Does fertilizer type drive soil and litter macroinvertebrate communities in a sugarcane agroecosystem? Evidence from a 10-year field trial

Macroinvertebrates play a central role in processes supporting soil fertility. In the framework of the ecological intensification of agriculture, the choice of management practices should be guided by their ability to support these beneficial organisms supplying ecosystem services. This study aims at investigating the specific effect of partial substitution of synthetic fertilizers by locally produced organic fertilizers at a similar level of major nutrient inputs on macroinvertebrate abundance and diversity in sugarcane agroecosystems, on a Nitisol. Invertebrates visible to the naked eye were sampled in 2013, 2016, 2019 and 2023 using the standardized TSBF method on a long-term experimental field trial in Réunion island. The individuals were identified and soil samples were analyzed for physico-chemical properties. Despite the low response of macroinvertebrates to the fertilizer type, total macroinvertebrate abundance increased over time, especially isopods and earthworms. The input of organic carbon via the return of litter to the soil surface and the root turnover after each harvest enables soil macroinvertebrates to be more abundant even after replanting tillage. Mulching and root turnover are therefore important levers to consider for promoting macroinvertebrates in sugarcane agroecosystems. • The abundance of macroinvertebrates increases over time in sugarcane agroecosystem. • The abundance of saprophagous macroinvertebrates increases over time. • Fertilizer type has a limited effect on macroinvertebrate communities. • Litter and root turnover impact positively macroinvertebrate communities.