Use of buffer zones or intact riparian areas is common practice to mitigate nutrient losses from agricultural areas that can impair water quality. However, much of the work assessing the impact of these conservation practices comes from watershed or regional-scale analyses linking water quality to land-use/land-cover metrics. We offer a finer-scale approach that utilizes rainfall simulators, a common soil science technique to assess sediment and nutrient loss in agricultural and developed land, to test the efficacy of riparian buffer strips to minimize nutrient or material losses. We replicated 5- to 10-year storm events with simulated storms on riparian banks immediately next to streams in restored tallgrass prairie, native tallgrass prairie, or intensively row-cropped farmland. The simulated rain contained an inert tracer, bromide, whose detection within the stream is used to quantitatively describe how quickly the precipitation moves through the riparian area. We monitored inputs of tracer, sediment, and nutrients (nitrogen and phosphorus) into streams. Relative losses of riparian nitrogen were higher than phosphorus at row-cropped farmland than tallgrass prairie. This methodological approach can help assess fine-scale riparian nutrient or material losses as a function of storm intensity and vegetation cover, soil type, and/or micro-topography.
Corman et al. (Fri,) studied this question.