Remediation of grassland soils excessively fertilised with phosphorus

• Research unit: COST
• Project number: C99.0056

Key words (English)

Phosphorus; availability; P immobilisation; P losses; runoff; field experiment; pastures; fertilisation; soil structure

Research programs (English)

COST-Action 832 - Agricultural contribution to Eutrophication

Short description (English)

See abstract

Partners and International Organizations (English)

A, B, DK, FIN, F, D, GR, H, IRL, I, NL, N, PL, RO, E, S, CH, GB

Abstract (English)

Accumulation of available phosphorus (P) in the superficial horizons of grassland soils, mainly caused by high application rates of slurry and manure, result in increased diffuse P losses leading to eutrophication of surface waters. Research conducted during the last decades on P transport showed that surface run-off and leaching are major pathways for P losses from grassland soils. However, little is known on the processes controlling these losses. This project had two main tasks: - To propose and test specific remediation measures at the field scale, so as to reduce P losses from grassland soils to water. - To study the processes governing the transfer of P from grassland soils to surface runoff (P mobilisation, interaction of soil P and mobile water with special respect to the role of soil structure, contribution of different P fractions to losses). The research was carried out in two field sites located on sloped permanent grasslands within the Greifensee watershed (Grüningen, Girenbad) and in the laboratory. Four different treatments were implemented in the field (zero P: no P fertilisation, tillage: single tillage + zero P and amendment: single tillage + precipitation of Fe-hydroxide + zero P). One of the applied remediation measures (amendment) reduced dissolved reactive P concentration in surface runoff and P availability in the topsoil. The tillage treatment considerably reduced P availability, but did not affect P losses. The treatment zero P showed no effect on P availability and P losses. The grass yield was not negatively affected by any of the treatments.Further investigations would be necessary to evaluate the long term effects of these treatments.

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C99.0056