旱砂田补灌水氮互作对西瓜产量、品质及水氮利用的影响

为了探明旱砂田西瓜在有限补灌条件下的最佳水氮耦合形式,采用完全随机裂区设计,研究不同补灌量(W: 0、35、70、105 m³·hm^-2)和施氮量(N: 0、120、200 kg·hm^-2)处理对旱砂田西瓜生长、产量、品质以及水氮利用率的影响.结果表明: 西瓜叶片的光合速率、水分利用效率、产量和氮肥利用率均随着补灌量的增加而增加;西瓜氮肥偏生产力和氮肥利用率均随施氮量的增加而降低;施氮量在0～120 kg·hm^-2时,西瓜叶片的光合速率和品质指标随施氮量的增加而增加,超过120 kg·hm^-2时不再显著增加,甚至有下降趋势;水氮耦合对西瓜产量和水氮利用效率的互作效应显著,其中灌水的增产效应大于氮肥,以W₇₀N₂₀₀和W₁₀₅N_120处理的西瓜产量最高,较对照分别增产42.4%和40.4%,水分利用效率随水氮组合水平的提高而增加,W₇₀和W₁₀₅水平下的所有施氮处理均在26 kg·m^-3以上, W₁₀₅N₁₂₀处理的西瓜氮肥偏生产力和氮肥利用率最高.综合考虑各因素,在本试验条件下,砂田西瓜生育期补灌量105 m³·hm^-2、施氮量120 kg·hm^-2处理为产量和效益兼优的最佳水氮组合.

Interactive impact of water and nitrogen on yield,quality of watermelon and use of water and nitrogen in gravel-mulched field.

In order to develop the optimal coupling model of water and nitrogen of watermelon under limited irrigation in gravel-mulched field, a field experiment with split-plot design was conducted to study the effects of supplementary irrigation volume, nitrogen fertilization, and their interactions on the growth, yield, quality and water and nitrogen use efficiency of watermelon with 4 supplementary irrigation levels (W: 0, 35, 70, and 105 m³·hm^-2 ) in main plots and 3 nitrogen fertilization levels (N: 0, 120, and 200 kg N·hm^-2) in sub plots. The results showed that the photosynthetic rate, yield, and water and nitrogen use efficiency of watermelon increased with the increasing supplementary irrigation, but the nitrogen partial productivity and nitrogen use efficiency decreased with increasing nitrogen fertilization level. The photosynthetic rate and quality indicators increased with increasing nitrogen fertilization level as the nitrogen rate changed from 0 to 120 kg N·hm^-2, but no further significant increase as the nitrogen rate exceeded 120 kg·hm^-2. The interactive effects between water and nitrogen was significant for yield and water and nitrogen use efficiency of watermelon, supplementary irrigation volume was a key factor for the increase yield compared with the nitrogen fertilizer, and the yield reached the highest for the W₇₀N₂₀₀ and W₁₀₅ N₁₂₀ treatments, for which the yield increased by 42.4% and 40.4% compared to CK. Water use efficiency (WUE) was improved by supplementary irrigation and nitrogen rate, the WUE of all nitrogen fertilizer treatments were more than 26 kg·m^-3 under supplemental irrigation levels 70 m³·hm^-2 and 105 m³·hm^-2. The nitrogen partial productivity and nitrogen use efficiency reached the highest in the treatment of W₁₀₅N₁₂₀. It was considered that under the experimental condition, 105 m³·hm^-2 of supplementary irrigation plus 120 kg·hm^-2 of nitrogen fertilization was the optimal combination of obtaining the high yield and high efficiency.