M.S. Exit Seminar - Grace Bluck
M.S. Exit Seminar
Dr. Laura Lindsey, advisor
March 12, 2015 at 2:10 PM in Kottman 244 (Columbus) and videolink to 121 Fisher (Wooster)
Title: Soybean Yield Response in High and Low Input Production Systems
Abstract: Since 2000, soybean [Glycine max (L.) Merr] grain commodity price has increased by almost 300% generating interest in agricultural inputs to maximize soybean yield. The objective of this study was to evaluate the effect of common inputs on soybean grain yield in enhanced (high-input) and traditional (low-input) production systems. The inputs evaluated included: Rhizobia inoculant, gypsum, pyraclostrobin fungicide, lambda-cyhalothrin insecticide, and manganese (Mn) foliar fertilizer. A sixteen site-year trial was established in Ohio during 2013 and 2014. Rhizobia inoculant was seed applied before planting, gypsum was applied at the VC growth stage (unrolled unifoliate leaves), and fungicide, insecticide, and Mn foliar fertilizer were applied at the R3 growth stage (initial pod development). Measurements of percent leaf area affected by foliar disease and insect defoliation and Mn and sulfur (S) concentration in leaves were collected at six site-years. The omission of pyraclostrobin from the enhanced production system significantly reduced yield in five of sixteen site-years by 0.21 to 0.79 Mg ha-1, but its addition to a traditional system increased yield significantly at only one of sixteen site-years by 0.47 Mg ha-1. Fields with high disease and above average yield (>3.5 Mg ha-1) that received over 25 cm of precipitation in June and July tended to be responsive to the fungicide application. During 2013 and 2014, with established corn/soybean rotations, no S or Mn deficiencies, and minimal insect pressure, there were limited effects of inoculant, gypsum, insecticide, and Mn foliar fertilizer on grain yield. Knowledge of potential yield limiting factors is useful in identifying inputs that will increase soybean yield on a field by field basis.