Successful plant growth depends on a fertile soil that provides the plants with sufficient water and nutrients. This requires a suitable soil structure to facilitate root anchorage and a healthy soil microbiota to perform the necessary soil services. Moreover, it is essential that the soil is stable to prevent erosion.
Soil aggregates are an essential prerequisite to fulfil these criteria. Soil aggregates are small clusters of primary soil particles, i.e. sand, silt, and clay arranged around soil organic matter. Soil aggregation is the result of both biological and physicochemical processes that glue organic and mineral contents together into a web. Extensive soil aggregation will improve root growth, beneficial microbial activity, and transport of gasses, water and plant mineral nutrients.
Bacteria and fungi are the key components in soil aggregate formation. They exude the gluing matrix and provide physical links between different particles. Arbuscular mycorrhizal fungi have a key-role. When their extensive mycelium proliferate in the soil, they directly support soil aggregation and further they connect soil aggregates with the plant roots, which increase soil fertility. Still, the relative importance of various trophic and functional groups e.g. protists is largely unknown; a knowledge gap the proposed research will bridge as we target various trophic groups concomitantly in the same experimental setups.
In AGGREGATE, we aim to identify key factors that affect soil aggregation positively or negatively. We will specifically test how inclusion/exclusion of specific functional soil biota impact soil aggregation. Moreover, we will examine how certain agricultural practices diminish aggregation with focus on specific pesticides that inhibit key soil biological components. AGGREGATE challenges the usefulness of current standard tests for un-wanted side effects of pesticides and propose a holistic and realistic soil model for proper testing.