Impact of Integrated Crop-Livestock Systems (ICLS) on soil microbial communities and fertility

Integrated crop-livestock systems (ICLS) combine livestock grazing on temporary grassland
sand/or cover crops, promoting efficient nutrient cycling. Although these systems improve soil
quality through manure deposition, their impact on soil microbial communities in temperate
climates is not well understood.
This study, conducted as part of the EcoFoodSystem trial at Gembloux Agro-Bio Tech in 2024,
explores how herbivore behavior and manure deposition during grazing affect soil microbial
activity, properties, and subsequent crop fertility. The study focuses on the effects of sheep
grazing on four multi-species temporary grasslands (grasses-legumes) and its impact on
subsequent maize crops.
Exclusion cages, with or without manure, were used to measure the impact on microbial
activity and soil properties over time (0, 3, 6, 13, 32, and 65 days after deposition).
Metagenomic analyses and DNA sequencing will identify microbial diversity, including
nitrifying bacteria and enzymatic activity such as β-glucosidase. Aerial images captured with
drones were used to assess grazing-induced spatial heterogeneity through NDVI calculation.
Preliminary results indicate changes in microbial activity linked to manure deposits. Aerial
images showed a reduction in NDVI, from 0.42–0.90 before grazing to 0.42–0.45 after. This
decrease, associated with increased spatial heterogeneity (NDVI SD: 0.02–0.12 to 0.15–0.22),
correlates positively (r = 0.697, p < 0.01) with manure density and vegetation regrowth.
In 2025, the study will focus on the persistence of spatial heterogeneity and its impact on
nutrient distribution and maize performance. This research enhances the understanding of
ICLS in temperate climates and their role in sustainable agriculture.