Large-scale ecologically-based farming systems foster earthworm communities and their contribution to ecosystem processes

In the Pampean region of Argentina, large-scale ecologically-based farming systems (EBS) are proposed as a more sustainable alternative to the conventional systems (CS). EBS rely on soil biological functioning, where earthworms are essential by their contribution to ecosystem processes such as nutrient cycling and soil aggregation. Our aim was to assess the effect of EBS, compared to CS and undisturbed grasslands (GS), on earthworm communities and their contribution to the process of soil structure formation, evaluated through direct sorting and quantification of earthworm casts. EBS and GS had similar earthworm richness and abundance, in both cases significantly higher than in CS. Earthworm biomass was higher in GS than in both farming systems and higher in EBS than in CS. Cast production was higher in EBS compared to CS, and similar in EBS and GS. Cast production was linearly related to earthworm abundance and to a greater extent to earthworm biomass. We conclude, in the first direct assessment of earthworm contribution to soil structure formation in EBS of the Pampean region, that this farming system provides better conditions for earthworm development compared to CS, enhancing their role in the soil ecosystem processes. Thus, we confirmed the ability of EBS to increase soil biological fertility replacing chemical inputs by ecosystem processes thus achieving more resilient and sustainable farming systems.