| Though the pot experiment of water and fertilizer coupling for potato by drip irrigation under film, taking the irrigation time (X1), amount of irrigation (X2), quantity of nitrogen (X3), phosphate (X4) and potassium
(X5) were for the test factors. Adopted the design of 5 factors and 5 levels quadratic regression by rotation-orthogonal combination to study the effects of different NPK fertilizer combinations to the yield of potato, has established the equations of potato yield with the irrigation time, quantity of the NPK fertilizer and amount of irrigation. The results indicated that: The function order for each factors was X5＞X4＞X3＞X2＞X1, and the effect sequence for the potato yield by the interaction term as X4X5＞X3X5＞X2X4＞X2X5＞X2X3. When the yield as for the object function, the highest yield was 33.785 t·hm-2, the percentage of irrigation amount at seeding period, budding stage and initial boom stage to the whole irrigation quota was 25%, 25%, 50%, respectively. We suggest that whole irrigation quota was 822 m3·hm-2，the quantity of the N, P and K was 73.5 kg·hm-2, 224.4 kg·hm-2 and 223.8 kg·hm-2, repectively. |