Analysis of N-P-K fertilizer response mode on potato among rice cultivation area in Changde

To establish potato fertilizer effect model,“3414”field experiments on potato were conducted in winter fallow rice field of Changde. The results showed that total yield was declined under potassium deficiency; tuber yield, commodity potato rate and total yield were significantly declined under nitrogen and phosphorus deficiency. The fertilizer contribution rate was close to 70% at the present land capability. Nitrogen, phosphorus and potassium had the best yield response in the fertilization level 2 and showed hump-backed pattern as fertilizer amount increasing. The positive effects of fertilizer followed as N ＞ P ＞ K. The tuber total nutrients availability was 22.6%. Nitrogen, phosphorus and potassium content of tuber also had the best yield response in the fertilization level 2 and showed hump-backed pattern as fertilizer amount increasing. The positive effects of tuber nutrients availability followed as N ＞ P ＞ K. Data were analyzed based on the“3414”xperiments to establish the ternary quadratic and one-place quadratic fertilizer models. The recommendation of N, P and K was 15.1, 7.6 and 2.2 kg/667 m2 respectively based on R2 and value to cost ratio (VCR). The optimal ratio of N, P, K was 1:0.50:0.15.