Vegetated buffer strips can lead to increased release of phosphorus to waters: a biogeochemical assessment of the mechanisms.
Establishing vegetated buffer strips (VBS) between cropland and watercourses is currently promoted as a principal control of diffuse pollution transport. However, we lackthe mechanistic understanding to evaluate P retention in VBS and predict risks of P transport to aquatic ecosystems. We observed that VBS establishment led to enhanced rates of soil P cycling, increasing soil P solubility and the potential amount leached to watercourses. Soil in VBS, relative to adjacentfields, had increased inorganic P solubility indices, dissolved organic P, phosphatase enzyme activity, microbial diversity, and biomass P. Small relative increases in the pool of soil P rendered labile had disproportionate effects on the P available for leaching. We propose a mechanism whereby the establishment of VBS on previous agricultural land causes a diversifying plant-microbial system which can access previous immobilized soil P from past fertilization or trapped sediment P. Laboratory experiments suggested that sediment-P inputs to VBS were insufficient alone to increase P solubility without biological cycling. Results showthat VBS management may require strategies, for example, harvesting vegetation, to offset biochemical processes that can increase the susceptibility of VBS soil P to move to adjoining streams.
The Macaulay Institute, Craigiebuckler, Aberdeen, AB15 8QH, United Kingdom. m.stutter@macaulay.ac.uk
Marc I
MI
Stutter
Simon J
SJ
Langan
David G
DG
Lumsdon
D000383:Agriculture; D010758:Phosphorus / Q000737:chemistry*; D010944:Plants; D013696:Temperature; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014877:Water Pollution, Chemical / Q000517:prevention & control*
D014874:Water Pollutants, Chemical; D010758:Phosphorus