中文摘要：

以高温伏旱区麦/玉/薯三熟为对象,研究了不同保护性耕作下旱地土壤水分动态变化、作物产量、水分利用效率和经济效应。结果表明：不同保护性耕作对产量和水分利用效率影响显著。垄作、秸秆覆盖和秸秆覆盖＋腐熟剂能提高系统0～80cm土层土壤含水量及贮水量,随着降雨量的增加,不同处理间的增加量增大。和平作（CK）相比,平作＋秸秆覆盖＋腐熟剂、垄作＋秸秆覆盖＋腐熟剂、垄作＋秸秆覆盖、平作＋秸秆覆盖、垄作分别使系统增产10.49%、9.73%、8.60%、8.11%、1.75%,且达到显著水平。垄作使水分利用效率只提高0.68%,效果不显著,而平作＋秸秆覆盖和平作＋秸秆覆盖＋腐熟剂使水分利用效率分别提高了6.23%和7.93%,达到显著水平。降水利用效率提高了4.80%～10.22%,其中垄作＋秸秆覆盖＋腐熟剂降水利用效率最高,平作＋秸秆覆盖的经济效益最大。研究结果显示,高温伏旱区三熟制在平水年中,采用平作＋秸秆覆盖或者平作＋秸秆覆盖＋腐熟剂的综合效益最好。

英文摘要：

The experiment was conducted to study the dynamic changes of soil water content,yield,water use efficiency（WUE） and economic benefit of wheat-maize-sweet potato triple cropping system in dryland of hot and summer drought areas under different conservation tillages.The results indicated that there were significant effects on yield and WUE.Ridge,straw mulch and straw mulch ＋ decomposing agent increased soil water storage and soil moisture in 0-80 cm depth,and the increase amount was raised as the rainfall increased.Compared with CK,traditional tillage ＋ straw mulch＋ decomposing agent,ridge ＋ straw mulch ＋ decomposing agent,ridge ＋ straw mulch,traditional tillage＋ straw mulch and ridge increased system yield by 10.49%,9.73%,8.60%,8.11%,1.75%,respectively,reaching to significant level.Ridge increased WUE only by 0.68%,being not significant.But traditional tillage＋ straw mulch and traditional tillage ＋ straw mulch＋ decomposing agent significantly increased WUE by 6.23% and 7.93%,respectively.Conservation tillages increased rainfall use efficiency by 4.80%-10.22%,in which ridge ＋ straw mulch ＋ decomposing agent was the highest in rainfall use efficiency,while traditional tillage＋ straw mulch was the highest in output/input ratio.It could be concluded that under normal rainfall condition,traditional tillage＋ straw mulch or traditional tillage ＋ straw mulch＋ decomposing agent could get the optimum comprehensive effects on wheat-maize-sweet potato triple cropping system in dryland of hot and summer drought areas.