海河平原秸秆覆盖和春季灌水对小麦玉米产量和水分利用的影响

Impacts on the yield and water use efficiency of wheat and maize under Spring-irrigation and straw mulching in Haihe Plain

针对海河平原水资源短缺和小麦-玉米水分利用现状,通过2013—2015年大田试验,设置春季不灌水、春季不灌水+秸秆覆盖、春季1水、春季1水+秸秆覆盖四个处理,研究了春季灌水和秸秆覆盖对小麦-玉米两熟作物生长、产量和水分利用的影响。结果表明:灌水和秸秆覆盖效应主要体现在小麦拔节到开花期。小麦拔节~开花期,由于灌溉和秸秆覆盖保温保墒作用,两个生长季中,春季1水秸秆覆盖LAI高于1水不覆盖处理,但开花期后这种效应逐渐消失,花后10天和20天覆盖LAI低于不覆盖处理,且差异显著;春季不灌水由于水分胁迫,无论秸秆覆盖与否,LAI差异不显著。2013—2014年,和不覆盖相比,春季0水覆盖产量降低了1.46%,春季1水处理覆盖后降低了2.76%;2015年春季0水覆盖降低了2.78%,春季1水覆盖降低了1.11%。但春季灌溉1水后,与不灌水相比,2014年产量差异显著,2015年差异不显著。随着灌溉水量的增加,土壤耗水量减少,两年中小麦生长季土壤耗水量都表现为春季0水大于春季1水,且差异显著;相同水分条件下不覆盖大于覆盖处理,但差异不显著。不同处理小麦生长季土壤耗水量的差异及玉米生长期间的降水量共同影响了玉米土壤耗水量,覆盖处理的耗水量小于不覆盖处理。从水分利用效率看,小麦、玉米和周年土壤水分利用效率各处理间和年份间都没有显著差异。海河平原水分有限条件下,秸秆覆盖后在小麦需水敏感期限量灌水在保证产量基础上可降低耗水量,因此春季灌溉1水结合秸秆覆盖是实现本区域小麦-玉米种植制度节水的有效措施。

Water scarcity in Haihe plain has a serious impact on water utilization and growth of wheat-maize double cropping system. To investigate the effects of spring-irrigation and straw-mulching on the crop growth,yield and water utilization of wheat and maize,four field-experiment treatments,Spring-no-irrigation,Spring-noirrigation/straw-mulching,Spring-irrigation once,and Spring-irrigation once/straw-mulching were carried out in 2013—2015. The results showed that,irrigation and straw-mulching had significant impacts on the crop during jointing-flowering stage of wheat. Due to preservation of soil moisture and soil temperature by straw-mulching during this stage,the LAI value with Spring-irrigation once/straw-mulching treatment scores significantly was higher than the Spring-irrigation once treatment. But the effects then gradually disappeared after flowering stage. The straw-mulching treatment had a significantly lower LAI value than no-straw-mulching treatment after 10 and 20 days from flowering. With or without straw-mulching,the LAI values with Spring-no-irrigation treatments were similar,probably due to the water stress. Compared with no-straw-mulching treatment,the yield of wheat decreased by 1. 46% under Spring-no-irrigation and decreased 2. 76% under Spring-irrigation in 2013—2014. Separately,the decreases were 2. 78% and 1. 11% in 2015. The Spring-irrigation once and no-irrigation treatmentshad a significant difference in crop yields in 2014,but not in 2015. With the increasing level of irrigation,the soil water consumption amount decreased. The soil water consumption in wheat growing was greatly increased with noirrigation treatment in spring than Spring-irrigation once treatment in the two years. No-straw-mulching had greater soil water consumption than straw-mulching treatment,though the difference was not significant. Together with the rainfall effect during maize growth,the effect caused a less soil water consumption with straw-mulching treatment than no mulching. For the water-use efficiency,wheat,maize and all the treatments in different years had no significant difference. Our results indicated that,straw-mulching guaranteed crop yield by decreasing soil water consumption during wheat water-sensitive stage under limited irrigation condition due to water scarcity in Haihe plain.The combination of spring-irrigation once with straw-mulching was very effective for water-saving wheat-maize double cropping system in the region.