Systematic Optimization of Yield-Enhancing Applications: Row Spacing Interactions.

Yield-enhancing products in soybeans have become popular in recent years in response to higher commodity prices.  Little research has been done looking at the combinations of these products with different production practices.  Narrow row spacing along with these yield-enhancing products may be an effective way of maximizing soybean yield. The objective of this study was to evaluate the interaction of aggressive and standard soybean management practices with different row spacings.  Three row spacings: narrow, medium, and wide and four management systems: untreated, fungicide and insecticide seed treatment plus foliar fungicide (ST + Foliar F), “SOYA Complete” (combination of several seed treatments, nitrogen, and numerous foliar products), and “SOYA” minus foliar fungicide were evaluated at five locations (three in Kansas and two in Minnesota) in 2012, 2013, and 2014.  Across all locations in 2012 and 2013, management systems acted similarly across all row spacings.  Averaged across all locations in 2012 and 2013, narrow rows out yielded medium and wide rows by 153 kg ha^-1 and 213 kg ha^-1 respectively.  Averaged across all locations in 2012 and 2013, SOYA Complete and SOYA minus foliar fungicide out yielded ST + Foliar F and untreated systems by 127 kg ha^-1 and 244 kg ha^-1 respectively.  Overall, narrow rows have a tendency to yield higher than wide rows regardless of management system and the aggressive management systems tended to yield higher than the standard management systems regardless of row spacing.  Response to aggressive soybean management practices does not depend on row spacing.