Reducing the export of nitrogen (N), phosphorus (P), and sediment from agricultural land in water-supply watersheds is a continuing goal in central North Carolina. The objective of this project was to document the effectiveness of a combination of livestock exclusion fencing and nutrient management implemented on a beef cattle pasture located in the Piedmont region of North Carolina. The quantity and quality of discharge from two predominantly pasture watersheds were monitored simultaneously for 3.8 yr before and after implementation of the exclusion fencing and nutrient management in the treatment watershed; a control watershed remained unchanged. The excluded stream corridor was intentionally minimized by constructing the fence line about 3 m from the top of the streambank on either side and limiting it to the main stream channel only. Monitoring included collecting flow-proportional samples during storm events and analyzing them for total Kjeldahl N (TKN), ammonia (NH 3 -N), and inorganic (NO x -N) N as well as total P (TP) and total suspended solids (TSS). Statistically significant reductions were observed in TKN (34%), NH 3 -N (54%), TP (47%), and TSS (60%) loads in the treatment relative to the control watershed after fencing, whereas storm discharge and NO x -N loads were not significantly different. These data show that even a relatively narrow exclusion corridor implemented on only the main stream channel can significantly reduce the export of N, P, and sediment from a beef cattle pasture. Effectiveness of Livestock Exclusion in a Pasture of Central North CarolinaDaniel E. Line,* Deanna L. Osmond, and Wesley Childres J ordan Lake (Reservoir), located in central North Carolina, is a 5650-ha impoundment with a 436,860-ha watershed of which 18% was urban, 20% agricultural, and 56% forested. Like many lakes in the eastern United States, the use of this water resource is being threatened by excessive nutrient inputs. A proposed nutrient reduction strategy set overall nitrogen (N) and phosphorus (P) load reduction goals for the watershed at 8 to 35% for N and 5% for P. As a result, the agricultural and urban communities began to look for ways of reducing N and P loads to surface waters. Agricultural land use in the Jordan Lake watershed consisted of a plurality of acres in pasture or hay (>75%); thus, the focus of N and P reduction efforts was directed toward cost-effective best management practices (BMPs) for pastures (Osmond and Neas, 2007

Spence, Porchè L., Deanna L. Osmond, Wesley Childres, Joshua L. Heitman, and Wayne P. Robarge, 2012. Effects of Lawn Maintenance on Nutrient Losses Via Overland Flow During Natural Rainfall Events. Journal of the American Water Resources Association (JAWRA) 48(5): 909‐924. DOI: 10.1111/j.1752‐1688.2012.00658.x Abstract:  A sampling system was used to evaluate the effect of residential lawn management on nutrient losses via overland flow generated during natural rainfall events from three residential landscapes: a high maintenance fescue lawn (HMFL), a low maintenance fescue lawn (LMFL), and a mixed forested residential landscape (FRL). A sampling system was located in designated areas within each landscape such that 100% of the runoff follows natural flow paths to the outlet ports and collects in sterile Nalgene® B3 media bags (Thermo Fisher Scientific, Rochester, NY). A rainfall event was defined as producing ≥2.54 mm of water. A total of 87 rainfall events occurred during a 20‐month monitoring period. The total runoff volume collected from the LMFL was higher than from the HMFL and FRL, but on average <1% of the total rainfall was collected from the three landscapes. Mean nitrate concentrations from each lawn did not exceed 0.6 mg N/l. Nutrient unit area losses from the HMFL, LMFL, and FRL were 1,000 times less than fertilizer and throughfall inputs, which were due to the presence of well‐structured soils (low bulk densities) with high infiltration rates. This study demonstrated that the frequency of runoff, total runoff volumes, and nutrient losses during natural rainfall events are lower from highly maintained (i.e., irrigation, fertilizer application, and reseeding) densely uniform manicured lawns than low maintenance lawns and forested residential landscapes.

Abstract. Nitrogen (N) and phosphorus (P) input and export rates were determined in six rural, predominantly agricultural watersheds located in the Piedmont and Coastal Plain regions of North Carolina. Water quality monitoring was conducted at the outlets for 2.3 to 8.0 years to determine the annual N and P export from each watershed. Total N and P input and export from five of the six watersheds were correlated, with only a no-till cropland watershed differing. The correlation showed that N and P exports increased by about 4.0% and 8.7%, respectively, of applied N and P for the range of applications rates, whereas dissolved N (NOx-N) export increased by 2.8% with increasing N application rates. Therefore, practices that reduce inputs, such as nutrient management, should result in similar percentage reductions in exports. The Small Watershed Nutrient Forecasting Tool (SWIFT) was used to forecast discharge, N, P, and sediment export from each of the six watersheds. For the no-till cropland watershed, the SWIFT-forecasted N and P export rates were more than 2.5 times those measured, while the sediment export rate was 72 times the measured value. Thus, these data showed that the SWIFT forecasts for N, P, and sediment export were poor for the no-till cropland watershed. For the pasture watershed, the SWIFT forecasts for N and sediment export agreed reasonably well with measured export; however, the forecasted P export was much less than measured. For the four mixed land use watersheds, the SWIFT forecasts for discharge, TN, and sediment were mostly greater than measured, and the forecasted TP export was less than measured for three of the four watersheds. Thus, as with many predicstion tools, SWIFT results must be used with caution. Keywords: Nutrient export, Nutrient management practice, Water quality monitoring.