Effects of Combined Application of Nitrogen,Phosphorus and Potassium on Yield and Its Components of Rape

Rape field experiment of fertilization effect was conducted.The results showed that the reasonable combined application of nitrogen,phosphorus and potassium fertilizer could significantly increase the plant height,the first branch number,pod number,seed number per pod and 1000-grain weight,and decrease the first branch height.The utilization of potassium fertilizer could obviously increase the plant height of rape,and it also could play a certain promotive function on other growth indexes,while its effect was lower than the application of nitrogen and phosphorus fertilizer.The yield-increasing rates of applying nitrogen,phosphorus and potassium fertilizer were 77.0%,19.2% and 31.3% respectively.The optimum fertilizer application rate was N 219.4 kg/hm2,P2O5 53.8 kg/hm2,K2O 73.6 kg/hm2,and the highest yield was 2653.7 kg/hm2.The reasonable combined application of nitrogen,phosphorus and potassium fertilizer could not only improve the nutrient content in rape plants,but also enhance the utilization ratio of fertilizer,optimize all growth indexes and get the highest yield of rape.