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 lack the mechanistic understanding to evaluate P retention in VBS and predict risks of P transport to aquatic ecosystems. We observed...

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Bibliographic Details
Published in:Environmental science & technology 2009-03, Vol.43 (6), p.1858-1863
Main Authors: Stutter, Marc I, Langan, Simon J, Lumsdon, David G
Format: Article
Language:English
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
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Summary: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.
ISSN:0013-936X
1520-5851
DOI:10.1021/es8030193