论文部分内容阅读
在黄土高原西部连续5年定位观测了4种耕作措施[传统耕作(T);传统耕作+秸秆覆盖(TS);免耕(NT)和免耕+秸秆覆盖(NTS)]下春玉米-冬小麦-夏大豆轮作系统中的水分动态及其水分利用效率,结果表明:土壤含水量受降水的影响较大,年内和年际的变率大,200 cm内土壤含水量在350~600 mm变动;土壤贮水量5—7月上旬因作物利用迅速下降,在雨季得到补充,到冬季缓慢下降;水保耕作措施对玉米Zeamays、小麦Triticum aestivum和大豆Glycine max生育期200 cm土体耗水量影响不大,但秸秆覆盖能有效增加玉米-小麦-大豆轮作系统的水分利用效率;与传统耕作相比,免耕没有造成轮作系统的减产和水分利用效率的降低,免耕、秸秆覆盖可增加农民收入;在土地利用强度极高的玉米-小麦-大豆轮作系统,改大豆为利用营养体的豆科牧草,可提高系统的水分和光能利用率。
Four kinds of tillage practices (conventional tillage (T); traditional tillage + straw mulching (TS); no tillage (NT) and no-tillage + straw mulching (NTS) The results showed that the soil water content was greatly influenced by precipitation, the annual and interdecadal variability was large, and the soil water content within 200 cm ranged from 350 mm to 600 mm. Soil water storage decreased rapidly in early May and early July due to crop utilization, but decreased slowly in winter and then decreased slowly in winter. Water conservation measures had little effect on water consumption in 200 cm soil of Zeamays, Triticum aestivum and Glycine max , But the straw mulching could effectively increase the water use efficiency of the corn-wheat-soybean rotation system. Compared with the traditional tillage, no-tillage did not result in the reduction of crop rotation system and water use efficiency, and the no-tillage and straw mulching increased the farmers’ income. In the highly land-intensive corn-wheat-soybean rotation system, changing soybean to nutrient-based leguminous forages can improve the system’s water and light energy utilization.