压砂地西瓜水肥耦合模型及优化组合方案

Model of coupling water with fertilizer in gravel-mulched watermelon field and its optimum combination scheme

采用三因素五水平二次回归通用旋转组合设计方法,在宁夏中部干旱带进行了压砂地西瓜水肥耦合试验,结果表明：在该试验条件下,灌水定额对产量的影响极显著,株距对产量影响较显著,施氮量对产量无显著影响。水氮交互对产量有一定的影响效果,低氮配以高水、中氮配以高水能够达到高产。并且经过水肥耦合模型模拟,得到了实现不同产量目标的最佳水肥组合指标,压砂地西瓜不同产量水平下的因素最优组合方案为：（1）压砂地西瓜产量12000-15000 kg/hm2,补水定额48-61.5 m3/hm2,施氮量24-31.5 kg/hm2,株距1.7-1.9 m;（2）压砂地西瓜产量15000-18000 kg/hm2,补水定额55.5-69 m3/hm2,施氮量24-30 kg/hm2,株距1.4-1.6 m;（3）压砂地西瓜产量18 000-21 000 kg/hm2,补水定额58.5-72 m3/hm2,施氮量24-30 kg/hm2,株距1.2-1.3 m。

Based on the current rotary combination design method of square regression with three factors and five levels,experiment of coupling water with fertilizer in gravel-mulched watermelon field was conducted in central arid region of Ningxia.The results show that irrigation quota is the main factor affecting watermelon yield,and the planting distance was the second factor,while the nitrogen quantity was the third one.Water and nitrogen quantity interaction has certain effect,and it will get high yield when low nitrogen quantity and high irrigation quota are combined,middle nitrogen quantity and high irrigation quota combined.Optimum combination indexes of water and fertilizer on different watermelon yield were gained through the model simulation and experiment.The optimal combination scheme of factors on different yield level of watermelon in gravel-mulched field is：（1） When watermelon yield is 12 000～15 000 kg/hm2,irrigation quota is 48～61.5 m3/hm2,nitrogen quantity is 24～31.5 kg/hm2,and planting distance is 1.7～1.9 m;（2） When watermelon yield is 115 000～18 000 kg/hm2,irrigation quota is 55.5～69 m3/hm2,nitrogen quantity is 24～30 kg/hm2,and planting distance is 1.4～1.6 m;（3） When watermelon yield is 18 000～21 000 kg/hm2,irrigation quota is 58.5～72 m3/hm2,nitrogen quantity is 24～30 kg/hm2,and planting distance is 1.2～1.3 m.All these can provide reference for water-saving irrigation of watermelon in gravel-mulched field in central arid region of Ningxia.