The James Hutton Institute, Aberdeen, UK.
J Environ Qual. 2012 Mar-Apr;41(2):400-9. doi: 10.2134/jeq2010.0456.
The retention of nutrients in narrow, vegetated riparian buffer strips (VBS) is uncertain and underlying processes are poorly understood. Evidence suggests that buffer soils are poor at retaining dissolved nutrients, especially phosphorus (P), necessitating management actions if P retention is not to be compromised. We sampled 19 buffer strips and adjacent arable field soils. Differences in nutrient retention between buffer and field soils were determined using a combined assay for release of dissolved P, N, and C forms and particulate P. We then explored these differences in relation to changes in soil bulk density (BD), moisture, organic matter by loss on ignition (OM), and altered microbial diversity using molecular fingerprinting (terminal restriction fragment length polymorphism [TRFLP]). Buffer soils had significantly greater soil OM (89% of sites), moisture content (95%), and water-soluble nutrient concentrations for dissolved organic C (80%), dissolved organic N (80%), dissolved organic P (55%), and soluble reactive P (70%). Buffer soils had consistently smaller bulk densities than field soils. Soil fine particle release was generally greater for field than buffer soils. Significantly smaller soil bulk density in buffer soils than in adjacent fields indicated increased porosity and infiltration in buffers. Bacterial, archaeal, and fungal communities showed altered diversity between the buffer and field soils, with significant relationships with soil BD, moisture, OM, and increased solubility of buffer nutrients. Current soil conditions in VBS appear to be leading to potentially enhanced nutrient leaching via increasing solubility of C, N, and P. Manipulating soil microbial conditions (by management of soil moisture, vegetation type, and cover) may provide options for increasing the buffer storage for key nutrients such as P without increasing leaching to adjacent streams.
在狭窄的植被河岸带（VBS）中，养分的保留情况并不确定，其潜在过程也知之甚少。有证据表明，缓冲带土壤对溶解态养分（尤其是磷）的保留能力较差，如果要保持磷的保留，则需要采取管理措施。我们对 19 个缓冲带和相邻的耕地土壤进行了采样。通过对溶解态 P、N 和 C 形态以及颗粒态 P 的释放进行综合测定，确定了缓冲带和耕地土壤之间养分保留的差异。然后，我们利用分子指纹图谱（末端限制性片段长度多态性 [TRFLP]），探索了这些差异与土壤容重（BD）、水分、灼烧损失的有机质（OM）以及微生物多样性变化的关系。缓冲带土壤的有机质（89%的地点）、含水量（95%）以及溶解有机碳（80%）、溶解有机氮（80%）、溶解有机磷（55%）和可溶性反应磷（70%）的水溶性养分浓度明显更高。缓冲带土壤的容重普遍小于耕地土壤。与耕地土壤相比，土壤细颗粒的释放量通常更大。缓冲带土壤的容重明显小于相邻耕地，表明缓冲带的孔隙度和入渗性增加。与缓冲带和耕地土壤之间的土壤 BD、水分、OM 和缓冲养分的可溶性增加相比，细菌、古菌和真菌群落的多样性发生了显著变化。VBS 中当前的土壤条件似乎通过增加 C、N 和 P 的溶解度，导致潜在的养分淋失增加。通过管理土壤水分、植被类型和覆盖，可以改变土壤微生物条件，为增加关键养分（如 P）的缓冲储存提供选择，而不会增加对相邻溪流的淋失。
