Vegetated Buffer Strips Can Lead to Increased Release of Phosphorus to Waters: A Biogeochemical Assessment of the Mechanisms

• Published in: Environmental science & technology Vol. 43; no. 6; pp. 1858 - 1863
• Main Authors: Stutter, Marc I, Langan, Simon J, Lumsdon, David G
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.03.2009
• Subjects: Agriculture; Applied sciences; Aquatic ecosystems; Biochemistry; Biogeochemistry; Environmental Processes; Enzyme kinetics; Exact sciences and technology; Leaching; Phosphorus - chemistry; Phosphorus content; Plants; Pollution; Pollution control; Sediment transport; Temperature; Water Movements; Water Pollutants, Chemical - chemistry; Water Pollution, Chemical - prevention & control; Microbial activity; Fertilization; Solubility; Phosphorus; Sediments; Microbial biomass; Transport process; Ecosystem; Surface water; Vegetation; Lixiviation; Agriculture; Stream
• DOI: 10.1021/es8030193
• ISSN: 0013-936X

Establishing vegetated buffer strips (VBS) between cropland and watercourses is currently promoted as a principal control of diffuse pollution transport. However, we lack the 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 adjacent fields, 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 show that 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.