滴灌条件下秸秆覆盖与施肥对夏玉米土壤水分的影响

Effects of Straw Mulching and Fertilization on Soil Moisture of Summer Maize with Drip Irrigation

设置2种覆盖处理（不覆盖,覆盖5 500kg/hm2）及3种施肥处理（低肥0kg/hm2,中肥200kg/hm2,高肥400kg/hm2）,研究了滴灌条件下,秸秆覆盖和不同施肥处理对夏玉米土壤棵间蒸发以及土壤含水率等的影响。试验结果表明,滴灌带两侧干湿区域棵间蒸发量差异显著,各处理全生育期湿润区域比干燥区域多出14.5~34.13mm,增加比例为13.34%~21.08%。秸秆覆盖减少棵间蒸发的作用显著,全生育期3种施肥处理覆盖比不覆盖分别减少36.31 mm,45.19 mm,49.29 mm;减少的比例依次为27.32%,30.47%,32.59%;日均分别减少0.35mm,0.43mm,0.47mm。秸秆覆盖对不同深度土壤的水分分布具有调节作用,在0—20cm土层保水效果明显。生育期内平均的叶面积指数变化趋势为先增后减,变化规律为生育中期〉生育末期〉快速生长期〉生育初期。各处理E/ET与LAI均表现出较好的指数相关关系,不覆盖处理的决定系数大于覆盖处理。可见,秸秆覆盖可以有效减少棵间蒸发量,同时调节不同深度土壤水分含量,提高土壤表层作物可利用水分含量。

This research was conducted based on 2kinds of cover treatments（not covered,and covered with straw of 5 500kg/hm2）and 3types of fertilizer treatments（low fertilization（0kg/hm2）,middle fertilization（200kg/hm2）,and high fertilization（400kg/hm2））in order to study the effects of straw mulching and fertilization on soil moisture of summer maize under drip irrigation.The results showed that,on both sides of drip lines,the dry and wet zone were significantly different in soil evaporation.During the whole growth period,soil evaporation in wet zone increased by 14.5~34.13 mm compared to that in dry zone,with the increase ratio of 13.34%~21.08%.Effect of straw mulching in reducing soil evaporation was remarkable.Compared to non-mulching treatment,straw mulching treatment decreased soil evaporation by 36.31 mm,45.1mm and 49.29 mm,respectively,under 3fertilizer treatments during the whole growth period,with the decrease proportion of 27.32%,27.32%and 30.47%,and with the average daily reduction of 0.35 mm,0.43 mm and 0.47 mm.Straw mulching had a regulatory role on distribution of soil moisture of different depth.In 0—20cm soil layer,straw mulching had a beneficial role in water retention.The trend of the average leaf area index increased at first and then decreased.The order of the average leaf area index at different growth stages was the middle growing stagethe〉 the later growing stagethe〉the rapid growing stage〉the earlier growing stage.E/ET and LAI of all the treatments showed better index correlation,and decision coefficient of non-mulching treatment was greater than that of mulching treatment.In short,straw mulching can effectively reduce the soil evaporation.Straw mulching can also adjust the water content of soil at different depths and promote the water content of surface soil available for crops.