Eleven-year mulching and tillage practices alter the soil quality and bacterial community composition in Northeast China

Conservation management is necessary to ensure soil sustainability. We investigated the response of soil chemical, biological properties, and bacterial community to 11 years of different mulch and tillage practices in an aeolian sandy soil in a maize continuous cropping system. Treatments included: no-till + straw coverage (ZT+R), rotary tillage + straw coverage (RT+R), and normal tillage (CT). Compared to CT, ZT+R and RT+R significantly increased total organic carbon (TOC) content, C:N ratio, available nitrogen (AN) content, and acid phosphatase (ACP) and urease activities, while decreasing soil pH in topsoil and subsoil. Moreover, RT+R enhanced C:N ratio and AN content and ACP and urease activities in deep soil. ZT+R increased bacterial richness and diversity; dominant phyla of Actinobacteria and Acidobacteria were found in topsoil and Gemmatimonadetes in subsoil and deep soil. However, RT+R showed negative effects on soil bacterial diversity and bacterial community because of severe soil disturbance. Redundancy analysis revealed that soil chemical properties (pH and TOC) are closely associated with soil bacterial communities. Therefore, long-term land management plays an important role in shaping microbial functional profiles. ZT+R is optimum for the enhancement of soil chemical properties and bacterial communities of aeolian sandy soils with a continuous cropping system.