fertilization at planting (NSP) increased seed protein by 1% more than the control across all sites. Overall, sulfur amino acid concentration increased by 1.5% relative to the control, but the most consistent benefit came from fertilization during the reproductive growth (NSR), increasing sulfur amino acids by 1.9%. Although N and S fertilization did not affect seed yields, applying N and S in different stages of the crop growth can increase protein concentration and improve protein composition, providing the opportunity to open new US soybean markets

Planting Date and Maturity Group Interaction for Soybean Productivity and Seed Quality in East Central Kansas

Soybean seed quality is an important component for soybean meal. Different factors affect seed quality, such as genetics, environment, and management (G × E × M). The objectives of this study were to 1) evaluate the effect of planting date and maturity group in soybean seed quality (protein and oil concentrations) and 2) investigate the relationship between soybean seed quality and productivity (seed weight and yield). Three field experiments were conducted during the 2018 growing season evaluating the combination of two factors, planting date and maturity group, with three levels of each one (early, medium, and late). Field measurements included: seed yield, seed weight, and seed quality, mainly represented by determination of seed protein and oil concen­trations. The main outcomes of this study were: 1) early planting date resulted in the highest protein and oil concentrations, while late planting date presented the lowest concentrations for those seed quality components; and 2) protein concentration was negatively correlated with seed yield (r = -0.66)

Nitrogen and Sulfur Fertilization in Soybean: Impact on Seed Yield and Quality

Over time, plant breeding efforts for improving soybean [Glycine max (L.) Merr.] yield was prioritized and effects on seed nutritional quality were overlooked, decreasing protein concentration. This research aims to explore the effect of nitrogen (N) and sulfur (S) fertilization on soybean seed yield, seed protein and sulfur amino acids concentration. In 2018, ten field trials were conducted across the main US soybean producing region. The treatments were fertilization at 1) planting (NSP); during 2) vegetative growth (NSV); and 3) reproductive growth (NSR) and 4) unfertilized (Control). Nitrogen fertilization was applied at the rate of 40 lb/a utilizing urea ammo­nium nitrate (UAN), and S at 9 lb/a via ammonium sulfate (AMS). A meta-analysis was performed to consider small variations among experimental designs. A summary of the effect sizes did not show effects for seed yield. However, fertilization at planting (NSP) increased seed protein by 1% more than the control across all sites. Overall, sulfur amino acid concentration increased by 1.5% relative to the control, but the most consistent benefit came from fertilization during the reproductive growth (NSR), increasing sulfur amino acids by 1.9%. Although N and S fertilization did not affect seed yields, applying N and S in different stages of the crop growth can increase protein concentration and improve protein composition, providing the opportunity to open new US soybean markets

Planting Date and Maturity Group Interaction for Soybean Productivity and Seed Quality in East Central Kansas

Soybean seed quality is an important component for soybean meal. Different factors affect seed quality, such as genetics, environment, and management (G × E × M). The objectives of this study were to 1) evaluate the effect of planting date and maturity group in soybean seed quality (protein and oil concentrations) and 2) investigate the relationship between soybean seed quality and productivity (seed weight and yield). Three field experiments were conducted during the 2018 growing season evaluating the combination of two factors, planting date and maturity group, with three levels of each one (early, medium, and late). Field measurements included: seed yield, seed weight, and seed quality, mainly represented by determination of seed protein and oil concen­trations. The main outcomes of this study were: 1) early planting date resulted in the highest protein and oil concentrations, while late planting date presented the lowest concentrations for those seed quality components; and 2) protein concentration was negatively correlated with seed yield (r = -0.66)

Assessment of nitrogen diagnosis methods in sunflower

Nitrogen deficiency can severely limit sunflower (Helianthus annuus L.) grain yield and quality. Our objective was to evaluate N diagnosis methods based on: (a) pre-plant soil nitrate-nitrogen (NO3––N) test (PPSNT) and soil N mineralized in short-term anaerobic incubation (Nan), (b) Greenness index (GI) and the normalized difference vegetation index (NDVI) measured at 6 (V6) and 12 (V12) leaves, and (c) grain nitrogen concentration (Nc). Seventeen experiments were carried out between 2010 and 2019 in Argentina, evaluating nine N rates (0, 30, 40, 60, 80, 90, 120, 150, and 160 kg N ha–1). The GI, NDVI, N sufficiency index and relative normalized difference vegetation index (NDVIr) were determined at V6 and V12 growth stages. On average, yield response to N was 492 kg ha–1 and Nc response was 0.25% in 9 and 11 responsive experiments, respectively. The inclusion of Nan improved the PPSNT diagnosis method. The critical N availability (PPSNT + fertilizer N) threshold was 115 kg N ha–1 for experiments with low Nan (60 mg kg–1). The NDVIr at V12 allowed monitoring the crop N status with a 0.95 critical threshold. The Nc adequately diagnosed N deficiencies and the critical threshold was 2.26%. Also, Nc was predicted from the ratio between N availability and grain yield (R2 = .39). Our results would allow to better estimate N availability to recommend adequate N fertilizer rates for sunflower aiming to optimize grain yield and quality, and minimize the economic and environmental cost of fertilization.EEA BalcarceFil: Tovar Hernandez, Sergio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Diovisalvi, Natalia. Laboratorio de Suelos Fertilab; Argentina.Fil: Carciochi, Walter Daniel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Carciochi, Walter Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Izquierdo, Natalia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Izquierdo, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Sainz Rozas, Hernán René. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Sainz Rozas, Hernán René. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Sainz Rozas, Hernán René. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: García, Fernando. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Reussi Calvo, Nahuel Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Reussi Calvo, Nahuel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Reussi Calvo, Nahuel Ignacio. Laboratorio de Suelos Fertilab; Argentina