Search

To better understand, implement, and integrate best management practices (BMPs) in agricultural watersheds, critical information on their effectiveness is required. A representative agricultural watershed, Beasley Lake, was used to compare runoff water quality draining through an integrated system of BMPs from row crop cultivated subdrainages as part of the national Conservation Effects Assessment Project (CEAP). From 2011 to 2014, runoff samples were collected across three subdrainages representing two integrated BMPs and three subdrainages representing row crop cultivation. Best management practice sites studied were two vegetated drainage ditches (east [EDV] and west [WDV]) that subsequently flowed into a vegetated sedimentation pond (SP). A suite of critical water quality parameters were assessed and included total suspended solids (TSS), total phosphorus (TP), total nitrogen (TN), nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), and orthophosphate-phosphorus (PO4-P). During the four-year study period, integrated BMPs were effective at mitigating TSS runoff loads relative to row crop, but less effective at mitigating nutrient runoff loads. Runoff from WDV and SP were only moderately effective in mitigating nutrients in runoff with only TN and TP consistently reduced relative to row crop. Effectiveness of BMPs were primarily a result of the amount of area in tillage practices and crops planted relative to BMP within subdrainage basin area. Decreasing tillage:BMP and/or crop:BMP area ratios produced a subsequent decrease in runoff loads with the exception of NH4-N and PO4-P. [ABSTRACT FROM AUTHOR]

The article discusses the in-field best management practices (BMPs) to reduce the nutrient losses from agricultural fields with subsurface drainage.

This paper reviews the characteristics, benefits, and drawbacks of agricultural ditches and wetlands, as well as strategies for applying agricultural best management practices (BMPs) at the watershed scale for improving water quality. This synthesis focuses on the Great Lakes Region and the Mississippi River Basin in the United States, and specifically crop production systems in watersheds with subsurface drainage. The USDA Natural Resources Conservation Service (NRCS) has developed conservation practice standards for open channels and wetlands, which mitigate nutrient and sediment loading to surface water bodies from agricultural lands. Practices that use agricultural ditches to improve water quality, such as the two-stage ditch, have emerged in the last two decades and are starting to see a greater application in the region. Using wetlands as water treatment systems has a long history in a range of settings and over the past several decades is seeing more widespread application in agriculture. Water quality and watershed models are increasingly used to develop watershed strategies for reducing nutrient exports with agricultural BMPs. Models are also helpful in evaluating combinations of practices from the farm scale to the watershed scale. Application and limitations of several models commonly used in these regions of the United States are discussed. Finally, successful conservation strategies at the watershed scale must consider the human dimensions of watershed management, and we summarize the literature in this region on farmer perceptions and adoption of practices. [ABSTRACT FROM AUTHOR]

The article presents research on the best management practices (BMPs) perspectives as pollution control systems to improve the water environment in the U.S. An analysis of research trends through traditional bibliometric methods of certain fields mainly from publication output, geographical distribution and performance is outlined. The use of geographical information systems (GIS) in BMPs research with a stable frequency from 1994 to 2013 is also tackled.

A fall-planted winter cover crop is an agricultural management practice with multi-ple benefits that may include reducing nitrate (NO3) losses from artificial drained agricultural fields. While the practice is commonly used in the southern and eastern United States, little is known about its efficacy in midwestern states where winters are longer and colder, and artificial subsurface drainage is widely used in corn-soybean systems {Zea mays L -Glycine max L.).We used a field-tested version of the Root Zone Water Quality Model (RZWQM) to simulate the adoption of cereal rye (Secale cereale L.) as a winter cover crop and estimate its impact on NO3 losses from drained fields at 41 sites across the Midwest from 1961 to 2005. The average annual nitrogen (N) loss reduction from adding winter rye ranged from 11.7 to 31.8 kg N ha--1 (10.4 to 28.4 lb N ac-1) among four simulated systems. One of the simulated treatments was winter rye overseeded (aerial seeded) into a no-till corn-soybean rotation at simulated main crop maturity (CC2). On average, this treatment reduced simulated N loss in drainage by 20.1 kg N ha-1 (17.9 lb N ac-1) over the sites compared to systems without winter rye (NCC2), from 47.3 to 27.2 kg N ha-1 (42.2 to 24.3 lb N ac-1). Adding spring tillage to this treatment and killing the rye earlier (CC3) reduced simulated N loss from 57.3 (NCC3) to 34.4 kg N ha-1 (30.7 lb N ac-1). Replacing the corn-soybean rotation with continuous corn and spring tillage reduced simulated N loss from 106 (NCC4) to 74.2 kg N ha-1 (CC4) (94.6 to 66.2 lb N ac-1). Adding a winter rye cover crop reduced N loss more in the continuous corn system despite earlier spring termination of the winter rye and slightly less N uptake by the rye possibly because of more denitrification. Regression analysis of the RZWQM vari-ables from these sites showed that temperature and precipitation during winter rye growth, N fertilizer application rates to corn, and simulated corn yield account for greater than 95% of the simulated site-to-site variability in NO3 loss reductions in tile flow due to winter rye. Our results suggest that on average winter rye can reduce N loss in drainage 42.5% across the Midwest. Greater N loss reductions were estimated from adding winter rye at sites with warmer temperatures and less precipitation because of more cover crop growth and more soil N available for cover crop uptake. [ABSTRACT FROM AUTHOR]

The article focuses on the effort of the Minnesota Pollution Control Agency (MPCA) in developing statewide nutrient reduction strategy to reduce nitrogen (N) and phosphorus (P) loads in the Mississippi River. Topics discussed include excess of N and P in surface waters posing concern of toxicity to aquatic organisms locally and best management practices (BMP) such as reducing N rate in fertilizers, installing controlled drainage and restoring wetlands.

The article focuses on research on understanding what motivates farmers' conservation behaviors. Topics discussed include farmer behavior conceptualized as best management practices (BMP), use of the Long Term Ecological Research (LTER) Network created by the U.S. National Science Foundation to study farmers' conservation behaviors and improving the social, economic, and environmental sustainability of agricultural landscapes.

The article focuses on the management practices for phosphorus (P) loading, a primary contributor to surface water eutrophication in the U.S. Topics discussed include toxic effects of P in the surface water moved from soil to water or released over very long periods of time from high P source areas on the landscape and best management practice (BMP) such as P removal structure to decrease dissolved P loading in the short term.

Best Management Practices (BMPs) contribute to a broader range of efforts to improve the environmental performance of the livestock sector and its impact on water quality. This research evaluates a survey of cattle producers in an East Tennessee watershed and parts of five surrounding watersheds, along with and the factors correlated with preferences for BMPs designed to reduce sediment, nutrient, and fecal coliform contamination of surface waters by limiting cattle access to streams. The objective of the survey was to gather behavioral information about producer interest in specific BMPs in an effort to supplement a long-term biophysical modeling project. Structures and BMPs analyzed include stream crossings, rotational grazing, pasture improvement, and cattle water tanks. The physical and economic constraints faced by producers and the incentives provided by state and federal programs influence the decision to adopt a set of practices or structures that impact pathogen loading into streams. There was a clear preference for a suite of BMPs that did not include stream crossings, reinforcing anecdotal evidence that the maintenance associated with frequent high flow events may reduce willingness to install stream crossings. Cattle producers were more willing to implement rotational grazing and pasture improvement BMPs, which were associated with cattle health and productivity. The extensive distribution of pasture-land in the region analyzed, the relatively inexpensive costs of adopting practices supporting pasture improvement, and higher quality forage correlated with improved pastures suggest a win-win outcome for cattle owners and efforts to enhance water quality. [ABSTRACT FROM AUTHOR]

In the state of Delaware, approximately 50% of the rivers have total phosphorus (P) concentrations greater than 0.1 mg L-1, the concentration above which freshwater bodies are considered impaired by P. The structural best management practice commonly recom- menddd by advisory agencies to control nonpoint P loss is the vegetated filter strip (VFS). In the Coastal Plain region of Delaware, where P saturated soils are commonly found, VFS should trap particulate P, but their effectiveness at preventing dissolved P losses is less certain. The objectives of this research were (1) to develop a rapid soil test to determine ifaVES has the potential to adequately mitigate dissolved P in agricultural runoff at a designated site and (2) to deternune, in laboratory tillage simulation studies, if deep tillage prior toVFS planting can improve dissolved P retention within VFS. Soil samples were collected from existing VFS and adjacent fields, as well as from field margins where new VFS were to be planted, and were characterized for organic matter, water pH, water soluble P Mehlich 3 extractable elements (P, Al, and Fe), and Mehlich 3 P Saturation ratio (M3-PSR). A subset of soils was selected to characterize P sorption and desorption properties of the VFS, including total P sorption capacity (PSCr), remaining P sorption capacity (PSC), and the equilibrium P concentration at zero sorption (EPC0). Both the ratio of PSCr to PSCt (an estimate of the percentage of remaining P sorption capacity) and EPC0 were well correlated with M3-PSR (r2 0.92,0.93). Simulated deep tillage decreased M3-P by 62% compared with surface soils and decreased PSR by as much as 70%. Study results suggest that the M3-PSR soil test can lead to a bet- ter understanding of whether a VFS installed at a particular site can be expected to retain dissolved P in agricultural runoff. Likewise, M3-PSR can also be used to determine if deep tillage prior toVFS installation will be beneficial for overall dissolved P management. [ABSTRACT FROM AUTHOR]

The effectiveness of best management practices (BMPs) designed primarily to protect surface water quality was assessed on a farm certified for organic tomato production to consider potential environmental quality and production tradeoffs. The BMPs included winter cover crops typically used in organic farming to cycle nutrients and reduce stormwater runoff; tailwater ponds designed to capture runoff; and tailwater return systems, which recycle runoff back to the field. The study took place at a 44 ha (108 ac) farm inYolo County, California, over a two-year period. Monitoring throughout the winter rainy season showed cover crops successfully reduced runoff and loads of several constituents during the storm events, when compared to fallow. Total discharge was reduced by 44%, total suspended solids was reduced by 83%, ammonium was reduced by 33%, and dissolved organic carbon (DOC) was reduced by 58%. Estimates of leaching losses of DOC in the cover cropped fields, however, were 70% higher than the fallow fields in the winter rainy season and were 30% higher than the fallow fields in the summer irrigation season. During the summer irrigation season, the tailwater pond alone was highly effective in reducing losses of total suspended solids and volatile suspended solids to the neighboring riparian zone by 97% and 89%, respectively The tailwater pond had no effect on dissolved reactive phosphorous and actually increased concentrations of nitrate-nitrogen (NO3--N) in effluent by 40% and DOC by 20%. As was expected, the NO3--N leaching measured by anion exchange resin bags and nitrous oxide emissions measured by static closed chambers was higher for the tailwater pond than the fallow field. Despite these differences, losses via NO3--N leaching and nitrous oxide emissions accounted for only 24.7 and 0.48 kg N ha-1 y-1 (22.0 and 0.40 lb N ac-1), respectively, for the entire farm, even including ponds and ditches. When field and plot values were extrapolated to the entire tomato production area to understand the relative potential tradeoffs, results indicate that BMPs could be implemented without an impact on tomato marketable yields; the tallwater pond's higher nitrous oxide emissions would not significantly increase the overall emissions for tomato production given its relatively small size; and using tailwater ponds in combination with cover crops would decrease total suspended solids (TSS) losses compared to cover crops alone, with only minor increases in NO3--N and DOC losses. Adding a tailwater return system to this combination of BMPs could help minimize these NO3--N and DOC losses. Use of cover crops with a tailwater pond and tailwater return system are a combination of BMPS that can thus be recommended for organic production when considering multiple environmental outcomes. [ABSTRACT FROM AUTHOR]

The nonpoint source pollution problem can be controlled by implementing various best management practices (BMPs) in the watershed. However, before such practices are adopted, their effectiveness at various spatial and temporal scales must be evaluated. The objective of this research was to evaluate a suite of BMPs in a pasture-dominated watershed in their effectiveness at controlling nutrient losses. A total of 171 different BMP combinations incorporating grazing and pasture management, riparian and buffer zones, and poultry litter applications were evaluated for their effectiveness using the Soil and Water Assessment Tool (SWAT) model. The SWAT model was parameterized using detailed farm and watershed-scale data. The stochasticity in weather was captured by generating 250 various possible weather realizations for a 25-year period, using measured historical climate data for the watershed. Model results indicated that losses of both total nitrogen, mineral phosphorus, and total phosphorus increased with an increase in litter application rates. For the same application rates, greatest losses were predicted for fall application timings compared to spring and summer applications. Overgrazing resulted in greater nutrient losses compared to baseline conditions for all application rates, timings, and litter characteristics, indicating that overgrazing of pasture areas must be avoided if any improvement in the water quality is to be expected. Variability in weather conditions significantly affected BMP performance; under certain weather conditions, an increase in pollutant losses can be greater than reductions due to BMPs implemented in the watershed. Buffer strips and grazing management were two most important BMPs affecting the losses of total nitrogen and total phosphorus from the pasture areas. [ABSTRACT FROM AUTHOR]

There is growing interest in evaluating the impacts at the watershed scale of agricultural best management practices (BMPs) designed to improve water quality. Many approaches to impact assessment require detailed information about actual BMP use by farmers and landowners in a watershed. This paper examines the strengths and weaknesses of using formal USDA Natural Resources Conservation Service records of conservation program participation as an indicator of spatial and temporal patterns of BMP implementation and maintenance. Field interviews with conservation program participants revealed potential limitations with official records regarding (1) documentation of the incidence of successful BMP implementation, (2) the nature of the BMPs that were implemented, (3) accurate measurement of the timing and location of BMP implementations, and (4) information about the long-term use and maintenance of implemented BMPs. The results suggest that official records should be field-verified before being used as indicators of BMP use. The findings also point to a larger need for development of more robust and accurate systems for tracking BMP implementation and maintenance over periods of time. [ABSTRACT FROM AUTHOR]

Near-stream best management practices (BMPs), such as exclusionary fencing or cattle crossings, are often recommended to improve water quality, but quantification of their impacts is limited. Surface and subsurface processes in these near-stream areas impact the contribution of nitrogen and phosphorus to watercourses and the effectiveness of near-stream BMPs. To test the impact of the near-stream BMPs, groundwater samples from 30 piezometers and streamwater samples along two adjacent creeks (one control and one with BMP treatment) were collected over a three-year period before and after installation of exclusionary fencing with a cattle crossing in the Catskill Mountains of New York State. Samples were analyzed for nitrate nitrogen (NO3--N), soluble reactive phosphorus (SRP), dissolved oxygen, and dissolved organic carbon. Analysis results and other ancillary variables (rainfall and groundwater table depth) were incorporated into a multivariate statistical model to evaluate the impact of the BMPs on the concentrations of NO3--N and SRP in the treatment creek. Results of the analysis indicate that the installation of the near-stream BMPs resulted in a 27% yearly (34% during the growing season) reduction in treatment creek SRP concentrations, while there was little impact on NO3--N concentrations. Incorporating the SRP concentrations measured in a nearby control creek and controlling for the effects of groundwater SRP levels and groundwater hydrology (water table height) had a significant effect on the overall analytical model performance. These results indicate that protecting near-stream areas from potentially pollution-causing practices can be an important means of controlling phosphorus levels in water bodies. [ABSTRACT FROM AUTHOR]

A study was conducted to quantify land use and management changes and their effects on water quality as part of an effort to evaluate the effects of best management practices under the Conservation Effects Assessment Project. This study was focused on the Lincoln Lake watershed, a primarily pastured watershed in northwest Arkansas and one of the watersheds funded under the Conservation Effects Assessment Project competitive grants program. As with a number of other Conservation Effects Assessment Project watersheds, this watershed has undergone substantial land-use change over the past few years. These changes have occurred concurrently with best management practice implementation. Thus, the need has arisen to determine their impacts on watershed water quality. Land-use analyses covering a 12-year period revealed a rapidly changing landscape, with the various land uses experiencing gains and losses at different times. Furthermore, a systematic trend for pastured areas to be replaced by urban land uses was identified, with pastures experiencing a net decline of about 12% during the analyses period. With regard to water quality downward trends were observed under base and storm flow conditions in the upper reaches (Upper Moores Creek) with significant changes in total phosphorus and total suspended solids (p-valpes = 0.0153 and 0.0135,respectively). Significant increases in flow and nitrate-nitrogen (p-values = 0.0465 and 0.0927, respectively) were observed in the lower reaches (Lower Moores Creek), while no appreciable changes were observed in one part of the watershed. We conclude that the concurrent implementation of best management practices served to protect water quality from otherwise adverse effects that might have occurred due to a rapid urbanization in the watershed. [ABSTRACT FROM AUTHOR]

Increased awareness of the contributions of non point source runoff to the degradation of water quality in the Mississippi River and Gulf of Mexico emphasizes the need to increase conservation practices that reduce nutrient export from agricultural lands. To achieve long- term conservation goals in agricultural landscapes, it is important to understand farmers' perspectives on what practices are effective, practical, and economically attainable. We conducted a series of surveys, interspersed with focused outreach, of farmers in two agricultural watersheds in central Illinois in an attempt to better understand how outreach influenced their views on and adoption of conservation practices. Programs differed between the two watersheds in terms of the levels of intensity at which outreach efforts were conducted. Survey results suggest that more intensive outreach efforts, such as one- on-one landowner visits, localized workshops, and tours, can increase adoption of conservation practices associated with cost-share programs. Technical and financial assistance provided in a timely manner that did not interfere with planting and harvesting were major incentives among farmers in both watersheds to participate in cosi-share conservation programs. Primary disincentives among farmers to enroll in cost-share programs were associated with multiple programmatic changes and complex application processes. Results indicate that there remains a need for outreach that increases awareness and implementation of conservation and best management practices specific to reducing agricultural runoff from tile-drained sources. Mitigation of non point runoff will also require more effective management of nitrogen application rates and timing in order to conserve freshwater resources in Midwest agricultural landscapes and downstream waters. Integrated outreach teams comprised of stakeholder's and local conservation agencies may lead to successful outreach efforts and reduce demands on limited conservation agency staff time. [ABSTRACT FROM AUTHOR]

The article focuses the issues related on the use of performance-based incentives to control agricultural pollution. It states that performance-based incentives are used to improve environmental quality, farm income, and motivator for farmers to minimize pollution. It highlights the development of incentive mechanisms to enhance environmental conservation and control contributor of nonpoint source (NPS) pollution. It presents the aim of Performance-based Environmental Policies for Agriculture (PEPA) to create a link between economic theory and NPS pollution control programs by implementing performance-based incentives. It also features the use of Phosphorus Index in the Missisquoi River watershed of northwestern Vermont.

The Choptank River is an estuary, tributary of the Chesapeake Bay, and an ecosystem in decline due partly to excessive nutrient and sediment loads from agriculture. The Conservation Effects Assessment Project for the Choptank. River watershed was established to evaluate the effectiveness of conservation practices on water quality within this watershed. Several measurement frameworks are being used to assess conservation practices. Nutrients (nitrogen and phosphorus) and herbicides (atrazine and metolachlor) are monitored within 15 small, agricultural subwatersheds and periodically in the lower portions of the river estuary. Initial results indicate that land use within these subwatersheds is a major determinant of nutrient concentration in streams. In addition, the 18O isotope signature of nitrate was used to provide a landscape assessment of denitrification processes in the presence of the variable land use. Herbicide concentrations were not correlated to land use, suggesting that herbicide delivery to the streams is influenced by other factors and/or processes. Remote sensing technologies have been used to scale point measurements of best management practice effectiveness from field to subwatershed and watershed scales. Optical. satellite (SPOT-5) data and ground-level measurements have been shown to be effective for monitoring nutrient uptake by winter cover crops in fields with a wide range of management practices. Synthetic Aperture Radar (RADARSAT-1) data have been shown to detect and to characterize accurately the hydrology (hydroperiod) of forested wetlands at landscape and watershed scales. These multiple approaches are providing actual data for assessment of conservation practices and to help producers, natural resource managers, and policy makers maintain agricultural production while protecting this unique estuary. [ABSTRACT FROM AUTHOR]

The project team was successful in gaining voluntary stakeholder participation in the effort to evaluate the effectiveness of best management practices at reducing sediment and nutrient runoff and the factors that influence the adoption of best management practices by farmers. The Lincoln Lake watershed, a primarily agricultural subbasin of the politically embattled Illinois River watershed, lies within a designated nutrient surplus area of the state of Arkansas. The team initially faced a watershed population whose trust needed to be gained before any progress could be made. Successful stakeholder participation was fostered through the use of techniques taught to and used by extension agents of the University of Arkansas Division of Agriculture Cooperative Extension Service. The results of this stakeholder-guided collaborative approach allowed the collection of high-quality farm data, perceptions of stakeholders regarding water quality, and reasons why farmers adopt or refuse to adopt best management practices. [ABSTRACT FROM AUTHOR]

This article reviews 25 years of literature focused on the adoption of agricultural best management practices (BMPs) in the United States to examine general trends in the categories of capacity, awareness, attitudes and farm characteristics, The study uses a vote count methodology and counts every instance of positive, negative and insignificant relationships in 55 studies. Education levels, capital, income, farm size, access to information, positive environmental attitudes, environmental awareness, and utilization of social networks emerge as some of the variables that are more often positively, rather than negatively, associated with adoption rates. The type of statistical analysis used in the studies has a negligible effect on the results. When different types of BMPs are examined in similar groupings, the aggregated findings generally hold true. The study concludes that farmer adoption rates can be improved by focusing on the generally consistent determinants of agricultural BMP adoption. This paper also highlights future areas of research that are needed including a focus on the determinants of adoption of water and livestock management BMPs and more study of the role of tenure and farm proximity to a river or stream. [ABSTRACT FROM AUTHOR]

We evaluated the effectiveness of three best management practices for fluecured tobacco production--reduced tillage, grassed field-side filter zones, and forested filter zones--to determine the total reduction in suspended solids from storm water runoff. Use of reduced tillage in comparison with conventional tillage decreased total suspended solids leaving tobacco fields by 82%. Grassed field-side filter zones functioned very well in retaining solids in early summer but were overloaded by late summer. Forested filter zones were able to back up the grassed filter zones when they overloaded and exported total suspended solids to the forested filter zones. In combination, grassed filter zones and forested filter zones retained 68% to 69% of total suspended solids, respectively. Dense vegetation in the cutover forested filter zone more than doubled its capacity to detain solids, compared to the same forested filter zone when it was covered by mature mixed pine-hardwood. Use of these best management practices in series can significantly reduce sediment loss from tobacco; however, use of reduced-till may reduce tobacco yield and quality. [ABSTRACT FROM AUTHOR]

The effectiveness of best management practices (BMPs) at preventing erosion and controlling storm water and sediment runoff in developing catchments in the Reedy River (South Carolina) watershed was evaluated from 2004 to 2005. Catchment-normalized storm Water runoff and event mean concentrations and cumulative mass loads of selected pollutants were compared among four catchments exhibiting similar rainfall, soil, and geographic characteristics but undergoing varying degrees of development. Despite the implementation of BMPs, streams below catchments undergoing active development exhibited patterns characteristic of urbanized watersheds, namely, storm hydrographs characterized by steep rising and descending limbs due to accelerated storm water runoff. In contrast with the developing catchments, streams below relatively undisturbed catchments exhibited more gradual rising and descending limbs on their hydrographs, presumably due to enhanced infiltration and interflow and less direct surface runoff. A comparison of surface runoff depths and runoff ratios confirmed more direct surface runoff was generated from rainfall in the developing catchments versus the undisturbed catchments despite the use of BMPs. In addition, area-normalized maximum stream discharges during storm events were generally higher for the developing versus undisturbed catchments. Similarly, mean concentrations and mass loads of total suspended solids were consistently higher for the developing versus undisturbed catchments. In many cases, mean concentrations for total suspended solids and other selected pollutants in storm water runoff from the developing catchments exceeded recognized water quality criteria. Taken together, the quantity and quality of storm water runoff from the developing catchments indicate that the overall protective goals of erosion prevention and sediment control regulations are not being met. Possible explanations for this include BMPs that have not been properly designed or located, are not the correct type, are insufficiently numerous, and/or have not been adequately maintained to control the increased surface runoff and/or soil erosion due to land disturbance. Alternatively, the failure may reflect shortcomings in the regulations themselves. [ABSTRACT FROM AUTHOR]

Conservation tillage is a well known best management practice that improves soil quality, reduces runoff and erosion, and increases infiltration. However, a rapid assessment strategy for quantifying the rate and spatial distribution of conservation tillage practices is lacking. This study was designed to evaluate the sensitivity of a remotely derived crop residue cover index for depicting conventional tillage (CT), strip tillage (ST), and no-tillage (NT). systems in a cotton-corn-peanut rotation in tile southeastern Coastal Plain. Treatments consisted of CT (rip and bed operation), NT, NT with subsoiling, and STE. Remotely sensed data were acquired three times prior to canopy closure, using a handheld multispectral radiometer (485 to 1,650 nm) and thermal imager (7,000 to 14,000 nm). Using a combination of visible and near-infrared spectra, a crop residue cover index was calculated and evaluated. Results showed that crop residue cover is greatest in years, planted with peanut or cotton--likely due to the later winter cover crop termination date compared to years when corn is planted. The. crop residue cover index outperformed the thermal infrared, accurately separating conventional from conservation tillage treatments in four out of six data acquisitions in 2004 and 2006. Differentiation among conservation tillage treatments was inconsistent. Regression analyses showed that a strong linear relationship existed between tile crop residue cover index and measured crop residue cover (r² = 0.51 to 0.86, alpha = 0.10).These data suggest that remotely sensed data may be used as a rapid, field-scale indicator of conservation tillage adoption. Rapid assessment methodologies are necessary to quantify the impact of conservation practice adoption on Water quality/quantity, assess adoption rates, and improve the placement of conservation tillage practices at local, watershed and regional scales. [ABSTRACT FROM AUTHOR]

Over the past few decades many millions of dollars have been spent on the promotion, installation, and maintenance of cropland best management practices (BMPs) that reduce nutrient and sediment runoff. Compensating producers through conservation programs for BMP adoption has had notable success to date; however, there are still many producers who choose not to participate in conservation programs and/ or decide not to implement BMPs. Why is this the case and how can we as conservationists better promote and encourage BMP adoption and conservation program participation? We found that a high percentage of producers are aware of available conservation programs; however, less than half of those indicate that they have participated in the programs. Our survey results suggest there is no single, simple answer to speeding the rate of producers' BMP adoption and participation in conservation programs. We advocate that participation rates can be raised substantially through a multifaceted approach that may include increased payment levels but also acknowledges the gap in perceptions, provides more flexible enrollment options, and simplifies enrollment procedures and rules while continuing to ensure compliance. [ABSTRACT FROM AUTHOR]

This paper presents case studies with two-stage channel geometries that were sized based on geomorphic principles. Geomorphic data were collected at the project site and throughout the watershed. Watershed specific regional curves were developed for each project. Factors considered in sizing each system were the widths and depths of the inset channels that were associated with the channel forming discharge, bench widths, and the side slopes of the banks of the second stage. The channel-forming discharges for the inset channels corresponded with appropriate recurrence intervals for the region. The approach leaves the preconstruction inset channel intact and constructs, or widens, benches at elevations consistent with channel-forming and regional curve concepts. Two-stage channel system construction was discovered to he easier than clean out operations for traditional trapezoidal channel maintenance. Overall, two-stage channel projects cost more than traditional channel maintenance, but they have an anticipated improved design life. Since construction, cross-section surveys were periodically made for two case studies. No elevation changes were found in the benches, but the inset channels have narrowed. [ABSTRACT FROM AUTHOR]

Outlined is a practical approach to size and modify agricultural drainage channels to two-stage geometry to maintain drainage function and capacity while increasing channel stability. Two-stage channel systems consist of an inset channel and small floodplain (benches) within the ditch confines. The two-stage channel sizing procedure includes nine steps: (1) project identification; (2) data collection; (3) data analysis; (4) hydrologic evaluation; (5) conceptual channel system sizing; (6) project assessment; (7) design and/or final sizing; (8) construction; and (9) monitoring and assessment of performance. Channel width and depth dimensions are determined based on a weight-of-evidence approach that considers geomorphology measurements at the project site and throughout the watershed. The authors have developed spreadsheet tools to aid in evaluating the geomorphology of one and two-stage channels. Constructing a two-stage channel requires more excavation than traditional ditch maintenance, but benefits include improved conveyance capacity, a channel geometry that will be more self-sustaining, and improvement to in-stream habitat. [ABSTRACT FROM AUTHOR]

Nonpoint source pollution in intensively managed agricultural landscapes is of great concern to the general population, farmers and policymakers, as it impacts local water quality and can have large downstream effects, as in the case of hypoxia in the Gulf of Mexico. In this study, we outline a methodology to simultaneously assess economic costs and water quality benefits associated with the hypothetical placement of a broad set of conservation practices. The study, performed for the Iowa Department of Natural Resources, assesses thirteen major subbasins in Iowa by interfacing economic models with the Soil and Water Assessment Tool model. The conservation practices analyzed include land set-aside, terraces, grassed waterways, contouring, conservation tillage, and a simple nutrient reduction strategy. Annual costs range from $300 to $597 million. Predicted sediment, total phosphorus (P), and nitrate decreases range from six to 65 percent, 28 to 59 percent, and six to 20 percent, respectively, relative to the baseline. [ABSTRACT FROM AUTHOR]

Evaluates the best management practice (BMP), program to reduce surface runoffs, to the setback requirement around standpipes or surface inlets in a tile-outlet terraced field. Effects of establishing drinking water standards and concerns for the quality of surface water resources; How surface run-off into and out of temporary storage were monitored; Percent herbicide losses from terraces in 1983.

The article reports on the Mexican Decision Support (MEDS) project, a national effort proposed by the National Council of Science and Technology of Mexico to prioritize water resources research on watersheds in Mexico. Mexico's MEDS is similar to the Conservation Effects Assessment Project (CEAP) of the United States and to the Watershed Evaluation of Beneficial Management Practices (WEBs) project of Canada. It aims to develop a quantitative measurement for recognizing watershed problems among farmers. It would include watersheds with a process or regional problem and located within natural protected areas of the National Commission for Knowledge and Protection of the Biodiversity.

The article discusses a study which aimed to determine whether best management practices (BMP) implemented in a study catchments undergoing active development in the upper Piedmont physiographic region of South Carolina are adequately protective of downstream aquatic environments. Runoff characteristics and pollutant concentrations and loadings in storm water runoff from four catchments with varying degrees of land disturbance activities were compared in this study. Two complementary approaches were used to evaluate BMP performance at development sites on a comprehensive catchment-scale basis with respect to maintaining water quantity and quality in receiving streams.

The article presents a study on what motivates farmers to embrace best management practices (BMPs). It states that in an effort to understand the reason behind the farmers' adoption of BMPs, the authors conducted a meta-analysis of all the relevant literature in the U.S. They discovered that there are no factors that consistently identify BMP adoption, but there are some variables that generally drift toward having a substantial impact on adoption rates. Access to information, awareness, and social networks are all found to be relevant and have a positive correlation with farmers' BMP adoption.

The article focuses on the a study on the effects of best management practices (BMPs) on water quality and response times between small watersheds and medium-sized watersheds, which was analyzed using the data from the North Appalachian Experimental Watershed in Coshocton, Ohio. It states that on the hydrologic systems evaluated, once the groundwater discharge emerged on the land surface below the small watersheds, it quickly entered or produced perennial streams in the medium watersheds of which they were part of. Thus, the nitrate-nitrogen concentration patterns observed from pasture systems, were soon observed in the stream base flow.

The article discusses findings of a study which evaluated a combination of best management practices used on two agricultural watersheds in North Carolina. The research is aimed at estimating the combined reductions that can be achieved for tobacco cultivation. A significant source of pollutants to surface water is the storm runoff from agricultural fields. The three best management practices for flue-cured tobacco production include reduced-till versus conventional tillage, grassed field-side filter zones and forested filter zones.

The article considers the use of compost to improve vegetation and limit erosion on mountain road cuts. Mountain road cuts frequently suffer from large-scale soil erosion because soils from decomposed granite are generally thin. Attempts have been made to quantify the amount of sediment lost from road cuts in areas such as Lake Tahoe, California. Researchers tried to quantify erosion from ambient and compost-amended treatments on a decomposed granite slope. After constructing test plots at the base of a severely eroded slope and incorporating waste compost, the researchers found that very little erosion was noticeable. The author believes that quantifying the ability of best management practices to lessen erosion is needed in order to facilitate the use of mountainous areas.

Best management practices (BMPs) are a critical tool for preventing or mitigating the degradation of water quality caused by soil erosion. However, currently available assessment models are primarily designed for use over and, therefore, are only valid over these particular spatial and temporal scales. This study investigates the feasibility of combining three models that were designed for use at different spatial scale into a single assessment tool that allows for more detailed, spatially-explicit assessment of BMPs over both short (four to eight years) and longer (100 year) time scale. The three models evaluated were: 1) the Water Erosion Prediction Project (WEPP) model for hillslope and small watershed up to 260 ha (642 ac); 2) the Geospatial interface for WEPP (GeoWEPP), which utilizes geographic information system (GIS) or precision farming datasets of topography, soils, and landuse to automatically derive WEPP model input; and 3) a linked GeoWEPP-SWAT model, which injected WEPP model output as point sources into the Soil and Water Assessment Tool (SWAT). The linked GeoWEPP-SWAT model provides a mechanism for applying the WEPP model to larger watershed scales beyond the validity of its channel routing algorithms. This paper summarizes the challenges, validity, and opportunities of this modeling approach for BMP assessment in large watersheds. [ABSTRACT FROM AUTHOR]

Phosphorus (P) losses from irrigated cropland transferred to surface waters via irrigation return flows, can impair regional water quality. Best management practices to reduce soil erosion on fields and sediment concentration in return flows do little to reduce soluble P concentrations, which can exceed total maximum daily load (TMDL) limits for total P. Laboratory and field tests were conducted to evaluate the effect of alum on soluble P concentration in return flow water from an irrigation tract in southern Idaho. The laboratory study used two water sources (tap and irrigation), three sediment concentrations (0, 100 and 1000 mg L-1), two added P concentrations (0 and 1 mg L-1), and five alum concentrations (0, 5, 10, 20 and 40 mg L-1). Field tests were conducted at sediment ponds on two irrigation drains with 20 to 500 mg L-1 sediment and 0.09 to 0.19 mg L-1 dissolved P in inflow water. Regression analysis of laboratory data showed a 53 percent reduction in soluble P concentration with 20 mg L-1 alum, which was similar to field data. Applying 40 mg L-1 alum to irrigation water reduced soluble P concentrations up to 98 percent in the field. Achieving 50 percent soluble P reduction would cost about $0.007 m-3 ($8.25 per ac ft) at the current alum cost of $0.33 kg-1 ($0.15 lb-1). Although alum effectively reduced soluble P in irrigation return flow, the cost of applying alum may be too high for routine use in many irrigation districts. [ABSTRACT FROM AUTHOR]

Factors affecting cattle producersâ €™ adoption of best management practices (BMPs) are examined using probit analyses. Results show that in situations such as when the farm includes more enterprises, the farmer has had contact with Natural Resources Conservation Service personnel at least once within the past year, the farmer holds a college bachelor’s degree, the percentage of income from beef cattle production is higher, or the operation includes hilly land, the likelihood of BMP adoption is greater. Having a greater number of other agricultural enterprises and having a greater percentage of income from the cattle operation were significant factors in the adoption of companion practices. Results of this study suggest changes in formulating future environmental policies associated with pasture-based beef cattle production. [ABSTRACT FROM AUTHOR]

A best management practice (BMP) tool was developed as a part of an effort to address the phosphorus (P) pollution and associated eutrophication problem affecting the Cannonsville Reservoir, part of the New York City water supply system. P reaching the reservoir is thought to emanate from runoff from the surrounding farms, mainly as a result of manure spread on these farms. Efforts to address the problem have involved implementation of BMPs on the watersheds; however, the effectiveness of these practices is not known. This study establishes a means of estimating BMP effectiveness, based on data available in the literature, and develops a tool that allows users to obtain BMP effectiveness estimates for their respective site soil and slope conditions. The tool offers stand-alone capabilities and has the potential to be linked to a GIS. An example is presented to illustrate tool application for effectiveness-based BMP selection, with a focus on a farm within the New York City watersheds. [ABSTRACT FROM AUTHOR]

Millions of dollars have been spent on agricultural watershed projects across the nation, but little is known about the long-term impacts of watershed management and protection efforts. Information pertaining to long-term condition and water quality impact of best management practices (BMPs) is scarce. Evaluation methods that estimate the current condition of the practice based on visual inspection and comparison to selected original design dimensions were developed for grassed waterways, grade stabilization structures, field borders and parallel terraces. The evaluation tools were tested for validity using an expert panel approach and for reliability based on inter-rater correlation. The evaluation tool's three-point scale rating system assigns a score of three to a BMP that was fully functional and still met its original design purpose and a score of one to a BMP that no longer performed as designed. The newly developed evaluation tools were applied to a subset of structural BMPs implemented in the late 1970s in a major watershed management project in an Indiana watershed. One-third of the BMPs no longer remain. Those BMPs that remain today are in fair condition and are reasonably functional. Grassed waterways and terraces were most likely to remain, while the field borders that still existed had the highest condition score. This study suggests that BMPs can in some cases continue to function past their design life, but serves as a reminder that BMP functional life is limited, a fact that needs to be explicitly considered in conservation and watershed planning. [ABSTRACT FROM AUTHOR]

Best management practices (BMPs) are promoted to reduce water pollution from agricultural activities. This study investigates the likely determinants of Louisiana dairy farmers' decisions to voluntarily implement BMPs. Adoption rates of 21 BMPs ranged from 28 to 83 percent, with "not applicable to my farm" as the most often cited reason for non-adoption. Larger, more productive farms with greater financial resources were the most frequent adopters of BMPs. Use of sources of information such as seminars and the Cooperative Extension Service were associated with greater adoption, underscoring the importance of information in encouraging adoption. Younger, more educated farmers who had been in business a shorter time, as well as those who had a family member planning to take over the farm upon the farmer's retirement were more likely to adopt BMPs. [ABSTRACT FROM AUTHOR]

A community-based adaptive management framework is applied to the Calapooya Creek, Deer Creek, and Myrtle Creek watersheds within the Umpqua River Basin in Southwestern Oregon. The objectives are to: 1) identify agricultural landowner participation in watershed conservation projects, and 2) determine the characteristics of participating and non-participating landowners. Data is derived from a 1998 landowner mail survey with a 53% response rate. Landowners implement upland conservation practices such as off-stream livestock water developments and rotational grazing more often than riparian fencing, riparian tree planting, and installing fish screens on irrigation diversions. The key factors in adoption of conservation practices include the use of irrigation, shared management decisions with a spouse, a belief in scientific experimentation, and discussion of conservation with others. The key factors predicting adoption of best management practices depended on the kind of best management practice implemented. [ABSTRACT FROM AUTHOR]

Riparian buffers and constructed wetlands are best management practices (BMPs) that can improve water quality. However, these practices are not equally effective in all locations. Our objective was to develop maps to help plan the placement of BMPs in a watershed for water quality benefits. Tipton Creek, a 49,000-acre Iowa watershed, provided a case study. Buffer-placement maps, developed from analysis of 30-m (100-ft) elevation data, identified riparian locations with large wetness indices, where buffer vegetation could intercept sheet/rill flows from significant upslope areas. These sites were numerous, typically small (<200 m in length) and well distributed spatially. However results showed 57% of riparian grid-cells would receive runoff from less than 0.4 ha (1 ac). Candidate wetland sites were also mapped by applying interpretive and automated techniques to terrain analyses results. A team of conservation professionals evaluated the planning utility of these maps in the field through consensus-seeking discussion. Buffer maps highlighted areas where, team members agreed, perennial vegetation could effectively intercept runoff and/or manage seasonal wetness. The review team also located three feasible wetland sites, which were all identified by an automated technique showing 12 candidate sites. The methods only required public data and should be applicable to other watersheds. [ABSTRACT FROM AUTHOR]

Management practices may affect the potential for nitrate leaching from agricultural systems. Two studies are discussed that used plot-size lysimeters on loamy sand and clay loam soil in Northern New York. One was conducted from 1991 to 1994 and involved sod plowing and the use of three rates of fertilizer on maize (Zea mays L.). The other study was conducted from 1997 to 2000 and quantified N-leaching losses under maize and orchardgrass (Dactylis glomerata L.) as affected by the timing of manure application. These studies showed that timing and rate of N fertilizer and manure additions, timing of green-manure incorporation, and soil type strongly influenced N-leaching losses. Losses from fall-applied N sources were high, especially on coarse-textured soils. Lower N losses in fine-textured soils were primarily the result of higher denitrification losses, rather than reduced percolation rates. It was concluded that the current N Leaching Index ignores important processes and requires a more dynamic approach that includes management factors. In the interim, we established a set of best management practices for N to reduce the potential for N leaching losses. [ABSTRACT FROM AUTHOR]

Modeling phosphorus (P) loss from agricultural watersheds is key to quantifying the long term water quality benefits of alternative best management practices. Scientists engaged in this endeavor struggle to represent processes controlling P transport at scales and time frames that are meaningful to farmers, resource managers, and policy makers. To help overcome these challenges, we reviewed salient issues facing scientists that model P transport, providing a conceptual framework from which process-based P transport models might be evaluated. Recent advances in quantifying the release of soil P to overland and subsurface flow show that extraction coefficients relating soil and flow P are variable but can be represented as a function of land cover or erosion. Existing information on best management effects on P export should be linked to watershed models to better represent changes in P transport. The main needs of P transport models are inclusion of flexible coefficients relating soil and overland flow P, fertilizer and manure management and P loss, stream channel effects on edge-of-field P losses prior to water body input, and linkage of watershed and water-body response models. However, it is essential that the most appropriate model be carefully selected, according to a user's needs in terms of available input data, level of predictive accuracy, and scale of simulation being considered. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is an important input for economic crop and livestock production systems. Excessive losses of P from agricultural systems to surface waters can accelerate eutrophication and degrade water quality. This paper reviews the behavior of P in agricultural soils and discusses the transport of P from land to water. The forms, measurement, and sorption processes of P in both soil and water are discussed. Soil test P, the most common soil P analysis, is described relative to other forms of soil P and its use for agricultural and environmental purposes is explained. Loss of soil P to water can occur in particulate forms with eroded surface soil and in soluble forms in runoff, soil interflow, and deep leaching. This paper discusses the relative importance of each transport pathway as affected by soil type and management. Soil P dynamics and water quality risks associated with fertilizer and manure application are illustrated with several examples. Finally, the paper reviews management practices that can effectively reduce the loss of agricultural P to surface waters. [ABSTRACT FROM AUTHOR]

Sediment has been identified as the pollutant most limiting to fishery health in oxbow lakes in the Mississippi Delta. The Mississippi Delta Management System Evaluation Area (MDMSEA) project seeks to reduce the adverse agricultural impacts on water resources and ecological processes through the development and adoption of alternative best management practices (BMPs). However, resource limitations dictate that only a few combinations of BMPs can actually be physically tested over a few years at a limited number of locations. To extend results and better evaluate the effectiveness of alternative BMP combinations on sediment reduction, the Annualized Agricultural Nonpoint Source pollutant loading model (AnnAGNPS 2.1) was applied to a 12 ha (30 ac) MDMSEA subwatershed. BMPs considered included cover crops, filter strips, grade control pipes, and impoundments. Each BMP was considered in combination with three tillage systems: conventional tillage, reduced tillage, and no-till. Costs of BMPs were estimated using 2001 state average prices for Mississippi. Amortized fixed costs, using a 25 yr planning horizon and interest rates of both 5% and 10%, were combined with direct annual costs into total annual cost estimates. AnnAGNPS predicted that no-till alone, reduced tillage with winter cover and an edge-of-field pipe, or conventional tillage with a small permanent impoundment (covering less than 3% of the watershed) would all reduce sediment yield by at least 50%. The most cost-effective BMPs were management of volunteer winter weeds as cover crops and various types of edge-of-field grade-control pipes. The average marginal cost using BMPs for sediment yield reduction was about $8 MT-1 ($7.3 t-1) for conventional and reduced tillage. The cost was higher, about $10.7 MT-1, ($9.7 t-1) for no-till because the practice of no-till alone reduced sediment yield by half, and further marginal reductions were more expensive. [ABSTRACT FROM AUTHOR]

This paper shows how farm economics information that is widely available can be used to help guide local resource managers and watershed groups in their efforts to design cost-effective programs to improve water quality. The focus is on the economic elements driving farmer and landowner decisions and how those compare with incentive payments to alter these decisions. The approach is illustrated for the case of Best Management Practices (BMPs) mandated for nitrogen control in the Neuse River Basin in North Carolina. The empirical research shows that the economics of the BMPs are very different for the three regions in the basin as distinguished by physiographic conditions. Economic differences in implementing BMPs should be taken into account by state and federal authorities when they are determining cost-share programs. The research also shows that the cost-share payments offered for grass buffers might not be in line with the relative reduction in nitrogen emission offered by this BMP. [ABSTRACT FROM AUTHOR]