To study the effects of NPK fertilizer and planting density on potato yield, virus-free sweet potato "Longyan 7-3" was cultured with 4 factors ×5 levels quadratic general rotational design. A high yield mathematical model was built by computer simulation to obtain the optimum agronomic measures. The results showed that: (1) the optimal combination of 4 factors for yield over 45.0 t ? hm-2 was: applying urea between 163. 05 - 191. 55 kg ? hm-2 , crude calcium 546. 6 - 653. 4 kg ? hm-2, potassium sulphate 510. 3 - 614. 55 kg ? hm-2, and planting density at 5. 45×104-5. 80 × 104 plants per ha; (2) the effect of 4 factors on potato yield was in order of K> planting density>N>P fertilizer; (3) the interaction effects on the yield were observed among the factors; (4) increase of K and N fertilizers were conducive to the yield enhancement of Longyan 7-3; and (5) the suitable planting density resulted the high proportion of large and medium size tuber.u0000nterac%以脱毒甘薯龙岩7-3为材料,采用四因素五水平二次通用旋转组合设计,探讨氮、磷、钾肥不同施用量和种植密度对产量的影响.经计算机模拟建立施肥的高产数学模型并找出最佳农艺措施组合方案.结果表明,①产量超过45 t·hm-2的最佳农艺措施组合为尿素施用量163.05～191.55 kg·hm-2；过钙施用量546.6～653.4 kg· hm-2；硫酸钾施用量510.3～614.55 kg·hm-2；种植密度5.45万～5.80万株；②4个因素对鲜薯产量影响的顺序依次为钾肥＞密度＞氮肥＞磷肥；③各因素间对产量影响皆存在一定的互作效应；④较高水平的施钾量和施氮量有利于产量的提高；⑤适宜种植密度条件下大中薯率高.
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