不同绿肥和覆膜措施对渭北旱塬冬小麦产量和土壤水分动态的影响

  【目的】  冬小麦—绿肥轮作在干旱贫水年份易导致冬小麦减产，我们研究了平水年和干旱年旱地绿肥和覆膜措施相结合对小麦产量及水分利用率的影响，为建立科学高效的小麦–绿肥轮作体系奠定基础。  【方法】  田间试验于2017—2019年布设在陕西省永寿县御驾宫乡御中村，试验采用裂区试验设计，以轮作不同绿肥品种(黑麦豆、油菜，夏休闲为对照)为主处理，覆膜措施为副处理，设常规耕作和垄覆沟播两个水平。在冬小麦返青期、开花期、收获期调查小麦苗期生长状况、产量形成、水分利用效率和麦田0—200 cm土壤水分动态变化。  【结果】  1)平水年和干旱年，轮作油菜的冬小麦产量高于轮作黑麦豆，两年间轮作油菜处理比轮作黑麦豆处理的冬小麦产量分别高出 9.3%和43.5% (P<0.05)。2)采用垄覆沟播，轮作绿肥显著降低了冬小麦生育期耗水量，平水年提高了冬小麦的水分利用效率。平水年轮作油菜的水分利用效率最高14.3 kg/(hm2·mm)]，比夏休闲处理增加了7.4%；而干旱年轮作绿肥降低了冬小麦的水分利用效率，与夏休闲相比轮作黑麦豆和油菜处理分别降低58.5%和38.3% (P<0.05)。轮作绿肥与垄覆沟播对提高小麦水分利用效率有显著的交互作用。3)轮作绿肥并垄覆沟播的栽培模式加重了土壤水分的消耗。相比于夏休闲，平水年冬小麦播前0—200 cm土壤贮水量平均降低10.1% (P<0.05)，干旱年平均降低15.7% (P<0.05)。  【结论】  我国渭北旱塬地区在平水年采用种植油菜+垄覆沟播新型种植模式，可以在保证不减产的情况下提高冬小麦的水分利用效率，但干旱年小麦产量和水分利用效率均会受到负面影响。

Effects of different green manure crops and mulching approaches on wheat yield and soil moisture dynamics in the dryland region

  【Objectives】  Green manure (GM) rotation of winter wheat can reduce crop yield in dry years. Here, we explore the effects of combining dryland green manure and film mulching measures on wheat yield and its dynamics of water use efficiency (WUE, 0–200 cm soil depth) in normal and dry years to establish a science-based efficient wheat green manure rotation system.  【Methods】  A short-term field experiment with a split-plot design was conducted in Yongshou County, Shaanxi Province from 2017 to 2019. The main plot was the different GM crops, including the black bean and rapeseed, and summer fallow was the control. The sub-plot was the plastic mulching practices, including conventional tillage (CK), and ridge-mulching and furrow-seeding practices. Data of winter wheat yield and WUE were collected at reviving stage, flowering stage, and harvesting stage.  【Results】  1) In the normal and dry years, the winter wheat yield in the rapeseed treatment was (P < 0.05) higher than the black bean treatment (9.3% vs. 43.5%). 2) Under the conditions of ridge-mulching and furrow-seeding, planting GM crops (P < 0.05) reduced winter wheat water consumption during the growth period increased its WUE in the normal year. In the normal year, the WUE of wheat in the rapeseed reached the maximum 14.3 kg/(hm2·mm)], which was 7.4% higher than fallow. In the dry year, GM crops reduced the WUE of wheat by 58.5% in black bean and 38.3% in rapeseed, compared with fallow. We found a significant (P < 0.05) interaction effect of GM and ridge-mulching and furrow-seeding approaches on winter wheat WUE. 3) Planting GM crops with ridge-mulching and furrow-seeding increased soil moisture consumption. Compared with the summer fallow treatment in the normal and dry years, the soil water storage at a depth of 0–200 cm before sowing winter wheat (P < 0.05) reduced by 10.1% and 15.7%, respectively.  【Conclusions】  Growing rapeseed as a GM crop with ridge-mulching and furrow-seeding improved the WUE of winter wheat without reducing crop yield. However, there was a reduction in wheat yield and WUE in the dry years.