Planting Date and Delayed Harvest Effects on Soybean Seed Composition

Information on crop management practices that may help maximize farm profit is valuable. Because planting date determines the environment to which the crop is exposed during the growing season, it can also have a significant impact on seed composition. In this study, the effects of planting date on seed organic and inorganic composition were investigated using eight specialty soybean [Glycine max (L.) Merr.] breeding lines with modified seed composition (high protein, high oil, high oleic acid, low linolenic acid, low saturated fatty acids, high inorganic phosphorus-low stachyose) grown at two Arkansas locations for 2 yr. The effects of delayed harvest on seed composition were also studied in one of the planting dates. Early planting increased seed protein, oleic acid, and inorganic components and decreased linolenic acid concentrations, whereas late planting increased sucrose but did not affect stachyose concentrations. Production of soybeans with high-protein, high-quality oil should be performed in early-planting production systems, whereas planting high-sugar, food-grade cultivars late in the season should fit well in a double-crop system. Delayed harvest had effects on both organic and inorganic seed components. Seed constituents exhibited lower concentration in soybeans that experienced delayed harvest. These research findings may help enhance recommendations to farmers to adjust planting and harvest practices and consequently meet market requirements for specialty soybeans.