[目的] 调查研究秸秆覆盖对黑土坡耕地表层土壤结构和导气性的影响,揭示秸秆覆盖措施对农田黑土土壤物理性状和功能的影响. [方法] 利用黑土农田保护性耕作连续7 a的坡耕地长期定位田间试验,系统观测秸秆覆盖免耕处理和传统耕作处理的表层0—10 cm的土壤容重、孔隙度、饱和含水量、田间持水量和土壤导气率等指标,并加以分析. [结果] (1)与秸秆移除传统耕作相比,秸秆覆盖免耕处理能够显著增加表层土壤容重、饱和含水量以及田间持水量,减少总孔隙度和非毛管孔隙度; (2)秸秆覆盖免耕处理使土壤水稳性团聚体显著增加,水稳性大团聚体(>0.25 mm)的含量、平均重量直径(MWD)和几何平均直径(GWD)分别提高了10.41%,45.28%和22.58%,且土壤表层导气性降低了30%. [结论] 连续7 a的秸秆覆盖免耕改善了表层土壤团粒结构,增加了保水能力,但导气性较差.
[Objective] The effect of straw mulching(SM) on topsoil structure and air permeability were investigated to reveal the influences of straw mulching on topsoil physical properties and function in black soil sloping farmland. [Methods] This study was based on a long-term (7 years) field observation experiment of conservation tillage on black soil. Topsoil(0—10 cm) bulk density, porosity, saturated water content, field capacity, soil water stable aggregate and air permeability was analyzed and compared between straw mulching and conventional tillage(CT) field experiments. [Results] (1) The topsoil bulk density, saturated water content and field capacity of SM were higher than that of CT, while the soil total porosity and non-capillary porosity of SM was lower than that of CT.(2) Compared to the CT, topsoil water stable aggregate content (>0.25mm), mean weight diameter and geometric weight diameter in the SM soil was increased the by 10.41%, 45.28% and 22.58%, respectively, while soil air permeability was decreased by 30%. [Conclusion] Continuous 7-year SM improved the topsoil aggregate structure and water retention, but decreased the air permeability in black soil sloping farmland.