不同覆盖时期和覆盖方式对旱地冬小麦经济和环境效应的影响

【目的】明确不同覆盖时期（夏闲期和周年覆盖）以及不同覆盖方式（垄沟覆盖、全膜覆盖和秸秆覆盖）对旱地冬小麦产量、经济效益和温室气体排放的影响,为选择适合当地小麦生产的高产、高效和环境友好型覆盖措施提供科学依据。【方法】于2017—2019年2个小麦生长季在黄土高原典型旱作区陕西省永寿县开展大田试验,试验设6个处理,采用裂区设计。不同覆盖时期为主区,设置夏闲期覆盖和周年覆盖（生育期覆盖+夏闲期覆盖）2个处理,不同覆盖方式为副区,分别为垄膜沟秸秆全地面覆盖、全膜覆盖以及秸秆全地面覆盖3个处理。研究分析小麦产量、土壤蓄水量、生育期耗水量、水分利用效率、经济利润以及温室气体排放强度。【结果】与夏闲期覆盖相比,周年覆盖2季平均增产9.5%,周年秸秆覆盖平均产量较周年垄覆沟播处理高出622 kg·hm^-2,而与全膜穴播处理没有显著差异;周年覆盖生育期耗水量和水分利用效率较夏闲期覆盖分别提高5.6%和4.0%;周年覆盖可显著提高冬小麦经济效益,较夏闲期覆盖年平均净利润提高17.8%,周年覆盖中秸秆覆盖平均净利润>全膜穴播>垄覆沟播;同时,周年覆盖2季平均温室气体排放强度较夏闲期覆盖降低11.0%,差异达显著水平。其中,以周年秸秆覆盖的温室气体排放强度最低。【结论】与夏闲期覆盖相比,周年覆盖措施能够提高水分利用效率和生育期耗水量从而提高冬小麦产量和经济效益,同时减少温室气体排放强度。其中,周年秸秆覆盖措施具有较好的经济效益和最低的温室气体排放强度,适宜在黄土旱塬区冬小麦生产中推广应用。

Effects of Different Mulching Periods and Mulching Practices on Economic Return and Environment

【Objective】 The objective of this study was to clarify the effects of different mulching periods (mulching during the summer fallow and the year-round mulching) and different mulching practices (ridge-furrow plastic mulching, whole field plastic mulching and straw mulching) on winter wheat yield, economic return and greenhouse gas emissions in dryland. 【Method】 The experiment was carried out from 2017 to 2019 in Yongshou Country, Shaanxi Province, which was a typical rainfed farming area of the Loess Plateau. The split plot design was employed with main plot of different mulching periods (mulching during the summer fallow and mulching over the year), and sub-plot of different mulching practices (ridge-furrow plastic mulching, whole field plastic mulching and straw mulching). Wheat yield, soil water storage and evapotranspiration during the winter wheat growing season and water use efficiency, economic profit and greenhouse gas emission intensity were analyzed. 【Result】 Compare to mulching practices during the summer fallow, the average yield of year-round mulching practices was increased by 9.5%. The average yield of annual straw mulching was 622 kg·hm^-2 higher than that of annual ridge-furrow plastic mulching, but there was no significant difference between the year-round straw mulching and year-round plastic film mulching. Compare to mulching practices during the summer fallow, the year-round mulching practices increased the evapotranspiration during the winter wheat growing season and water use efficiency by 5.6% and 4.0%, respectively. Compared to mulching practices during the summer fallow, the year-round mulching practices significantly increased the economic return of winter wheat by 17.8%, and the average net economic return was straw mulching>plastic film mulching>ridge-furrow plastic mulching among the year-round mulching practices. Moreover, compared to mulching practices during the summer fallow, the average greenhouse gas emission intensity of year-round mulching practices decreased of 11.0%, and the difference was significant. The lowest greenhouse gas emission intensity was in annual straw mulching. 【Conclusion】 Compared to mulching practices during the summer fallow, the year-round mulching practices could improve water use efficiency and evapotranspiration during the winter wheat growing season, thus improving the yield and economic returns of winter wheat, while reducing the intensity of greenhouse gas emissions. In all practices, the annual straw mulching had the best economic return and the lowest intensity of greenhouse gas emissions, which was suitable for popularization and application in dryland winter wheat production areas.