Relationship between the amounts of surface corn stover mulch and soil mesofauna assemblage varies with the season in cultivated areas of northeastern China

Crop residue management is an important conservation practice which provides numerous benefits to soil-related structural components and processes in agricultural ecosystems. However, the current understanding of the effects of soil environmental changes induced by different amounts of crop residue mulch on regulating soil mesofauna remains poor. To address this issue, an experimental field study was carried out in the Conservation Tillage Research and Development Station of the Chinese Academy of Sciences located in northeastern China. No-till and different amounts of corn stover mulch were included in a randomized complete block design with the following treatments: no-till with no corn stover mulch (NT-0); no-till with 2.5 t ha⁻¹ corn stover mulch (NT-33 %); no-till with 5 t ha⁻¹ corn stover mulch (NT-67 %); no-till with 7.5 t ha⁻¹ corn stover mulch (NT-100 %), and conventional tillage (CT) as a control treatment. Soil mesofauna were sampled in spring, summer, and autumn of 2016. The abundance, diversity, and composition of the mesofauna were measured to estimate the potential interacting effects on the mesofauna of no-till with different amounts of corn stover mulch. The results showed that compared with CT, no-till with corn stover mulch altered the mesofauna communities. NT-100 % harbored significantly more mesofauna than CT in spring, whereas higher densities of mesofauna were observed in NT-33 % and NT-67 % than other treatments in summer and autumn. The individual numbers of the majority of the mesofauna taxa in all no-till with corn stover mulch treatments were significantly higher compared with CT, particularly NT-100 % in spring and NT-67 % in summer and autumn. Although corn stover mulch had displayed beneficial roles in greatly contributing to the mesofauna assemblage, the relationship between the amount of corn stover mulch and the abundance of mesofauna changed across the growing season. The total density, richness, and the numbers of Oribatida, Isotomidae, Hypogastruridae, Neanridae, and Coleoptera had displayed significant linear relationships with the amount of corn stover mulch in spring. Meanwhile, the total density and the numbers of Mesostigmata, Hypogastruridae, Entomobryidae, and Diptera larvae had displayed significant 2nd degree polynomial relationships with the amount of corn stover mulch in summer and autumn. The results obtained in this study demonstrated that the corn stover mulch was the important factor in supporting more abundant and diverse mesofauna, however, the magnitude and direction of the effects of the amount of corn stover mulch on the mesofauna were highly seasonally specific.