Research: Key Management Practices That Explain Soybean Yield Gaps

Shawn Conley, Soybean and Wheat Extension Specialist, UW-Madison Department of Agronomy

To date, identification of causes of yield gaps (difference between maximum yield potential and measured yield in producer yields) has been restricted to small geographic areas. In this study, researchers developed a novel approach that combines producer-reported data and a spatial framework to identify explanatory causes of yield gap over large geographic regions with diversity of climate, soils, and water regimes (rainfed and irrigated).

This research focused on soybean in the North-Central United States region, which accounts for approximately one third of global soybean production, as a case study to provide a proof of concept on the proposed approach.

  • We developed a novel approach that combines producer survey data with a biophysical spatial framework for identifying causes of yield gaps over large agricultural areas with diversity in climate and soils.
  • The approach was applied to both rainfed and irrigated soybean in the North Central US region, and it was based on producer survey data on yield and management collected from 3,568 elds over two crop seasons.
  • The analysis indicated that the average regional yield potential was 71 bu ac-1 (rainfed) and 85 bu ac-1 (irrigated), with a respective yield gap of 22% and 13% of maximum yield potential.
  • Planting date, tillage, and in-season foliar fungicide and/or insecticide were identi ed as explanatory causes for yield variation, with planting date the most consistent management factor that in uenced soybean yield.

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