Fertilizers response model and optimal fertilizer rates for potato (Solanum tuberosum L.) production in Diqing.

Optimal fertilizer rate based on a fertilizer response model is an important component in the best nutrient management system.Field trials,which consisted of 3-factors(N,P and K) and 5-levels,in an orthogonal rotational combination design,were conducted in Diqing,Yunnan province,to study the effect of different N,P,and K fertilizer rates and ratio on tuber yield in potato,Solanum tuberosum L.production,.The fertilizer response models were established based on the regression equations of N,P,and K fertilization effect on the tuber yield to tested fertilizer rates,from which the optimal fertilization rates were determined.The results indicated that the fertilization rates for the highest yield(34147kg/hm2) were 240kg N/hm2,150kg P2O5/hm2 and 480kg K2O/hm2;the economic optimal yield was 34070kg/hm2 and the optimal fer-tilizer rates for economic yield were 240kg/hm2 N,150kg/hm2 P2O5 and 420kg/hm2 K2O;the optimal fertilizer rates for maximum profit were 60kg/hm2 N,30kg/hm2 P2O5 and 120kg/hm2 K2O.