滴头流量对压砂土壤水盐分布及西瓜生长、产量的影响

Abstract

【目的】探明微咸水灌溉条件下滴头流量对压砂地土壤水盐分布及西瓜生长和产量的影响。【方法】通过田间试验，设置Q1（2 L/h）、Q2（3 L/h）、Q3（4 L/h）3种滴头流量，研究滴头流量对灌水前后土壤水盐分布特征、西瓜生长、产量、果实品质及水分利用效率的影响。【结果】滴头流量越大，土壤水平湿润范围越大，膜间土壤含水率越高，滴头下方垂直湿润深度越浅。各处理0~100 cm土壤盐分经过一个全生育期均呈下降趋势，盐分减少量随滴头流量增大而增加。果实可溶性糖量随滴头流量增大呈先增大后减小趋势，Q2处理最大，分别较Q1、Q3处理提高了54.3%和22.3%；维生素C量随滴头流量增加呈先减少后增加趋势，Q3处理最高，较Q2处理提高了53.7%。西瓜产量与灌溉水利用效率均随滴头流量增大而增加，Q3处理产量分别较Q1、Q2处理提高了6.20%和3.56%，Q3处理的灌溉水利用效率分别较Q1、Q2处理提高了6.49%和3.72%。【结论】综合考虑土壤水盐再分布形式与西瓜产量、品质，适用于压砂地西瓜微咸水滴灌流量为Q3（4 L/h）。

Alternate abstract:

【Objective】Gravel mulching combined with drip irrigation is an improved agronomic technique for crop production in northwestern China. The purpose of this study is to investigate the impact of dripping rate of the emitters on soil water and salt redistribution, as well as the growth and yield of watermelon.【Method】The field experiment had three treatments with the dripping rate controlled at 2 L/h (Q1), 3 L/h (Q2), or 4 L/h (Q3), respectively. In each treatment, we measured the spatiotemporal variation in soil water and salt, water use efficiency, as well as growth, yield and fruit quality of the watermelon.【Result】Horizontal advancement of the wetting front in the soil increased with dripping rate. After harvest, soil salt content in the 0~100 cm soil layer decreased, with the decreasing rate increasing as the dripping rate increased. Also, with the increase in dripping rate, the soluble sugar content in the fruits increased first followed by a decline. Of the three dripping rates we compared, Q2 increased the soluble sugar content in the fruit the most, up by 54.3% and 22.3%, respectively, compared to Q1 and Q3. With the increase in dripping rate, the vitamin C content in the fruits decreased first and then ramped up. Q3 gave the highest vitamin C content, increasing by 53.7% compared to Q2. Increasing dripping rate boosted both fruit yield and water use efficiency. Compared to Q1 and Q2, Q3 increased fruit yield by 6.20% and 3.56%, and water use efficiency by 6.49% and 3.72%, respectively.【Conclusion】Taking soil water and salt redistribution, as well as watermelon yield and quality into account, the optimal dripping rate for watermelon growth in the gravel-mulched soil was 4 L/h when using the local saline water for irrigation.