PhD studentship - Manipulation of plant diversity within grassland buffer margins to enhance soil biodiversity. TEAGASC

School of Applied Sciences

Cranfield University

Supported by TEAGASC Walsh Fellowships £14,200 p.a. is available*

Objectives

1. To establish ecosystem-level laboratory macrocosm experiments to study the effect of plant and soil biota community configuration on phosphorus mitigation, by manipulating plant community and soil biota interactions to determine the level of diversity required to enhance phosphorus mitigation.

2. Assessment of a range of field margins across a range of already established REPS sites to identify classes of plant community complexity.

3. To determine the soil biodiversity associated within the different classes of field margins identified above, and assess their likely impacts upon P capture and mitigation.

Summary

The establishment of a vegetated and unfertilised grass/woodland buffer strip/field margin alongside watercourses can reduce P diffuse pollution by acting as a sediment trap and intercepting overland flow. The degree of community complexity aboveground (with the incorporation of species to provide an annual cover and a range of physical structures) will affect the amount of sediment trapped.

Much work has been conducted looking at the effectiveness of buffer strips/field margins to capture nutrients resulting from diffuse pollution, however little information is available within the REP scheme to determine the effectiveness of a diverse plant community, or provide recommendations on optimal combinations of plant species. There have been many studies that look at the positive effect of above-ground plant diversity on soil biodiversity, but few have studied this relationship in respect to phosphorus capture and mitigation.

This study will focus on the interaction between above- and below-ground diversity and their roles in cycling of phosphorus in grassland field margins, using a range of techniques from laboratory-based macrocosm studies to field evaluation across a number of prescribed REPS sites. The outcome of this study will provide better understanding of the role of soil biodiversity in phosphorus mitigation and suggest best management strategies to produce field margins which will result in a reduction in P delivery to watercourses and concurrently meet the target of enhancing biodiversity in managed lands.