Submitted to: Crop Management
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/25/2009
Publication Date: 12/3/2009
Citation: Bellaloui, N., Hanks, J.E., Fisher, D.K., Mengistu, A. 2009. Soybean seed composition is influenced by with-in field variability in soil nutrients. Crop Management. doi:10.1094/CM-2009-1203-01-RS. Interpretive Summary: Soybean and corn are major crops grown in the United States. High levels of oil and protein in soybean seed and corn grain are important to growers, seed companies, and food processors. Protein and oil concentrations vary depending on the production system used. The corn-soybean rotation is a well known production system but, its beneficial effect on oil and protein is not understood. Although protein percentage in soybean seed was higher under continuous soybean than in the corn-soybean rotation, yield of soybean was greater in the rotation. Further, low protein percentage resulted from low concentrations of minerals, carbon, and nitrogen in soil. Lower protein and higher starch in corn grain were accompanied with lower concentrations of carbon, nitrogen, phosphorus, potassium, and boron in soil. We conclude that crop rotation and nutrient level in the soil affect seed quality in soybean and corn, and seed composition is reduced under low nutrients levels in soil. Soybean growers can use this information on the beneficial effects of crop rotation and nutrient maintenance in soil to optimize yield and seed composition.
Technical Abstract: Little is known about the beneficial effects of a corn-soybean rotation on seed composition in the Early Soybean Production System (ESPS) in the Midsouth U.S.A. The objective of this study was to investigate the effects of a corn-soybean rotation and the nutrient status of the soil on yield, oil, protein, fatty acids, and mineral concentrations in soybean seed, and protein, oil, starch, and mineral concentrations in corn grain. Soybean (Glycine max (L) Merr.) and corn (Zea mays L.) were grown in three crop rotation sequences beginning in 2002. Results showed that soybean yields were highest under a corn-soybean rotation (CS) and lowest under a corn-corn-soybean rotation (CCS). In corn, however, yields were highest under a CCS rotation. Protein and linoleic fatty acid percentages in soybean seed were higher under continuous soybean rotation (SS). Low protein and linoleic fatty acid percentages resulted from low concentrations of minerals, carbon (C), and nitrogen (N) in soil. Lower-yielding areas of corn showed lower protein and higher starch in grain and lower concentrations of C, N, and phosphorus (P), potassium (K), and boron (B). Results suggest that crop rotation and nutrient level in the soil not only affect yield in soybean and corn but also seed composition. Soil fertility assessments based only on a traditional grid soil sampling may not optimize yield and seed quality. The increase of protein and linoleic fatty acid under SS is significant as it impacts seed quality.