Environmentally Smart Nitrogen (ESN) is a polymer-coated urea fertilizer with potential to increase crop recovery of fertilizer nitrogen (N). Our research objectives were to characterize ESN N retention across time as affected by soil series, temperature, moisture, and incubation method. A rumen bag containing 38 to 44 mg ESN N was placed in 400 g soil, and the amount of ESN N remaining in prills was measured every 5 d for 40 d. Soil was incubated at 25 °C and 250 g H₂O kg⁻¹ soil, except in experiments where soil temperature or moisture was varied. Nitrogen retention in ESN was linear for three silt and sandy loams and curvilinear in two clayey soils with retention declining more rapidly in clayey soils. Soil temperature had the greatest effect on N retention with the rate of ESN N release increasing as soil temperature increased. Near complete release of ESN N was achieved by 40 d with temperatures ≥ 20 °C.

Greenhouse studies were conducted to evaluate the influence of nitrogen (N) sources [urea + ​N-(n-butyl) thiophosphoric triamide, NBPT (urease inhibitor) and polymer-coated urea (PCU)] and rates on soybean root characteristics, nodule formation, and biomass production on two soil types (silt loam and clay) commonly cropped to soybean in Mississippi. About 15% less belowground biomass was produced in clay soil than in silt loam soil directly corresponding to all other root parameters including root length, root area, root diameter, and nodule number. Pooled across N rates, N additions resulted in 19% and 52% decrease in belowground biomass and number of nodules, respectively, across soils compared to soybean receiving no N. The N rate was the most critical factor as it influenced all root growth parameters. Number of nodules were 24% greater with PCU than urea + NBPT. Nitrogen additions and clay soil negatively impacted soybean root growth, nodulation, and belowground biomass production. Abbreviations: Polymer-coated urea, PCU; N-(n-butyl) thiophosphoric triamide, NBPT

This study was conducted to determine if root, shoot, and gas exchange traits of determinate and indeterminate soybean cultivars respond differently to soil water deficit. The effect of soil water deficit imposed 4 and 10 days after sowing on growth and development parameters of determinate and indeterminate soybeans was evaluated for 18 and 30 days in experiment I and II, respectively. At both 18 and 30 days after seeding, nearly all root, shoot, and physiological parameters were inversely correlated with the soil moisture level, and the adverse effects of drought stress were more evident in Progeny P5333RY than in Asgrow AG5332. For both cultivars, the effect of soil water deficit on net photosynthesis was mainly due to stomatal limitations. The developed algorithms for the plant processes based on the environmental productivity index were not different between the cultivars, suggesting that soybean plants respond in a similar way irrespective of their growth habits, probably due to the shorter period of water stress.

Purple seed stain disease, caused by (Cercospora kukuchii), is a major concern in soybean (Glycine max (L.)) in Mississippi, USA, due to its effects on seed quality, reducing soybean seed grade and potential market price at elevators. Therefore, investigating the effects of purple seed stain (PSS) on seed quality (germination and vigor) and seed composition (nutrition) is critical. The objective of this study was to investigate the effects of PSS on seed harvest index, seed germination, seed vigor, and seed composition components (protein, oil, fatty acids, and sugars). A field experiment was initiated in 2019 in Stoneville, MS, at the Delta Research and Extension Center (DREC) on a Commerce silt loam soil (fine-silty, mixed, superactive, nonacid, thermic Fluventic Epiaquepts). Soybean variety Credenz 4748 LL was used. The results showed that infected (symptomatic) seed had a 5.5% greater Seed Index (based on 100 seed weight) when compared to non-infected (non-symptomatic, as control) seed. Non-infected seed had greater percent germination and seedling vigor when compared to infected seed. Germination was 30.9% greater and vigor was 58.3% greater in non-infected seed. Also, the results showed that infected seed with PSS had higher protein content and some amino acids. No changes in total oil and fatty acids. Sucrose and stachyose were lower in infected seed than in non-infected seed. The research showed that PSS impacted seed health and seed quality (germination and vigor) and seed composition (protein, sugars, and some amino acids). Purple stained seed should be avoided when planting and should be managed properly as low germination is a potential risk. Planting population should be adjusted accordingly due to lack of germination and vigor if PSS is present. This research help growers for purple seed management, and scientists to further understand the potential negative impact on seed quality and nutrition. Further research is needed before conclusive recommendations are made.

Zinc deficiency symptoms have been observed on corn (Zea mays L.) grown on coarse‐textured, high‐pH soils in the Mississippi Delta. To correct deficiencies, many corn producers apply foliar Zn. Corn injury from foliar Zn application has been observed; however, it is not clear whether foliar Zn injury affects grain yield. Also, little information currently exists about the ability of foliar Zn sources to increase corn tissue Zn concentration. Therefore, the purpose of this study was to determine the effect of Zn source and Zn application rate on foliar injury, tissue Zn concentration, and grain yield in corn. Zinc‐citrate, Zn–ethylenediaminetetraacetic acid (EDTA), and ZnSO₄ were applied to corn at 0.56, 1.12, and 2.24 kg Zn ha⁻¹ at V4. Corn injury was evaluated 3, 6, and 9 d after application, and tissue Zn concentration was determined 2 wk after Zn application. Grain yield was determined at harvest. Zinc‐citrate imparted the greatest injury at all application rates, followed by ZnSO₄ and Zn‐EDTA. Injury generally increased as Zn application rate increased. The 0.56 kg Zn ha⁻¹ rate resulted in similar tissue Zn content across all Zn sources. Zinc‐citrate and ZnSO₄ application resulted greater tissue Zn content than Zn‐EDTA at 1.12 and 2.24 kg Zn ha⁻¹ rates. Despite high levels of foliar injury observed for some Zn sources and rates, no differences in grain yield were observed. Citrate‐Zn application to corn caused more foliar injury than EDTA‐Zn and Zinc sulfate. Citrate‐Zn resulted in highest corn tissue Zn concentrations. Corn injury from foliar Zn application did not affect grain yield.

Soybean (Glycine max L.) seed is a major source of protein, oil, carbohydrates and other nutrients that are important for human and animal nutrition. Producers have considered applying nitrogen (N) fertilizer to soybean crop to maximize seed yield; however, its effect on seed composition is not well understood. The objective of this two-year (2015 and 2016) study was to evaluate the effects of N fertilizer sources and application rates (45, 90, 135 and 179 kg N ha⁻¹) on soybean seed composition on two soil textures (clay and silt-loam) in Mississippi. The three fertilizer sources included in this study were urea with N-(n butyl) thiophosphoric triamide (Urea+NBPT), polymer-coated urea (PCU), and ammonium sulfate (AMS). Nitrogen application at 179 kg ha⁻¹ on clay soil reduced seed protein by 1.05% compared to unfertilized soybeans in 2016. However, N application at 179 kg ha⁻¹ increased oil content by 0.7% on clay soil compared to the unfertilized soybeans only in 2016. Nitrogen applications reduced stachyose content on both soil textures in 2015. The fatty acids showed variable response to N applications. Since, seed quality is not a trait from which growers receive an economic incentive, they are unlikely to adopt this practice for standard soybean production.