Evaluating the potential nitrogen savings without yield loss using variable nitrogen application strategies in a heterogeneous winter wheat field

During a single growth season, a plot trial was carried out in a selected heterogeneous field in Denmark in an attempt to estimate the optimal variable nitrogen rate applied to winter wheat. 61 Nitrogen/grain yield dose–response curves were estimated using five nitrogen application rates (30, 90, 120, 180, and 240 kg N ha⁻¹). Provided the dose–response curves were given in advance, enabling optimal nitrogen redistribution, the resulting gain in grain yield would have been less than 0.3 t ha⁻¹. However, from an environmental point of view the data showed that significant nitrogen reductions could be obtained without significant yield loss applying a variable nitrogen application strategy compared to a uniform application.

 

Keywords: variable nitrogen application; optimal nitrogen rate; dose response curve