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Nonpoint-source pesticide pollution from horticultural and other agricultural activities is a primary factor determining the quality of surface water. A menu-driven, interactive pesticide transport submodel has been developed for the agricultural nonpoint-source (AGNPS) pollution model. AGNPS simulates the surface transport of pesticides, sediment, and water from the headwaters to the outlet in a stepwise manner so that an assessment can be made at any point within a watershed boundary. The model can be used by farmers, agricultural extension agents, agrichemical industry workers, or researchers to develop agricultural activities that minimize the surface transport of pesticides. This user-friendly pesticide transport model is available at no cost to users through the Internet.

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A pesticide transport submodel has been incorporated into a distributed parameter simulation model. AGNPS (AGricultural NonPoint Source Pollution Model) can evaluate the effect of agricultural pollution sources on surface runoff. Six pesticide classes are used: herbicides, insecticides, fungicides, nematicides, plant growth regulators, and desiccants/defoliants. User inputs for the model include the time of pesticide application (preplant, preemergence, or postemergence), application rate, application efficiency, percent canopy cover, soil and foliar pesticide residues, soil and foliar pesticide decay, water solubility, foliar washoff threshold and fraction, incorporation depth and efficiency, and sorption coefficient. Areas of pesticide losses and accumulations are indicated in tabular and graphical outputs. Alternative management practices can be simulated, and therefore assist in the optimization of practices to reduce pesticide runoff.

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of a larger mandated effort to reduce nonpoint source pollution. An educational program began in 2003 conducted primarily by the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) extension and supported by the Florida

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, 1992 ). Additionally, there were increased efforts to control non-point source pollution, which was primarily attributed to agriculture, but urban sources were explicitly recognized as contributors. The agreement also sought to explore “cooperative

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improperly timed fertilizer applications increase the risk of NPS pollution ( Law et al., 2004 ). Nonpoint source pollution is defined as any nondiscernable source in which pollutants are traveling, such as land runoff, precipitation, or drainage ( USEPA

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Due to increasing population and limited water supplies, legislatures are beginning to request that agriculture, including commercial greenhouse growers, reduce water inputs. State and federal governments are also concerned about nonpoint source

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Degraded water quality is a growing concern across the northeast and in many cases may be linked back to agricultural operations as nonpoint sources of nitrate and phosphorous pollution. Constructed wetlands have emerged as effective, low-cost methods of water treatment that have the potential to reduce agricultural nonpoint source pollution and contribute to agricultural sustainability. However, the costs of implementing treatment wetlands as a BMP are high, with little opportunity for cost recovery. We have initiated, at a wholesale plant nursery in Rhode Island, an economical solution to treating nursery runoff that incorporates into a treatment wetland the wholesale production of native and ornamental wetland plants. Our goal is to demonstrate how nursery growers may produce a high-demand crop while addressing nonpoint source pollution on their land. Over the next few years, we will evaluate the economic impact of converting nursery production space into treatment wetland production space. We also will research the feasibility of enclosing treatment wetlands in passively heated polyhouses to facilitate the year around treatment of agricultural runoff. Information gathered from both the on-farm demonstration and research sites will be extended to farmers and other agricultural businesses or professionals through outreach programming. The theory, objectives, and construction of the demonstration treatment-production wetland will be presented.

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Even with careful management, within-field practices are often insufficient to prevent considerable nonpoint source pollution to adjacent streams. Water resources suffer from sediment, N, and P transported in surface runoff and N in subsurface movement when fields are cultivated up to stream banks. The maintainance of forested buffer systems between farmland and streams has been proposed as a remedy for mitigating pollution. Chemical movement through such a buffer system has been monitored for several years at the University of Georgia Coastal Plain Experiment Station. With the aid of that data, the Riparian Ecosystem Management Model is being developed to simulate biological, chemical, and hydrologic processes in order to evaluate the effectiveness of buffer system management for reducing the influx of pollutants to streams. The model allows an examination of the long-term potential of a buffer system under changing environmental conditions.

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Primary environmental concerns regarding application of poultry litter (PL) for crop production are nitrate leaching into ground water and increased levels of P in the soil that can erode into surface water. This study was initiated to investigate use of warm- and cool-season annual forage crops to remove excess nutrients supplied by PL in rotational-cropping systems on a Bowie fine sandy loam (fine-loamy, siliceous, thermic, Plinthic Paleudults). PL was applied at one (1×) or two (2×) times the recommended rate in the spring, fall, or spring and fall. Rates were based on N requirement of the crop and percent N in the litter. Comparisons were made to fertilizer blends (FB) and control treatments with no PL or FB. After 3 years of treatments, NO3-N increased at the 122-cm depth by 30 and 50 mg·kg–1 from the 1× and 2× rate, respectively. The greatest accumulation was from FB (72 mg·kg–1). With PL applied in spring only, spring vegetables followed by a fall cover showed a significant reduction in NO3-N leaching and accumulation. Regardless of cropping system, rate, or time of application, P concentration increased by 40 mg·kg–1 in the surface 15 cm of soil when compared to FB. If applied in an environmentally sound manner, PL will be less of a threat to pollution of ground water than similar rates of FB. Applying PL rates sufficient to meet crop needs for N results in P accumulation that can lead to nonpoint source pollution of surface waters.

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The St. Johns River has been identified by the state of Florida as a priority water body in need of restoration. Best Management Practices were evaluated for potato (Solanum tuberosum L. `Atlantic') production in the Tri-County Agricultural Area to reduce nitrate run-off from about 9,300 ha in production. Objectives of this study were 1) determine the influence of soluble and controlled release fertilizer (CRF) and timing of leaching irrigation on nitrate leaching and 2) compare yield and quality of the potato crop fertilized with either a soluble or controlled release nitrogen fertilizer in a seepage irrigated production system. The experiment was a split-split plot with four replications. Main plots were irrigation events (0, 2, 4, 8, and 12 weeks after planting, (WAP)), nitrogen source and rates included (ammonium nitrate (AN) 224 kg·ha–1 or controlled release fertilizer (CRF) 196 kg·ha–1). About 7.6 cm of water was applied at each irrigation event and surface water runoff collected. CRF decreased NO3-N loading by an average of 35%, 28%, and 32% compared to AN fertilizer during the 2, 8, and 12 WAP irrigation events, respectively, compared to AN. Plants in CRF treatments had significantly higher total and marketable tuber yields (30 and 25 t·ha–1) compared to plants in AN treatments (27 and 23 t·ha–1), respectively. Plants in the CRF treatments also had significantly higher total and marketable yields in 2005 (28 and 23 t·ha–1) compared to plants in AN treatments (25 and 21 t·ha–1), respectively. CRF was an effective alternative to conventional soluble forms of fertilizer maintaining yields and protecting natural resources from nonpoint source pollution.

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