Residual effects of poultry manure and fertiliser nitrogen applications

Abstract

The effect of fertiliser nitrogen (N) and poultry manure N applications to sugar beet and potatoes on residual soil mineral nitrogen (SMN) supply and yield of following cereal crops was studied in four field experiments in 1991 and 1992. In both seasons, fertiliser N applications to sugar beet (range 0–180 kg N ha−1) had no effect on residual SMN supply or yield of the following cereal crops. However, poultry manure applications supplying > 600 kg total N ha−1 increased residual SMN supply and yield of the following cereal crops. Fertiliser N applications to potatoes in 1991 (range 0-300 kg N ha−1) increased residual SMN and yield of the following cereal crop where 300 kg N ha−1 was applied. However, in 1992, no increase in residual SMN or yield of the following cereal crop was recorded. Poultry manure N applications > 800 kg total N ha−1 increased residual SMN supply and > 400 kg total N ha−1 increased following cereal crop yields. These results demonstrate the ability of sugar beet to scavenge soil N and low residual N value of poultry manure applications at agronomically sensible rates.