Effects of cultivation and nitrification inhibitor on soil nitrogen availability after a grass ley and on the response of the following cereal crop to fertilizer nitrogen

Abstract

SUMMARY Three experiments carried out at Bridget's Experimental Husbandry Farm, Hampshire between 1984 and 1987 on clay loam and silty clay loam soils over chalk investigated the response of winter wheat grown after grass to spring-applied fertilizer nitrogen. The influence of method of establishment and the use of a nitrification inhibitor were also studied. Yields were similar whether the crops were established by direct drilling or following ploughing. Crops required between 88 and 209 kg N/ha nitrogen fertilizer for optimum yield. There was no consistent difference in nitrogen requirement nor were there consistent differences in nitrogen offtake (which is the amount of N in kg/ha removed in harvested grain) or apparent fertilizer recovery following ploughing or direct drilling. The use of a nitrification inhibitor increased grain yield when applied in the autumn without fertilizer, but not when applied with fertilizer in the spring.