Submitted to: Journal of the American Water Resources Association
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/9/2006
Publication Date: 2/1/2006
Citation: Dabney, S.M., Moore, M.T., Locke, M.A. 2006. Integrated management of in-field, edge-of-field, and after-field buffers. Journal of the American Water Resources Association. 42(1): 15-24 Interpretive Summary: Buffers protect the environment from adverse impacts associated with intense agricultural production. We reviewed three classes of buffers: in-field, edge-of-field, and after-field, and used examples to demonstrate how they can be integrated with each other and other conservation practices to create an integrated conservation system. Our results demonstrate how traditional grass and forest buffers can be combined with practices not usually considered buffers (grade control pipes and agricultural drainage ditches) to improve buffer functioning and better protect environmental quality. Our results are important to farmers, conservation planners, and regulators because they demonstrate the potential benefits associated with unconventional integration of several buffers types with each other and with other conservation practices.
Technical Abstract: Conservation benefits are maximized when in-field and edge-of-field buffers are integrated with each other and with other conservation practices such as residue management and grade control structures. Buffers improve both surface and subsurface water quality. Soils under permanent buffer vegetation generally have higher organic carbon concentrations, higher infiltration capacities, and more active microbial populations than similar soils under annual cropping. Sediment can be trapped with rather narrow buffers but extensive buffers are better at transforming dissolved pollutants. Buffers improve surface runoff water quality most efficiently when flows through them are slow, shallow, and diffuse. Vegetative barriers, narrow strips of dense erect grass, can slow and spread out concentrated runoff. Subsurface processing is best on shallow soils that provide increased hydrologic contact between the groundwater plume and buffer vegetation. Vegetated ditches and constructed wetlands can act as "after-field" conservation buffers, processing pollutants that escape from fields. For these buffers to function efficiently, it is critical that in-field and edge-of-field practices limit peak runoff rate and sediment yield in order to maximize contact time with buffer vegetation and minimize the need for cleanout excavation that destroys vegetation and its processing capacity.