中文摘要：

【目的】施肥不平衡是影响砂田西瓜产量和品质的主要因子。研究氮、磷、钾不同施肥量和配施比例对砂田西瓜产量和品质的影响,探明旱砂田西瓜高产、优质的适宜氮、磷、钾施用量和配比,对提高砂田西瓜的生产效率具有重要的现实意义。【方法】本研究以中晚熟西瓜品种陇抗九号为试材,在砂田西瓜全膜覆盖栽培条件下,采用氮、磷、钾三因素的＂311-B＂D饱和最优设计,进行田间微区试验。对西瓜产量和品质结果进行二次回归拟合,建立养分回归数学模型。【结果】因素效应分析结果表明,不同因素对西瓜产量的影响以磷肥最大,氮肥次之,钾肥较小;对西瓜品质的影响以磷肥最大,钾肥次之,氮肥较小,表明在砂田碱性土壤中,磷是影响西瓜产量、品质的首要因素,当氮、磷、钾肥用量分别达231.61、204.34、191.78 kg/hm^2时,边际产量效应值降至0。氮磷、氮钾、磷钾的交互作用对西瓜的产量也有显著影响,某一单一肥料施用量偏高或偏低均不利于西瓜产量的形成,而由于肥料间的交互作用,两者配施则对产量的提高有较强的促进作用。对氮而言,磷的交互效应大于钾;对磷而言,氮的交互效应大于钾;对钾而言,磷的交互效应大于氮,其交互作用最显著的区域为N 115.0 341.8 kg/hm^2、P2O586.5298.2 kg/hm^2、K2O 101.6 298.4 kg/hm^2。利用模型进行决策表明,砂田西瓜产量超过50 t/hm^2的施肥方案为N193.19 238.18 kg/hm^2、P2O5162.41 206.72 kg/hm^2、K2O 164.85 214.53 kg/hm^2;西瓜品质综合评分在85分以上的施肥方案为N 195.96 239.44 kg/hm^2、P2O5167.86 207.52 kg/hm^2、K2O 212.87 267.62 kg/hm^2。【结论】砂田西瓜产量达50 t/hm^2、品质综合评分达85分以上的施肥方案为N 195.96 238.18 kg/hm^2、P2O5167.86 206.72 kg/hm^2、K2O 212.87 214.53 kg/hm^2,适宜的N、P2O5、K2O施用比例约为1∶0.86∶0.98。

英文摘要：

【Objectives】Unbalanced fertilization is a limiting factor to yield and quality of watermelon in gravelmulched fields. So it has important practical significance that studying effect of fertilization on the yield and quality of watermelon,verifying the optimum nitrogen,phosphorus and potassium application rates for higher yield and quality of watermelon and improving production efficiency of gravel-mulched fields. 【Methods】A late mature watermelon cultivar ‘Longkang 9＇was used as material,and micro-spot trials were carried out in gravel-mulched fields under condition of full plastic film mulching by ＂311- B ＂D-saturation optimum design of three factors.【Results】According to the data obtained,mathematical regression models were set up based on the yield andquality respectively by quadratic regression analysis,in which N,P and K were independent variables and the watermelon yield and quality parameters were dependent variables. The model analysis shows that N,P and K significantly influence the watermelon yield and quality parameters,the influenced order of different factors on the watermelon yield is P N K and on the watermelon quality is P K N,which indicates that P is the primary factor to the yield and quality of watermelon in gravel-mulched fields. When N,P and K reach to 231. 61,204. 34 and 191. 78 kg / hm^2,the marginal yield is 0. When single fertilization is high or low,it is not conducive to the formation of watermelon production,and due to the interaction effect,the combined application of N,P and K has a stronger role in promoting of the yield. The interaction effects among these factors are positive on the watermelon yield with the influenced order as N and P P and K N and K,with the biggest interaction area being N at115. 0-341. 8 kg / hm^2,P2O5 at 86. 5-298. 2 kg / hm^2 and K2O at 101. 6-298. 4 kg / hm^2. The model was used to make decision,the fertilization scheme of yield of 50 t / hm^2 is N at 193. 19- 238. 18 kg / hm^2,P2O5 at 162. 41-206. 72 kg / hm^2 and K2O at 164. 85-214. 5