Aspects of water quality in the southern Piedmont: Attitudes, nutrients, and management for two typical agricultural watersheds

Nonpoint sources (NPS) of nitrogen (N) and phosphorus (P) from increasing population density and concentrated animal production have been earmarked as major causes of impaired water quality globally. In the Southern Piedmont, population densities and animal production are increasing, so strategies are needed to curtail the potential for NPS pollution. Implementation of strategies to minimize NPS pollution require: societal awareness and communication of the issue, sound knowledge of nutrient movement under different land management systems within fields, and identification of relationships between land management practices, landscape morphology, and nutrient concentrations in fluvial systems. In an effort to apply this strategy, we (1) measured farmer, educator, and researcher attitudes toward land use impacts on water quality with multidimensional scaling, (2) developed and evaluated a runoff collector (SIRC) for distributed landscape sampling, and (3) analyzed stream N and P concentrations for spatial distribution, relative to landscape position, fluvial morphological parameters, and management practices in stream-side fields. We found that farmers and educators identified erosion as having the highest impact on water quality. Researchers were most concerned with animal waste while livestock farmers were least concerned. Overall, highly visible phenomena were identified as having the greatest impact on water quality. Nutrient concentrations and mass loads measured from SIRC and miniwatershed (0.08 ha) flumes were not significantly different, indicating that placement of the SIRC in fields under various land management systems can further knowledge of nutrient movement in “real life situations”. Analysis of landscape morphology and nutrient concentrations indicated that increased drainage density increased nitrate concentrations in streams (p < 0.10), suggesting that highly dissected watersheds may be more vulnerable to nutrient inputs. Stream collection sites with stream-side fields in crops had higher ammonium concentrations than stream collection sites with stream-side fields in hay, pasture, or forest. There were no differences in dissolved reactive phosphorus (DRP) concentrations between crop, forest, or hay systems. Streams without grazing livestock had lower ammonium, nitrate, and DRP concentrations than streams with livestock present in the adjacent field. The N:P ratios for both streams (∼33) indicated that these streams are P-limited suggesting that P-based nutrient management plans could be highly effective.