秸秆还田是干旱地区广泛应用的作物高效生产技术，但其能否通过改善作物生理生态特性而进一步提高产量还需实践验证。在甘肃河西绿洲灌区，通过田间试验，研究了不同秸秆还田方式[免耕秸秆覆盖还田(NTSM)、免耕秸秆立茬还田(NTSS)、传统翻耕秸秆还田(CTS)及传统翻耕无秸秆还田(CT, 对照)对小麦生理生态特性的调控效应，以期阐明秸秆还田影响小麦产量的生理生态机制。结果表明，NTSM和NTSS处理对小麦生理生态特性的调控作用优于CTS和CT而获得较高产量，NTSM因较优的调控效应使其增产幅度略高于NTSS。与CT相比，NTSM降低了小麦孕穗期之前的叶面积指数为6.1–7.6%，提高孕穗期之后的叶面积指数为38.9–45.1%，NTSM可有效地调控小麦光合源动态。NTSM较CT提高小麦灌浆期与蜡熟期光合速率为10.2–21.4%与11.0–21.6%，提高蒸腾速率为4.4–10.0%与5.3–6.1%，提高叶片水分利用效率为5.6–10.4%与5.4–14.6%。与CT相比，NTSM提高小麦抽穗期至蜡熟期叶片与土壤水势分别为7.5–12.0%与8.9–24.0%。NTSM较CT降低了小麦叶-土水势差，表明NTSM处理有利于保持干旱条件下小麦植株水分需求和土壤水分供给的稳定性。NTSM较CT增产18.6~27.3%，其增产归因于穗数、穗粒数和千粒重的协同增加。因此，免耕秸秆覆盖还田是干旱灌区优化小麦生理生态特性及获得高产的可行栽培措施。

Studies on root development, soil physical properties, grain yield, and water-use efficiency are important for identifying suitable soil management practices for sustainable crop production. A field experiment was conducted from 2006 through 2008 in arid northwestern China to determine the effects of four tillage systems on soil properties, root development, water-use efficiency, and grain yield of winter wheat (Triticum aestivum L.). The cultivar Fan 13 was grown under four tillage systems: conventional tillage (CT) without wheat stubble, no-tillage without wheat stubble mulching (NT), notillage with wheat stubble standing (NTSS), and no-tillage with wheat stubble mulching (NTS). The soil bulk density (BD) under CT system increased gradually from sowing to harvest, but that in NT, NTSS, and NTS systems had little change. Compared to the CT system, the NTSS and NTS systems improved total soil water storage (0-150 cm) by 6.1-9.6 and 10.5- 15.3% before sowing, and by 2.2-8.9 and 13.0-15.1% after harvest, respectively. The NTSS and NTS systems also increased mean dry root weight density (DRWD) as compared to CT system. The NTS system significantly improved water-use efficiency by 17.2-17.5% and crop yield by 15.6-16.8%, and the NTSS system improved that by 7.8-9.6 and 7.0- 12.8%, respectively, compared with the CT system. Our results suggested that Chinese farmers should consider adopting conservation tillage practices in arid northwestern China because of benefits to soil bulk density, water storage, root system, and winter wheat yield.