Previous cropping and soil mineral nitrogen as predictors of yield response of winter wheat to nitrogen on silt soils in United Kingdom

Abstract

Abstract. The fertilizer nitrogen requirement of winter wheat was assessed in sixteen experiments on marine silt soils in Eastern England. Eight experimental sites followed potatoes (Solanum tuberosum), six vining peas (Pisum sativum) and two wheat (Triticum aestivum). The yield response to nitrogen fertilizer was much less following peas than potatoes or wheat, five sites following peas showed little response to more than 30 kg N ha–1. Previous crop explained some 79.7% of the variation in nitrogen optima. When autumn soil mineral nitrogen was also taken into account 81.9% of the variation in optimum nitrogen rate was explained (P<0.001). The study revealed noticeably higher levels of autumn soil mineral nitrogen following vining peas on some sites than those found elsewhere in the UK and as assumed in the standard national fertilizer recommendation system.