中文摘要：

针对我国西南地区旱作农田土层浅薄、水土流失严重、季节性干旱多发等问题,以常规平作（T）、垄作（R）、平作＋秸秆覆盖（TS）、垄作＋秸秆覆盖（RS）、平作＋秸秆覆盖＋腐熟剂（TSD）、垄作＋秸秆覆盖＋腐熟剂（RSD）6种措施作为处理,连续2年进行大田对比试验,研究不同保护性耕作措施对西南＂旱三熟＂种植区农田土壤生态要素、产量和水分利用效率的影响。结果表明,保护性耕作措施可以有效地改善土壤有机质和养分状况,且对酸性土壤有一定的改良作用,其中有秸秆覆盖的4个处理显著增加了土壤有机质、全氮、全钾、碱解氮含量;可改善土壤水分状况,增强作物的抗旱节水能力,各处理0~80 cm土层2年平均贮水量排序为：RSD（258.82 mm）〉TSD（252.40 mm）〉RS（250.19mm）〉TS（246.66 mm）〉R（239.19 mm）〉T（235.87 mm）;可降低7月份表层土壤温度,缓解夏季高温对玉米后期生长发育造成的伤害,其中有秸秆覆盖的4个处理对5 cm和10 cm土层温度有显著降低效应;可抑制杂草生长,具有良好的控草效应,其中TS、RS、TSD、RSD处理的杂草高度、密度和生物量均比T和R有极显著下降;可促进蚯蚓的繁殖和生长,使农田生态环境得到明显改善。总体来看,秸秆覆盖措施可以改善土壤肥力,并具有增加土壤贮水、调节土壤温度、控制农田杂草和促进蚯蚓生长的作用,垄作和腐熟剂在增加土壤贮水方面有明显效果。保护性耕作模式显著提高了作物的产量和水分利用效率,增加了经济收益。2年系统平均产量和水分利用效率排序为：RSD〉RS〉TSD〉TS〉R〉T（CK）,总产值和纯收入排序为RS〉RSD〉TSD〉R〉TS〉T（CK）。在各处理中以RSD、RS两种模式的综合效果最好,在西南＂旱三熟＂种植区具有很好的推广前景。

英文摘要：

Aimed at the problems such as shallow soil profile,severe soil and water erosion,and frequent seasonal droughts that are faced by the dryland agriculture in southwest China,a field experiment was conducted for two years to evaluate the influence of different conservation tillage measures on the soil ecological factors,yield and water use efficiency of crops in triple cropping system in dryland.There were six treatments including traditional farming（T）,ridge planting（R）,straw mulching（TS）,ridge planting ＋ straw mulching（RS）,straw mulching ＋ decomposing agent（TSD）and ridge planting ＋ straw mulching ＋ decomposing agent（RSD）.The results showed that the condition of soil organic matter and nutrients was improved effectively under the conservation tillage measures,in which the contents of soil organic matter,total N,total K and alkali-hydrolyzable N were significantly increased under four treatments with straw mulching,and the pH of acidic soil was raised to some extent.The soil moisture condition was improved,and the drought-resistant and water-saving ability of crops was strengthened under the conservation tillage measures.As for the 2-year mean water storage in 0-80 cm soil layer,the treatments could be ordered as：RSD（258.82 mm） TSD（252.40 mm） RS（250.19 mm） TS（246.66 mm） R（239.19 mm） T（235.87 mm）.The surface soil temperature in July was lowered under the conservation tillage measures,in which the temperature in 5 cm and 10 cm depth was significantly reduced under four treatments with straw mulching,thus easing the injury of high temperature on maize during late growth stage.The growth of weeds was inhibited effectively under the conservation tillage measures,and the average height,density and biomass of weeds under TS,RS,TSD,and RSD was extremely significantly lower than those under T and R.The reproduction and growth of earthworms were also accelerated under the conservation tillage measures,thus the farmland eco-environment was obviously improved.In general