Integrated Evaluation of Multiple Inputs to Increase Soybean Yield in Nebraska (Part I): Evaluating Common Management Practices of Soybean Production.

Research into high yielding soybean [Glycine max (L.) Merr.] needs an integrated approach that includes pest management, agronomic practices, and fertility. Utilizing the Soybean Management Field Days program locations, a multi-input study was conducted over two years with four sites each year. The purpose of this research was to determine the additive value of several inputs under a wide range of Nebraska conditions. All sites were irrigated and soil textures were representative of Eastern Nebraska, sites in 2014 had silty clay loam at Auburn and Snyder and silt loam at Fullerton and Shickley. The experiment was a split-plot alpha lattice design with row spacing (38 cm and 76 cm) as the whole plots and a factorial of five seed/early (growth stage V2) treatments (nontreated, fungicide, insecticide and fertility combinations), and six foliar (reproductive stage R3) treatments (nontreated, fungicide, insecticide and fertility combinations) at pod set with four replications at each site. Row spacing at 38 cm yielded higher at all locations with a 317 kg/ha increase in yield (P<0.0001) averaged across three of the four locations. The effects of early and pod set treatments on yield varied by location. At Snyder, the addition of insecticide seed treatment resulted in 202 kg/ha increase in yield from the no treatment (P=0.0001). At Snyder, the addition of pod-set combination treatments of fungicide with fertility or insecticide resulted in 417 kg/ha increase in yield compared to no treatment (P<.0001). Across locations, the addition of pod-set combination treatments of fungicide with fertility or insecticide resulted in 175 kg/ha increase in yield compared to no treatment (P=0.012). In 2014 there were no interactions of early season treatments with pod-set applications of the common production inputs evaluated. Treatments were evaluated with the same design in 2013 and no significant differences due to treatments were observed.