Economic Analysis of Increased Protein and Decreased Yield Due to Delayed Planting of Soybean

Protein content of soybean [ Glycine max (L.) Merr.) is known to increase as planting date is delayed. A recent decision by the Federal Grain Inspection Service to offer protein and oil testing as official criteria may increase farmer's interest in cultural practices that alter the chemical constituent value of soybean. The objective of this study was to determine if the gross value per acre was increased sufficiently, due to the increased protein of delayed planting date, to economically offset the decreased oil content and grain yield. Three soybean cultivars were evaluated as whole plots in a split‐plot design, in factorial combination with five planting dates and three different sizes of seed planted as split plots. The increased value due to higher protein did not economically compensate for the decreased oil percentage and grain yield from late plantings. Gross value per acre decreased as planting date was delayed for the three protein price to oil price ratios evaluated.