Yield-Limiting Factors in North Dakota Soybean Fields

Abstract

Average soybean [Glycine max (L.) Merrill] yields in North Dakota remain below north central USA averages, and crop yield potentials. The effect of planting date (PD), cultivar relative maturity (RM), and seeding rate (SR), on yield, were evaluated in 821 producer fields in 2014-2016 seasons. Crop management varied by location. State average PD was 19 May, and planting after 1 May reduced yield average 0.4% d-1. Planting a cultivar with 0.1 RM earlier than recommended reduced yield by 1.3%. Producers estimated seedling mortality at 10%; when observed, it was 12.3%. An additional 7.9% reduction of established population occurred in-season. In-season plant reductions of 4.5% were also observed in research trials. North Dakota producers should plant closer to 1 May if conditions are favorable, select latest-maturing cultivars adapted for area, maximize established plant population relative to seeding rate, and determine causes of in-season plant reductions to adapt management practices if necessary.