Earthworm Communities and Microbial Metabolic Activity and Diversity under Conventional, Feed and Biogas Cropping Systems As Affected by Tillage Practices

Understanding management factors driving soil biota is pivotal to improve the sustainability of cropping systems, especially given the emergence of new cropping systems induced by bioeconomy. Here, we investigated the combined effects of tillage practices (tillage versus no-tillage) and contrasted cropping systems, including conventional, feed and biogas cropping systems, on earthworm communities and microbial metabolic activity and diversity (using Biolog Ecoplate). After three years, our results revealed that tillage overrode the effect of cropping systems on soil biota while being also detrimental for both earthworm communities and microbial activity and diversity compared with no-tillage. By contrast, no-tillage had generally a beneficial effect on soil microbial activity and earthworm abundance. More importantly, under no-tillage, feed and biogas systems increased microbial activity and diversity which was likely due to the higher crop diversity and the use of digestate instead of manure and slurry compared with the conventional system. Taken together, our findings show that both earthworm communities and microbial activity and diversity are very sensitive to tillage. Moreover, microbial activity and diversity are also rapidly affected by the type of cropping system, suggesting that it would be a better indicator to detect short-term changes in soil functioning following change in land use. Our study also indicates that, provided that no-tillage is included, biogas cropping system with high crop diversity can promote soil biota compared with conventional farming practices, leading likely to the improvement of soil functioning and ecosystem service delivery.