Influence of phosphorus inputs and sheep treading on soil macrofauna and mesofauna in hill pastures

Abstract

Earthworm abundance increased and Oribatida abundance decreased on a Brown soil with increasing inputs of phosphorus (P) fertiliser and sheep stocking rates. To determine if the same response to increasing management intensity is found in Allophanic soil, samples were collected from a long-term sheep-grazed trial with two contrasting management regimes, low and high intensity. As pastures on the Allophanic soil became more productive and were grazed with more sheep, there was a tendency for earthworm abundance to increase and oribatid abundance to decrease. Both these trends were consistent with those on the Brown soil, supporting the potential of earthworms and Oribatida as biological indicators. Oribatid mites, which produce nutrient rich faecal pellets, were positively correlated with porosity. The higher earthworm abundances in more intensive sheep grazed pastures may have a positive influence on ecosystem services such as air and water movement, and organic matter incorporation.