Soybean Production as Affected by Tillage in a Corn and Soybean Management System: I. Cultivar Response

Tillage practices have changed rapidly in the corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] producing areas of the Midwest. The effects of these changes on other crop management decisions must be investigated. Studies were conducted for 3 yr in Minnesota to evaluate the potential interaction between primary tillage systems and soybean cultivars in a corn‐soybean rotation. Eight soybean cultivars were evaluated in no‐till (NT), ridge‐till (RT), fall moldboard plow (MP), fall chisel plow (CP), and Paraplow (PP) tillage systems at Lamberton, Morris, and Waseca, MN from 1986 through 1988. The effect of tillage on emergence varied by year and location. More plants emerged in RT and NT in the dry years of 1987 and 1988 at Waseca, while little difference among tillage systems was noted at Morris during these years, even though weather patterns were similar for the two sites. Yields from MP were lowest at Morris but were among the highest at Lamberton and Waseca. A significant tillage × cultivar interaction for yield occurred at Waseca 2 out of 3 yr and at Lamberton for the 3‐yr average. There did not appear to be any particular genotypic characteristic contributing to this interaction. Soybean cultivar decisions should therefore be based on selecting high‐yielding, disease‐resistant cultivars adapted to a particular geographic area regardless of tillage system.