灌溉水量和水质对土壤水盐分布及春玉米耗水的影响

【目的】研究灌溉水量和水质对土壤水盐分布和春玉米耗水的影响。【方法】在石羊河中游,通过2007—2008两年的灌溉试验,对供试春玉米采取不同的水量和水质处理,测定土壤含水量和含盐量及玉米生长指标。【结果】灌溉水量对土壤含水量变化的影响在60—100cm土层较为明显,2008年9g·L-1处理和6g·L-1处理20—100cm土层平均含水量保持在25%以上;土壤含盐量随灌溉水矿化度的增大而增大,随灌溉水量的减少而降低;供水不足时,作物耗水量及土壤储水变化主要受水量的影响,供水充足时则主要受灌溉水质的影响;咸水灌溉条件下,一定的水分亏缺同样能够提高水分利用效率(WUE),但是当土壤含盐量超过一定水平时,WUE将随灌溉水矿化度的提高而显著降低;咸水灌溉使春玉米产量降低19.4%—57.9%,连续两年充分灌溉下矿化度为9g·L-1处理的产量仅为淡水的42%。【结论】咸水灌溉下,合理的降低灌溉水量有利于提高WUE,减少盐分积累,3g·L-1的水配合适当的淋洗可以作为后备灌溉水源。

Effect on Water-Salt Distribution and Evapotranspiration of Spring Maize Under Different Water Quantities and Qualities

【Objective】 The objective of the experiment was to investigate the effect of water quantity and quality on soil water-salt dynamic and water consumption of spring-maize. 【Method】 Field experiments were conducted in 2007-2008 in the middle reach of the Shiyanghe River Basin with different irrigation water quantities and salt concentrations. 【Result】 Results indicated that the effect of water quantity on soil water content was obvious in 60-100 cm soil layer. For salt concentration of 9 g?L-1 and 6 g?L-1 treatments, average soil water content of 20-100 cm kept higher than 25% in 2008. Total salt content increased with the increase of irrigation water concentration and decreased with the decrease of irrigation amount. Water deficit in a certain extent could also elevate water use efficiency（WUE） when irrigated with saline water, but WUE will be significantly reduced when increasing salt concentration in irrigation water when soil salinity exceeded a certain level. Yield of spring maize was reduced by 19.4%-57.9% under irrigation with saline water. Yield in treatment of irrigation with water of 9 g?L-1 of salt for two successive years was only 42% of that with fresh water. 【Conclusion】 Reduced irrigation amount reasonably was benefitial to increase WUE and decrease salt accumulation. Saline water which the salt conlent not exceeds 3 g?L-1 can be taken into account for supporting irrigation resource.