Tillage effects on soybean growth, development, and yield

Abstract

Cultivar selection is a crucial component to maximizing soybean [Glycine max (L.) Merr.] yield. Little research exists on the relationship between cultivars and tillage practices in Iowa. Two experiments were established to address this relationship using conventional tillage and no-tillage systems. The first experiment evaluated twelve soybean cultivars at six locations across Iowa from 2007 to 2009 to determine the effect of cultivar performance in two tillage systems. The second experiment was conducted at two locations in Iowa during 2008 and 2009, and examined growth and development of four soybean cultivars in two tillage systems biweekly throughout each season. Few interactions were observed in both experiments. In the first experiment, no interaction was observed between tillage system and cultivar, indicating that a high yielding cultivar is high yielding regardless of tillage system. No yield differences were observed between tillage systems. Plants in the tilled system were 3 cm taller than in the no-tillage system at harvest. Yield differences existed among soybean cultivars, ranging from 4254 to 4930 kg ha. Cultivars resistant to soybean cyst nematode (SCN; Heterodera glycines Ichinohe) yielded 108 kg ha less than cultivars susceptible to SCN. No differences were observed in yield components between tillage systems or cultivars. Based on both experiments, it was concluded that no differences exist between soybean grown in conventional tillage and no-tillage systems in Iowa and that local adapted cultivars can be selected to maximize yield regardless of tillage system in Iowa. Abbreviations: SCN, soybean cyst nematode.