Abstract:

Effect of sowing density and rates of nitrogen、phosphorus and potassium fertilizers on yield of purple potato (cv. ziluolan) were tested by employing quadratic saturation D optimum design method. Regression equations of yield value were established. The optimum agricultural combination factors for the purple potato sowing in the early February in east of Zhejiang province obtaining a yield more than 22.5 kg/hm2, were showed as follows: the sowing density was 55900-58800 plants/ hm2; rates of nitrogen were 141.27-161.79 kg/hm2; rates of phosphorus were 103.68-118.68 kg/hm2; rates of potassium were 242.22～264.72 kg/hm2. The results indicated that the sufficient sowing density in co-operation with nitrogen-controlling, phosphorus-increasing and potassium-sufficient were the effective ways to achieve high yield of purple potato.