关键词: 秸秆还田, 耕作措施, 耗水特性, 产量, 水分利用效率, 春小麦

Abstract:

【Objective】In oasis irrigated agricultural region, water resources scarcity is one of the most prominent constraints for crop production, which also leads to the unstable yield and the lower water use efficiency of crop production with conventional tillage. In this study, the characteristics of soil water utilization in spring wheat field with different straw retention approaches were investigated in the areas, so as to optimize the farming practices and to improve the water use efficiency. 【Method】A field experiment was carried out in a typical oasis irrigation region, Wuwei, Gansu Province, from 2014 to 2016, to determine the effects of treatments of straw retention patterns on soil water utilization of spring wheat field. The treatments included reduced tillage with 25 to 30 cm high straw standing (NTSS), reduced tillage with 25 to 30 cm high straw covering (NTS), conventional tillage with 25 to 30 cm high straw incorporation (TS), and conventional tillage without straw retention (CT, the control). 【Result】Reduced tillage with straw retention could decrease evapotranspiration of spring wheat field, furthermore NTSS and NTS treatments decreased evapotranspiration by 3.1% to 7.8%, 3.7% to 7.7%, compared to CT treatment, respectively. NTSS and NTS treatments decreased evapotranspiration of wheat before early-filling stage but increased it afterwards, so this created a more optimal balance between early- and late-stage water demand of spring wheat. NTSS and NTS treatments could enhance the effectiveness of water by inhibiting soil evaporation and reducing the proportion of evaporation to evapotranspiration (E/ET) for the spring wheat field. NTSS and NTS treatments reduced soil evaporation by 9.3% to 17.4% and 10.8% to 23.3% over CT treatment, and reduced by 4.0% to 5.8% and 5.6% to 11.4% over TS treatment, respectively. Among the two reduced tillage with straw retention treatments, NTS had the best effect on inhibiting soil evaporation, thus this treatment reduced E/ET by 6.9% to 21.3%. The grain yield of NTSS, NTS, TS was 16.6% to 24.9%, 18.6% to 27.3%, 10.2% to 18.7% greater than that of CT treatment, respectively, among the three straw retention treatments, NTSS and NTS had greater grain yield by 5.2% to 5.9% and 7.2% to 9.5% than that of TS treatment, respectively. Thus, straw retention treatments had greater water use efficiency (WUE), compared to CT treatment, NTSS, NTS, and TS treatments improved WUE by 21.1% to 28.3%, 26.6% to 30.6%, 13.1% to 20.3%, respectively. Across the three straw retention treatments, NTSS and NTS treatments improved WUE by 6.7% to 11.9%, 8.6% to 13.7%, in comparison to TS treatment, respectively. 【Conclusion】 Our results showed that reduced tillage in combination with 25 to 30 cm high straw standing and covering was the feasible technology for realizing high yield, stable yield and efficient utilization of irrigation water of spring wheat production in the oasis irrigation region.

Key words: straw retention, tillage practice, water consumption characteristics, yield, water use efficiency, spring wheat