少免耕对灌溉农田冬小麦/夏玉米作物水、肥利用的影响

Impacts of minimum tillage and no-tillage systems on soil NO_3^--N content and water use efficiency of winter wheat/summer corn cultivation

土壤耕作可影响土壤硝态氮的淋失、土壤的贮水量和作物的水分利用效率。为了研究少免耕在冬小麦套作夏玉米一年两熟灌溉农田对作物产量、水分利用效率和土壤硝态氮含量的影响,采用了5种土壤耕作体系(常规耕作无秸秆还田、常规耕作秸秆还田、旋耕秸秆还田、缺口圆盘耙耕秸秆还田、免耕秸秆覆盖)在山东龙口进行了田间试验。利用烘干法测定了土壤含水率,利用连续流动分析仪测定了土壤硝态氮的含量。结果表明:相对于常规耕作,少耕特别是旋耕还田方式能够增加土壤贮水量、提高作物水分利用效率和全年作物产量,提高土壤0~60cm层次硝态氮含量、减少硝态氮的淋失。以旋耕还田为主的耕作体系可以在该地区应用,而免耕覆盖则不适宜。

In order to research the impacts of minimum tillage and no-tillage on crop yield, crop water use efficiency and soil NO3^--N content under the condition of winter wheat/relays summer maize cultivation and irrigation field, five tillage systems were adopted in Longkou city, Shandong Province. The five tillage systems were as follows： conventional tillage without straw turnover , conventional tillage with straw turnover, rotary tillage with straw turnover, serrated disk harrow tillage with straw turnover, no-tillage with straw cover. The soil moisture content was measured by oven drying method. The soil NO3^--N content was measured by continued flow analysis extraction. Results showed that minimum tillage especially rotary tillage with straw returned could increase soil water content, water use efficiency and crop yield in a whole year, NO3^--N content in 0-60 cm layer of soil and decrease the leaching loss of NO^3--N in soil. Preliminary studies showed that rotary tillage with straw turnover could be adopted in this region, while no-tillage with straw cover returned was not suitable.