Stutter Marc I, Langan Simon J, Lumsdon David G
The Macaulay Institute, Craigiebuckler, Aberdeen, AB15 8QH, United Kingdom.
Environ Sci Technol. 2009 Mar 15;43(6):1858-63. doi: 10.1021/es8030193.
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.
目前，在农田与水道之间建立植被缓冲带（VBS）被视为控制面源污染扩散的主要手段。然而，我们缺乏对植被缓冲带中磷截留情况进行评估以及预测磷向水生生态系统迁移风险的机理认识。我们观察到，建立植被缓冲带会提高土壤磷循环速率，增加土壤磷的溶解度以及淋溶到水道中的潜在磷量。与相邻农田相比，植被缓冲带中的土壤无机磷溶解度指数、溶解有机磷、磷酸酶活性、微生物多样性和生物量磷均有所增加。土壤中不稳定磷库的相对小幅增加，对可淋溶磷产生了不成比例的影响。我们提出了一种机制，即在先前的农业用地上建立植被缓冲带会形成多样化的植物-微生物系统，该系统能够利用过去施肥中固定的土壤磷或截留的沉积物磷。实验室实验表明，仅靠向植被缓冲带输入沉积物磷，在没有生物循环的情况下不足以增加磷的溶解度。结果表明，植被缓冲带管理可能需要采取一些策略，例如收割植被，以抵消那些可能增加植被缓冲带土壤磷向相邻溪流迁移敏感性的生化过程。
