Effects of balanced fertilization on potato yield and quality in Qinghai province

A “3414”field trail was carried out to investigate effects of balanced fertilization on potato yield and quality in Qinghai province. The result showed that equation of fertilizer to potato yield was y =31758.37+6.476N+208.06P-98.82K-2.658NP-2.78PK+0.77NK+0.085N2 +6.413P2 +0.82K2, F =1.432, fertilization recommendation was N 113.9 kg/hm2、袁P2O5 60.9 kg/hm2、K2O 90.3 kg/hm2. Different N, P, K fertilization rates improved potato quality including reducing sugar and starch in different degree. Reducing sugar content was 0.186% in N3P2K3 treatment, which decreased by 9.7% compared with control treatment, it decreased respectively by 9.2%,9.2%,8.3% in N3P2K2,N2P1K1,N2P2K1 treatments compared with control treatment. The starch content was 20.14%,19.67% in N0P2K2,N2P1K2 treatments, which were higher 13.1%,10.4% than in the control treatment. It indicates that high N-medium P-high K fertilization can improve potato reducing sugar quality and low N-medium P-medium K fertilization can improve starch qualith.