Producers choosing to implement an early corn planting management strategy often experience several yield limiting biotic and abiotic factors. Field variability, flooding, sub-optimal soil temperatures which leads to poor nutrient uptake, delayed emergence and reduced root growth can limit grain production. Three separate experiments were conducted to address some of the negative effects associated with early corn planting. Experiment 1 evaluated flooding effects on several morpho-physiological traits including root system architecture during early crop development. Hybrids (DKC 6208, Pioneer 1197) were flooded at planting (V0) and growth stages V1, V2, V3 for 0, 6, 12, 24, 48, 96 hours. Plants flooded at V0 11% suffered the steepest decline in collar height. Plants flooded at V2 10% were more susceptible than plants flooded V1 4%. Overall, there was a linear decline in nutrient concentration if flooding occurred at planting. Tissue Na levels were the most affected by flood duration and K was the least affected. Experiment 2 evaluated biologic compounds developed to increase immobile nutrients P and K to improve fertilizer use efficiency and provide slow developing roots essential nutrients. The effectiveness of microbial products (B-300, QR, Mammoth, EM-1) with/without starter fertilizer influenced yield, emergence, plant growth, and nutrient uptake. Biologic seed treatments compared to the control, resulted in a positive yield advantage for all treatments. Yields ranged from 37 to 48% higher if biologic compounds were applied. On average, yields increased from 26 to 38% after starter fertilizer was added to the biologic compounds. Phosphorus levels at VT were significantly higher for QR and K content was higher for B300, SF-B300, QR, Mamm, and SF-Mamm compared to the control. Experiment 3 addressed soil physical/chemical properties affecting plant development and there yield plant density relationship. On average, yields significantly increased 40% as plant population increased from 49,400 to 103,740 plants ha−1. Based on the quadratic model agronomically yields would be highest at 61,360 plants ha−1. Correlation analysis among yield and soil physical and chemical properties revealed positive correlations for grain yield, sand% (r2 = 0.42), soil K (r2 = 0.17) soil Na (r2 = 0.46), and soil P (r2 = 0.49).

Edamame's (Glycine max L. Merrill) consumption in the US has also been growing due to purported health benefits. Edamame grows well around the US, but few have measured the growth and yield in the mid-Atlantic region. The objective of these studies were to determine the potential yield of edamame, determine how yield components change with planting date and cultivar, and to measure total protein, lipids, antioxidant activity and isoflavone concentrations at harvest.. The five cultivars (BeSweet 292, BeSweet 2015, BeSweet 2001, Midori Giant and Sunrise) used in the cultivar evaluation trial and for nutritional constituents analysis were grown in Painter, Virginia in 2008 and 2009. The cultivar evaluation trial yielded between 5,600 and 8,400 kg per ha. Percent marketable pods ranged from 74.3 and 85.6% in the cultivar evaluation trial. There were significant differences in average seed size across cultivars in both years. Cultivar lipid content followed the same patterns in both years with 2009 having lower overall concentrations than 2008. Protein contents were similar in 2008 and 2009. Both years, "BeSweet 2015" and "BeSweet 2001" had high radical scavenging ability and Midori Giant had the lowest. In 2008, there were no significant differences in the ORAC assay. "BeSweet 292" had significantly more reducing activity in the DPPH assay than Sunrise in 2009. Isoflavones were measured in 2008 and 2009 at harvest and temporally in 2009. Of all isoflavones, Malonyl genistin had the highest concentration. Edamame is a suitable crop for cultivation in Virginia, and is high in nutritional quality. / Master of Science

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