Effects of different proportions of N, P, and K on nitrate contents in rape
氮、磷、钾配合施用对油菜硝酸盐含量的影响

The field and plot experiments were conducted to study the effect on the accumulation of nitrate in rape by applying different kinds of fertilizers and proportions. The results show that nitrogen fertilizer is the main source of the NO3--N in rape. The appropriate combination of N, P. and K fertilizer can significantly reduce the NO3 -N content, and there are big differences in the effect on nitrate by applying different N, P, and K proportions in field and greenhouse conditions. The best amounts of N, P, and K applied in greenhouse is N 225kg/hm2 , P2O5 60kg/hm , and K2O 45kg/km2, and the proportion of N : P2O5: K2O is 5 : 1 . 33 : 1. In this way the guaranteed high yield and low nitrate in rape can be obtained.