Soybean Biomass and Nitrogen Accumulation Rates and Radiation Use Efficiency in a Maximum Yield Environment

Soybean [Glycine max (L.) Merr.] physiological characterization in a maximum yield environment may identify yield-optimization factors, lead to reassessment of fundamental crop model parameters, and provide guidance for management or breeding efforts. From 2011 to 2013, we characterized biomass and N accumulation rates, radiation use efficiency (RUE), and yield for four or five cultivars in a maximumyield contest field. Grain yield among cultivars ranged from 5290 to 7953 kg ha(-1). The highest yields were observed in 2013, when biomass and N accumulation rates ranged from 45.6 to 64.3 g m(-2) d(-1) and 1.43 to 2.08 g N m(-2) d(-1), respectively, and when RUE values ranged from 1.46 to 1.89 g MJ(-1). The observed crop growth characteristics in 2013 were near or above the maximum values previously reported in the literature. These empirical measurements provide collateral data documenting a soybean crop with grain yields approximately 6719 kg ha(-1).