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While basin-scale studies and modeling are important tools in relating land uses to water quality concerns, edge-of-field monitoring (EOFM) provides the necessary resolution to spatially target, design, and evaluate in-field conservation practices for reducing nonpoint source pollution from agriculture. This paper introduces this special issue of the Journal of Soil and Water Conservation, a collection that provides an overview of EOFM on agricultural lands. The issue describes the transition of EOFM from a mainly research endeavor to on-farm monitoring of the environmental impact and performance of agricultural practices and addresses topics such as (1) disconnect between large-scale loading estimates and the prevalence of sound nutrient management practices; (2) obstacles in identifying the causes, sources, and solutions to agricultural nonpoint source pollution; (3) progress evaluation at the watershed scale; (4) need for additional multiscale studies to better understand the fate and transport continuum and establish linkages between EOFM and in-stream water quality; (5) history of EOFM and recent advances; and (6) alternative methods to determine whether EOF results are acceptable. The increased attention on agricultural runoff has concurrently raised awareness of the need for EOFM. It is at the field scale that data are needed to better understand the fate of sediment and applied nutrients and inform adaptive management to mitigate offsite losses. This special issue compiles the latest scientific information related to utilizing EOFM to evaluate and address agricultural nonpoint sources, and provides a glimpse of EOFM in the future. [ABSTRACT FROM AUTHOR]

Previous research predicted that the biofuel-driven expansion of corn (Zea mays L.) area would increase riverine export of nitrate-nitrogen (NO3-N) in the Mississippi River Basin. Accurate information about water quality trends in agricultural watersheds is needed to better inform agricultural policy and to help quantify the effectiveness of field and landscape management practices. This study was designed to (1) characterize possible NO3-N trends within the Raccoon River watershed (RRWS) of central Iowa, and (2) explore links between the relative areas planted to corn and soybean (Glycine max) and water quality. We examined NO3-N concentration and loading data from more than 60 main stem river and tributary locations in the RRWS for the period 1999 to 2014. In addition, we assessed the role of climate, crop rotations, and simplified annual N budgets on NO3-N concentrations and loads to show that expansion of corn area has not increased Raccoon River NO3-N levels. Nitrate-N concentrations have not increased as corn area increased 19% and fertilizer N inputs increased 24% since 1999. We conclude that expansion of corn area at the expense of soybean may be affecting water quality. Better management of soybean in a corn-soybean rotation should reduce NO3-N export from the watershed, and reducing throughput of water in this artificially drained system will improve water quality. [ABSTRACT FROM AUTHOR]

The article offers information on the history, purpose and significance of the U.S. federal soil and water conservation programs such as the Conservation Reserve Program (CRP). It informs that these programs deliver effective changes to values of agricultural landscapes thereby providing an opportunity to conserve soil, water and wildlife on private lands. It discusses the significance of the Natural Resources Conservation Service (NRCS) in supporting agriculture.

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.

Accurate and quick field estimation of crop residues is important for carbon sequestration and biofuel production programs. Landscape-scale assessment of this vital information has resorted to the use of remote sensing technology. The cellulose absorption index (CAI) technique has outperformed other indices for discriminating bare soil and crop residue in the Midwest, but has not been tested in the Pacific Northwest and the Central and Northern Great Plains regions of the United States. The objective of this study is to assess the performance of CAI in these regions. Malting barley (Hordeum vulgare L.), spring wheat (Triticum aestivum L.), durum (Triticum turgidum L.), field pea (Pisum sativum L.), and fallow following spring wheat and proso millet (Panicum miliaceum L.) were used in the assessment. Using a portable ground-based spectroradiometer, as well as transect line and photo-grid methods, crop residue cover was measured after the 2009 harvest season. Samples were collected for laboratory analyses. Linear regression analysis showed CAI explained 41% to 55% of the variation in the residue cover. Field pea and fallow residue cover had better correlation with CAI than did small grain crop residues. Field and laboratory measurement of CAI showed that varying pea residue cover responded significantly different than other crop residues. The performance of CAI was affected by the type of crop rather than by location and soil type in the regions. Among other measured parameters, percentage crop residue cover, hemicellulose, and residue amount were most correlated with CAI. Results document that CAI can quickly and effectively estimate percentage of residue cover in the regions. [ABSTRACT FROM AUTHOR]

The article focuses on enhancing multifunctionality to offer ecosystem services for the agicultural landscape in the U.S. It says that the methods from the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) are used to accomplish the enhancement of ecosystem services. It notes that landscape ecological planning and design that maximizes the provision of cost-effectiveness and ecosystem services are difficult to conduct due to problems such as manpower skills.

The USDA Farm Bill conservation programs provide landowner incentives to remove less productive and environmentally sensitive lands from agricultural production and reestablish them in natural vegetation (e.g., native grasses, trees, etc.) to achieve conservation objectives. However, removal of arable land from production imposes an opportunity cost associated with loss in revenue from commodities that otherwise would have been produced. Recent Farm Bills have increasingly emphasized targeted practices to achieve specific environmental outcomes that maximize environmental benefits relative to cost. The Habitat Buffers for Upland Birds practice (CP-33) under the continuous Conservation Reserve Program is an example of a targeted conservation practice that has produced measureable outcomes (increased bobwhite and grassland bird populations) with relatively minor changes in primary land use. However, establishing conservation buffers on profitable farmland may be incompatible with the economic objectives of landowners/producers. Precision agriculture technologies provide a powerful conservation planning tool for identifying environmental and economic opportunities in agricultural systems. Precision implementation of conservation practices, such as CP-33, is the foundation of strategic conservation planning and is essential for optimization of environmental and economic benefits. Toward this end, we developed a geospatial decision support tool (Arc GIS tool) to inform this decision-making process. We illustrate the geoprocessing workflow of the tool and demonstrate the conditions under which precision implementation of conservation practices can concomitantly increase whole-field profitability and environmental services for an example farm in Mississippi. [ABSTRACT FROM AUTHOR]

Nonuniform field runoff can reduce the effectiveness of filter strips that are a uniform size along a field margin. Effectiveness can be improved by placing more filter strip where the runoff load is greater and less where the load is smaller. A modeling analysis was conducted of the relationship between pollutant trapping efficiency and the ratio of filter strip area to upslope contributing area, i.e., buffer area ratio. The results were used to produce an aid for designing filter strips having consistent effectiveness along field margins where runoff load is nonuniform. Simulations using the process-based Vegetative Filter Strip Model show that sediment and water trapping efficiencies of a filter strip increase nonlinearly as the buffer area ratio gets larger. Site characteristics, including slope, soil texture, and upslope soil cover management practices, help to define this relationship more accurately. Using the Vegetative Filter Strip Model simulation results, a graphical design aid was developed for estimating the buffer area ratio required to achieve specific trapping efficiencies for different pollutants under a broad range of agricultural site conditions. A single graph was produced showing simulation results for seven scenarios as a family of lines that divide the full range of possible relationships between trapping efficiency and buffer area ratio and into fairly even increments. Simple rules guide the selection of one line that best describes a given field situation by considering slope, soil texture, and field cover management practices. Relationships for sediment-bound and dissolved pollutants are interpreted from the Vegetative Filter Strip Model results for sediment and water. The design aid is easy to use, accounts for several major variables that determine filter strip performance, and is based on a validated, process-based, mathematical model. The use of this design aid will enable a more precise fit between filter size and runoff load where runoff from agricultural fields is nonuniform. [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 discusses the impacts of the 2008 spring rains and flooding on the agricultural fields in Illinois, Missouri and Indiana. It notes that the flooding and erosion events that occurred in the three regions have resulted to delayed corn and soybean planting, crop loss, and damaged levees and agricultural lands. It recommends that separating watersheds with high-slope gradients and well-drained soils is important to reduce the effects of floods.

The article focuses on the use of agricultural lands and soil carbon in the U.S. It mentions that land management and productivity were restored after the Dust Bowl and the World War II including the use of agricultural chemical, the improvement in crop varieties and the greater mechanization. It also underscores the development of several land conservation programs such as the Soil Bank Program in 1956. The role of soil organic carbon in the country's agricultural land is also explored.

Nonpoint P sources from the agricultural landscape are a significant environmental problem for surface water bodies because of the promotion of eutrophication. Many states have developed P assessment tools to help differentiate land uses and their potential for P losses to surface water. Kansas has developed such a P index (PI), and the purposes of this paper are to report on the calibration of that index against data collected from four runoff studies and to explore the modification of the PI as a means to improve the predictive capability of the PI. The PI includes soil test P, rate and application method for P from fertilizers and manure, soil erosion, runoff class, distance from surface water bodies, and irrigation erosion as inputs. As originally proposed, the PI was well correlated with soluble P (r = 0.93) and bioavailable P (r = 0.94) losses but was less correlated with total P (r = 0.79). By modification of the PI, the r values improved to 0.97 for bioavailable P, 0.95 for soluble P, and 0.89 for total P. Of the 90 plots at four different sites, plots from Neosho and Franklin-1 and Franklin-2 sites were ranked as having very low and low vulnerability to P loss (82%) whereas plots in the Riley County site were ranked as high and very high vulnerability to P loss (18%) due to manure applications. Therefore, for only the Riley site, P management strategies need to be modified to reduce P losses. Moreover, additional P applications are not warranted for this site. Using soil test P as a single factor to predict P losses in runoff for our sites produced results similar to using the modified PI. [ABSTRACT FROM AUTHOR]

The article reports on the science-based plan vision of the Conservation Effects Assessment Project (CEAP) initiated by the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NCRS). CEAP's science-based plan is designed to help meet the conservation and technology challenges of the future through multi-agency assessment, research, and outreach-extension program. It aims to enhance natural resources and ecosystems through effective conservation and better management of agricultural landscapes. It is also designed to examine the management of agricultural landscapes for environmental quality.

Agricultural drainage ditches are essential for the removal of surface and ground water to allow for crop production in poorly drained agricultural landscapes. Ditches also mediate the flow of pollutants from agroecosystems to downstream water bodies. This paper provides an overview of the science, management, and policy of ditches. Ditches provide a unique opportunity to address nonpoint source pollution problems from agriculture due to the concentration of the contaminants and the engineered nature of ditch systems. A better understanding of the nature of these complex system and the technologies available and under development to improve their management will assist in the design and implementation of water quality protection programs. [ABSTRACT FROM AUTHOR]

Soil erosion is one of the biggest contributors to nonpoint source pollution in the United States. Soil loss rates from construction sites are 10 to 20 times that of agricultural lands. The use of surface applied organic amendments has been shown to reduce runoff and erosion through enhanced vegetation growth and soil quality characteristics. The objective of this study was to evaluate the vegetation growth and soil quality effects from compost blanket and hydroseed applications to soils disturbed by construction activities. Four types of compost blankets, two hydroseeded treatments (silt fence and mulch filter berm) and a bare soil (control) were applied in field test plots. Treatments were seeded with common Bermuda grass (Cynodon doctylon). Vegetative growth (percent cover and biomass of weeds and grasses) and soil quality characteristics were evaluated periodically over one year and 18 months, respectively. Results showed compost blankets provided an average of 2.75 times more vegetative cover than hydroseed after three months. After one year, cover was similar, but hydroseed had significantly greater weed biomass than compost and a greater ratio of weed biomass relative to Bermuda grass biomass. One type of compost blanket increased surface soil extractable organic carbon, and another type increased organic matter in o to 15 cm (0 to 6 in) soil depths relative to hydroseed treated soils. A one-time application of hydroseed that included mineral phosphorus (P) fertilizer elevated surface soil P after 18 months. On construction sites where disturbed soils are prone to erosion and vegetation establishment is required, compost applications will promote quicker vegetation cover with less weed growth than hydroseeding. Some compost erosion control blankets have the ability to increase soil quality characteristics relative to hydroseed applications within 18 months of application. [ABSTRACT FROM AUTHOR]

Tolerable soil toss (T) is defined as the maximum rate of annual soil erosion that economically and indefinitely will continue to sustain a high level of crop productivity. Currently a T value is assigned to a soil based on its current functional state and structural integrity. However, in India a default T value of 11.2 Mg ha-1 yr-1 (5.0 t ac-1 yr-1) is being followed. Our objective is to provide adjusted T values for India's Northwest Himalayan region by incorporating bulk density, water stable aggregate measurements, infiltration rate, soil carbon, and fertility status into the assessment. A quantitative model was used to sum up overall soil performance to define the current state of soil resource. Scaling functions were used to convert soil parameters to a 0 to 1 scale. The normalized values were then multiplied by appropriate weighting factors based on relative importance and sensitivity analysis of each indicator. A categorical ranking of soil 1, 2, or 3 was given to a soil group based on the overall assessment. A general guideline developed by the USDA-Natural Resources Conservation Service (NRCS) was followed to calculate soil loss tolerance for each soil group using effective soil depth. Adjusted T values for the area ranged between 5.0 and 12.5 Mg ha-1 yr-1 (2.2 and 5.6 t ac-1 yr1) compared to 11.2 Mg ha-1 yr-1 (5.0 t ac-1 yr1). Use of the adjusted T values will improve conservation planning, help meet erosion control regulations for development of sustainable farm operations, and improve watershed management in this portion of India. [ABSTRACT FROM AUTHOR]

There is increasing recognition that spatial variability in soils occurs across the landscape within a field and that differential management practices are warranted. Differences in herbicide persistence in the soil can result in variation in crop injury across the landscape. Soil pH, which is also reported to vary across the landscape, influences herbicide persistence. Thus, this study investigates the ability to map and delineate within-field soil pH variability using landscape segmentation analysis and provide a tool for predicting herbicide persistence. The area, comprising a conventional and a no-till field in southern Alberta, was surveyed using a dual frequency global positioning system; a digital elevation model was created and landform segments defined. Four landform segments were effective in delineating soil pH zones that could be related to herbicide persistence. The lower slopes in both fields, with pH < 6.0, showed imidazilinone persistence. Carryover of sulfonylurea and triazine herbicides was evident in the upper slopes of the conventional till field only (pH 7.8(7.9). The results suggest that landscape segmentation modeling could provide a valuable tool in managing field spatial variation in soil. [ABSTRACT FROM AUTHOR]

Analyses of farmland conversion typically rely on data that has been aggregated to a county level. However, the pattern of farmland conversion at the individual parcel level could have important implications for the sustainability of agricultural operations within a limited geographic area. This paper uses data on farm parcels that have withdrawn from Tennessee's differential assessment program to track farmland conversion at the individual tax parcel level for a single east Tennessee county. The pattern and pace of farmland conversion is described over an 18-year period and a metric from the habitat fragmentation literature-edge density-is used to quantify the extent to which this conversion has increased the fragmentation of the county's remaining agricultural lands. Edge density, as used in this paper, provides a relative measure of the extent of the interface between agriculture and other land uses. The results suggest that agricultural lands became more fragmented every year for which data was available, although the extent of this increase varied substantially from one year to the next. More specifically, while conversion to residential use increased fragmentation, conversion to both commercial and industrial uses tended to decrease fragmentation. The data and methodologies employed in this paper, although relatively new to the farmland conversion literature, could prove to be valuable tools in analyzing the conversion of agricultural lands and in designing policies to ameliorate the adverse effects of such conversion. [ABSTRACT FROM AUTHOR]

The major water quality impairment in the Midwest United States is sediment eroded from agricultural lands. Yet, few understand where or when erosion occurs, or the dynamics of soil erosion, the relative impact of precipitation, topography, land management and severe events over time and space. The objectives of this project are to: 1) develop methodology for estimating near real time spatial and temporal soil erosion and water runoff losses; and 2) explore issues in applying the method to a large area by setting up and running a prototype system for the state of Iowa. To accomplish this, soil erosion and water runoff loss are estimated daily at the township level (-10 by -10 km area) (-6.2 mi)2 and a map is posted on the Internet daily showing precipitation with runoff and soil erosion estimates for every Iowa township. We use Water Erosion Prediction Project (WEPP), a daily simulation model, to compute soil erosion and surface runoff. WEPP uses accumulated precipitation by 15-minute periods obtained with NEXRAD `radar. Other needed weather data are obtained from an Iowa weather network. The National Resources Inventory provides soil, topography, cropping and management information required for running WEPP. Daily and annual spatial precipitation, runoff and erosion estimates illustrate a high level of spatial variability related to topography, precipitation characteristics, soils and management practices. [ABSTRACT FROM AUTHOR]

The article reports on what science can and cannot supply to policy makers in managing agricultural landscapes for environmental quality. Science can provide policy makers such as those with great influence on conservation policy with useful tool for the design, implementation, and management of conservation programs. It can give useful input to policy makers through government programs which can be standard operating procedure for many agencies. It can also be helpful through guiding policy makers in making initial decision by understanding the importance and impact of conservation policies and adaptive management of the program. On the other hand, science cannot offer policy makers discrete choices with discrete results regarding conservation projects.

The article provides information on a multidisciplinary workshop which will be held on October 11 to 13, 2006 at the Westin Crown Center Hotel in Kansas City, Missouri. The initiative is designed for individuals who focuses on the environmental benefits of agricultural land conservation at landscape or watershed scales. Key information regarding the registration for the conference are also given.

Conservation buffers, such as filter strips and riparian forest buffers, are widely prescribed to improve and protect water quality in agricultural landscapes. These buffers intercept field runoff and retain some of its pollutant load before it reaches a waterway. A buffer typically is designed to have uniform width along a field margin and to intercept runoff that flows uniformly to it. However, spatial analysis of field conditions and runoff patterns indicate that more runoff is likely to flow to some locations along a field margin than to others which can substantially limit a buffer's effectiveness. We propose that precision conservation, the use of precision spatial information, technologies, and procedures to implement conservation practices, can be used to improve the design of buffers and ensure their effectiveness. Precision conservation can integrate detailed landscape data with mathematical models in a geographic information system. We can then analyze spatial patterns of runoff and design variable-width buffers that precisely match the needs of every location along a waterway. Greater cost of precision conservation is offset partly by greater water-quality benefit from each acre of buffer. Many of the required data sources and modeling components already exist, substantial improvements are possible that can produce even greater conservation efficiency. [ABSTRACT FROM AUTHOR]

Effective watershed-scale planning integrates place-based social information with physical landscape data to create solutions appropriate for local communities. Implicit in this integration is an understanding of the differences between planners and residents. This research utilized a multi-disciplinary social assessment to obtain information about these differences and how they might impact planning and decision-making for a polluted water supply reservoir. The assessment was structured to compare assumptions in technical understanding and social dynamics among the planning team, watershed residents, and local public officials. Results were integrated into planning efforts affecting how potential landscape changes to enhance water quality were approached, communication strategies between planners and residents, and the structure of project planning and decision-making. Given the large numbers of planning projects that require effective public participation for decision-making and implementation to meet objectives, this type of information and methodologies to collect and integrate it early in a project will be essential. [ABSTRACT FROM AUTHOR]

The threat of global climate change has provoked policy-makers to consider plausible strategies to slow the accumulation of greenhouse gases--especially carbon dioxide (CO2)--in the atmosphere. One such idea involves the sequestration of atmospheric carbon (C) in degraded agricultural soils as part of the Conservation Reserve Program (CRP). While the potential for significant C sequestration in CRP grassland ecosystems has been demonstrated, the paired-site sampling approach traditionally used to quantify soil C changes has not been evaluated with robust statistical analysis. In this study, 14 paired CRP (> 8 years old) and cropland sites in Dane County, Wisconsin, were used to assess whether a paired-site sampling design could detect statistically significant differences (ANOVA) in mean soil organic C and total nitrogen (N) storage. We compared 0 to 10 cm (0 to 3.9 in) bulk density and sampled soils (0 to 5 cm, 5 to 10 cm, and 10 to 25 cm [0 to 2 in, 2 to 3.9 in, and 3.9 to 9.8 in]) for textural differences and chemical analysis of organic matter (OM), soil organic C (SOC), total N, and pH. The CRP contributed to reducing soil bulk density by 13% (p < 0.0001) and increased SOC and OM storage (kg m-2 [lb ft-2]) by 13% to 17% in the 0 to 5 cm (2 in) layer (p = 0.1). We tested the statistical power associated with ANOVA for measured soil properties and calculated minimum detectable differences (MDD). We concluded that 40 to 65 paired sites and soil sampling in 5 cm (2 in) increments near the surface were needed to achieve an 80% confidence level (a = 0.05; b = 0.20) in soil C and N sequestration rates. Because soil C and total N storage was highly variable among these sites (CVs > 20%), only a 23% to 29% change in existing total organic C and N pools could be reliably detected. While C and N sequestration (247 kg C ha-1 yr-1 and 17 kg N ha-1 yr-1 [220 lb C ac-1 and 15 lb N ac-1]) may be occurring and confined to the surface 5 cm (2 in) as part of the Wisconsin CRP, our sampling design did not statistically support the desired 80% confidence level. We conclude that usage of statistical power analysis is essential to insure a high level of confidence in soil C and N sequestration rates that are quantified using paired plots. [ABSTRACT FROM AUTHOR]