Soybean Agronomic Response to Management Systems in the Upper Midwest

There has been a rapid increase of soybean [Glycine max (L.) Merr.] production in cropping systems in Wisconsin. The objective of this research was to determine the influence of five management systems on agronomic traits for three soybean cultivars grown at two different planting dates. An older cultivar (Hardin) and two newer cultivars (DeKalb CX232 and Spansoy 250) were grown in five management systems between 1997 and 2000. Four management systems were located on a silt loam soil and consisted of conventional and no‐tillage systems with and without irrigation. The fifth management system was located on a sandy loam soil that was irrigated. A planting date × cultivar interaction was observed on the silt loam soil where CX232 yielded 7% greater for the early planting date (4.37 Mg ha−1) than for the late planting date, but no planting date effect was observed for Hardin and Spansoy 250. Over all cultivars, yield was 4% greater for early planting on the silt loam soil. Grain yield and other agronomic traits were not influenced by cultivar and planting date on the sandy loam soil. Tillage and irrigation did not affect grain yield or most of the other agronomic traits. Regression of cultivar means on management system indicated an equal stability for yield among the cultivars tested with Hardin tending to be the most stable. It was concluded that soybean cultivar decisions in the Upper Midwest should be based on selecting the highest yielding cultivars adapted to a particular geographic region and location regardless of management system.