U.S. Soybean Response to High Input Management Systems: Yeild and Quality.

Current soybean prices and limited yield gains in soybean have driven farmers to begin looking for alternative management practices to increase yield. The high commodity prices have provided growers with the means to apply multiple external inputs in an attempt to increase seed yield, but little evidence supports the potential for yield gains from external inputs. The objective of this study was to analyze the potential yield effects and synergistic interactions crop inputs may have on soybean yield and quality. To accomplish our objectives a six state (MN, IA, MI, KY, AR, and LA) collaborative project was conducted from 2009-2011. The selected inputs included additional soil fertility, seed treatment, seed-applied inoculant, foliar fertilizer, foliar fungicide, and two row spacing treatments (76 and ≤ 50.8 cm). Products were applied at recommended label rates and growth stages. A recommended seeding density of 345,800 live seeds ha^-1 was planted, while two of the 14 treatments received an additional 247,000 live seeds ha^-1. An omission treatment structure was implemented to measure crop response to the selected crop inputs, including a control. The treatment receiving all five inputs was considered the high input system (HIS). Other treatments had a single product omitted from the system. In addition, two treatments focused on either early- or late-season management strategies. No difference was observed between HIS planted in wide row spacing and the narrowed control treatment. Seed yield did increase significantly in the HIS and in the late season narrow treatments compared to their respective controls. Seed yield significantly decreased when foliar fungicide was removed from the input system when compared to the HIS; this response was not observed within the other omission treatments. The results indicate that seed yield can be increased with external inputs when planting in narrow row configurations.