Use Of Best Management Practices Research Articles

Cover cropping to reduce nitrate loss through subsurface drainage in the northern U.S. corn belt.

Despite the use of best management practices for nitrogen (N) application rate and timing, significant losses of nitrate nitrogen (NO3(-)-N) in drainage discharge continue to occur from row crop cropping systems. Our objective was to determine whether a autumn-seeded winter rye (Secale cereale L.) cover crop following corn (Zea mays L.) would reduce NO3(-)-N losses through subsurface tile drainage in a corn-soybean [Glycine mar (L.) Merr.] cropping system in the northern Corn Belt (USA) in a moderately well-drained soil. Both phases of the corn-soybean rotation, with and without the winter rye cover crop following corn, were established in 1998 in a Normania clay loam (fine-loamy, mixed, mesic Aquic Haplustoll) soil at Lamberton, MN. Cover cropping did not affect subsequent soybean yield, but reduced drainage discharge, flow-weighted mean nitrate concentration (FWMNC), and NO3(-)-N loss relative to winter fallow, although the magnitude of the effect varied considerably with annual precipitation. Three-year average drainage discharge was lower with a winter rye cover crop than without (p = 0.06). Over three years, subsurface tile-drainage discharge was reduced 11% and NO3(-)-N loss was reduced 13% for a corn-soybean cropping system with a rye cover crop following corn than with no rye cover crop. We estimate that establishment of a winter rye cover crop after corn will be successful in one of four years in southwestern Minnesota. Cover cropping with rye has the potential to be an effective management tool for reducing NO3(-)-N loss from subsurface drainage discharge despite challenges to establishment and spring growth in the north-central USA.

Greening Development to Protect Watersheds: Does New Urbanism Make a Difference?

New urbanism has been touted as a more environmentally sustainable form of development than conventional low-density sprawl. To test this assertion, this study comparatively evaluates how well 50 matched pairs of new urban and conventional developments in the United States integrate watershed protection techniques. Findings indicate that new urban development practices offer a greener and more compact alternative to sprawl in greenfields on the suburban fringe, as they are more likely to protect and restore sensitive areas, reduce impervious cover, and incorporate best management practices. New urban developments in infill sites are more likely to incorporate impervious surface reduction techniques and restore degraded stream environments, but have equivalent levels of sensitive area protection and use of best management practices. Recommendations offer ways in which watershed protection techniques can be used to implement more environmentally sustainable development.

Forest Certification of State and University Lands in North Carolina: A Comparison

Abstract North Carolina State University, Duke University, and the North Carolina Division of Forest Resources (DFR) recently received both Forest Stewardship Council (FSC) and Sustainable Forestry Initiative (SFI) certification for their forests. Meeting SFI standards required better environmental management systems, improved use of best management practices, and better recordkeeping but few subsequent forest management changes. FSC required about the same environmental system changes but more forest management changes to favor future natural stand management and biodiversity protection. Costs included changes in forest management and recordkeeping to achieve forest certification, inspection expenses, prescribed changes in forest management, forgone timber revenues, and more stakeholder consultation. Benefits can include an improved professional reputation, better worker safety and training, better records and processes, more active public involvement, enhanced knowledge for outreach, better environmental management systems, more holistic management, and perhaps higher timber prices or greater market access.

WATER QUALITY MODELING OF ALTERNATIVE AGRICULTURAL SCENARIOS IN THE U.S. CORN BELT1

ABSTRACT: Simulated water quality resulting from three alternative future land‐use scenarios for two agricultural watersheds in central Iowa was compared to water quality under current and historic land use/land cover to explore both the potential water quality impact of perpetuating current trends and potential benefits of major changes in agricultural practices in the U.S. Corn Belt. The Soil Water Assessment Tool (SWAT) was applied to evaluate the effect of management practices on surface water discharge and annual loads of sediment and nitrate in these watersheds. The agricultural practices comprising Scenario 1, which assumes perpetuation of current trends (conversion to conservation tillage, increase in farm size and land in production, use of currently‐employed Best Management Practices (BMPs)) result in simulated increased export of nitrate and decreased export of sediment relative to the present. However, simulations indicate that the substantial changes in agricultural practices envisioned in Scenarios 2 and 3 (conversion to conservation tillage, strip intercropping, rotational grazing, conservation set‐asides and greatly extended use of best management practices (BMPs) such as riparian buffers, engineered wetlands, grassed waterways, filter strips and field borders) could potentially reduce current loadings of sediment by 37 to 67 percent and nutrients by 54 to 75 percent. Results from the study indicate that major improvements in water quality in these agricultural watersheds could be achieved if such environmentally‐targeted agricultural practices were employed. Traditional approaches to water quality improvement through application of traditional BMPs will result in little or no change in nutrient export and minor decreases in sediment export from Corn Belt watersheds.

Impacts of intensive harvesting on hydrology and nutrient dynamics of northern hardwood forests

Whole-tree clear-cutting and progressive strip-cutting of northern hardwood forests at the Hubbard Brook Experimental Forest in central New Hampshire resulted in measurable changes in physical and chemical conditions of forest streams. As a result of reduced transpiration and interception, water yield for the first year after whole-tree harvesting increased by >150 mm, the majority of which occurred during the growing season. Peak flows increased only moderately. Water yield and peak flow increases disappeared within 4-6 years as a result of rapidly regrowing vegetation. Sediment yields increased during and after harvesting but can be maintained within normal ranges of reference streams by careful use of best management practices. Stream chemistry changes occurred immediately following harvesting, most notably in the form of increases in concentrations of Ca2+, K+, NO3-, and H+. The concentrations return close to preharvest levels within 3-5 years. The above changes are discussed in terms of their causes and implications for aquatic habitat and fisheries.

Spatial and temporal variability of stream phosphorus in a New Zealand high‐country agricultural catchment

Spatial and temporal variability of stream total phosphorus (TP) concentrations and loadings was evaluated over a year in a high‐country agricultural catchment. One storm event was also sampled at the inflow to a lake. An upland tributary had the highest median concentration (0.064 mg 1‐1), but the maximum (0.614 mg 1‐1) occurred at the inflow during the storm. Values near the lake surface were low but increased with depth in summer. There was a large difference between two streams, and values exceeded water quality guidelines in several locations. Seasonality in concentrations was not evident. Mean and median loadings at the inflow were approximately 7000 and 680 g day‐1, respectively, and the maximum was 81 540 g day‐1during the storm. TP loadings to the lake during a synoptic survey were 470 g day‐1 or 13 g km‐2day‐1. The lower half of the catchment contributed 72% of the loading to the lake. Baseflow, snowmelt, and one storm accounted for 47%, 30%, and 23%, respectively, of the total annual loading. Fertiliser, livestock waste, and trampling of stream banks by livestock contribute to the problem and can be minimised though use of best management practices in areas identified in this study.

Impacts of intensive harvesting on hydrology and nutrient dynamics of northern hardwood forests

Whole-tree clear-cutting and progressive strip-cutting of northern hardwood forests at the Hubbard Brook Experimental Forest in central New Hampshire resulted in measurable changes in physical and chemical conditions of forest streams. As a result of reduced transpiration and interception, water yield for the first year after whole-tree harvesting increased by >150 mm, the majority of which occurred during the growing season. Peak flows increased only moderately. Water yield and peak flow increases disappeared within 4-6 years as a result of rapidly regrowing vegetation. Sediment yields increased during and after harvesting but can be maintained within normal ranges of reference streams by careful use of best management practices. Stream chemistry changes occurred immediately following harvesting, most notably in the form of increases in concentrations of Ca2+, K+, NO3-, and H+. The concentrations return close to preharvest levels within 3-5 years. The above changes are discussed in terms of their causes and implications for aquatic habitat and fisheries.

The adoption of best management practices to reduce agricultural water contamination

Nonpoint source water pollution generated by agricultural production is considered a major environmental issue in the United States and Europe. One strategy in the United States has been to adopt various measures, called best management practices (BMPs), to reduce water pollution. Our research addresses legal institutions and the applied use of BMPs, and discusses compensatory payments to reduce nitrogen fertilization levels. Models employed in Georgia and Baden-Wuerttemberg evaluate institutional constraints of payments to reduce nitrogen usage, penalties for excessive leaching, and financial incentives for meeting minimum mineralized nitrogen levels. By modeling net returns, preferred economic strategies for producers are identified. Results show that while BMPs can reduce agricultural nonpoint contamination, pollution abatement may be costly to producers. Thus, reduced pollution probably will require some type of government intervention.

Best management practices applied to urban runoff quantity and quality control

South Africa currently has one of the highest rates of urbanisation in the world causing a significant increase in surface water runoff. This, in turn, causes increased flooding and a significant decrease in water quality due primarily to the accumulation of pollutants. The need exists to manage urban stormwater runoff on an integrated catchment basis, thereby reducing the negative impact of urbanisation on the environment and quality of life. In this paper, details on how existing problem areas can be identified and ranked, the use of Best Management Practices (BMPs) to reduce the impacts of urbanisation on the environment and the effectiveness of BMP's are discussed and illustrated, based on expertise gained from studies in South Africa as well as visits to the USA and Australia.

Best management practices applied to urban runoff quantity and quality control

South Africa currently has one of the highest rates of urbanisation in the world causing a significant increase in surface water runoff. This, in turn, causes increased flooding and a significant decrease in water quality due primarily to the accumulation of pollutants.The need exists to manage urban stormwater runoff on an integrated catchment basis, thereby reducing the negative impact of urbanisation on the environment and quality of life.In this paper, details on how existing problem areas can be identified and ranked, the use of Best Management Practices (BMPs) to reduce the impacts of urbanisation on the environment and the effectiveness of BMP's are discussed and illustrated, based on expertise gained from studies in South Africa as well as visits to the USA and Australia.

EFFECTS OF BEST MANAGEMENT PRACTICES ON FOREST STREAMWATER QUALITY IN EASTERN KENTUCKY1

ABSTRACT: Forest land managers are concerned about the effects of logging on soil erosion, streamflow, and water quality and are promoting the use of Best Management Practices (BMPs) to control impacts. To compare the effects of BMP implementation on streamwater quality, two of three small watersheds in Kentucky were harvested in 1983 and 1984, one with BMPs, the other without BMPs. There was no effect of clearcutting on stream temperatures. Streamflow increased by 17.8 cm (123 percent) on the BMP watershed during the first 17 months after cutting and by 20.6 cm (138 percent) on the Non‐BMP watershed. Water yields remained significantly elevated compared to the uncut watershed 8 years after harvesting. Suspended sediment flux was 14 and 30 times higher on the BMP and Non‐BMP Watersheds, respectively, than on the uncut watershed during treatment, and 4 and 6.5 times higher in the 17 months after treatment was complete. Clearcutting resulted in increased concentrations of nitrate, and other nutrients compared to the uncut watershed, and concentrations were highest on the non‐BMP watershed. Recovery of biotic control over nutrient losses occurred within three years of clearcutting. The streamside buffer strip was effective in reducing the impact of clearcutting on water yield and sediment flux.

Aspects of Functional Analysis of Mitigated Wetlands Receiving Highway Runoff

The wetland mitigation and storm water management provisions in the 1987 Clean Water Act significantly affect transportation agencies. A common requirement of these federal storm water management provisions and state storm water regulations is the use of best-management practices (BMPs). The Virginia Department of Transportation has constructed more than 200 wetlands and many storm water BMPs, such as detention basins. A potentially cost-effective approach to satisfying wetland mitigation requirements and storm water regulations is to use mitigated wetlands as storm water BMPs. A multifunctional evaluation of two mitigated wetlands receiving highway runoff is presented to examine the feasibility of using mitigated wetlands as storm water BMPs. Influent and effluent water quality and quantity were monitored at the sites during storm events. Vegetation density and diversity and wetland wildlife were examined as functional indicators because they were believed to be the most likely to be impaired by highway runoff. Data collected were stored in a geographic information system, which was developed to serve as a database for current and future monitoring of mitigated wetland sites. Both sites had peak reductions in excess of 40 percent, with attenuation of greater than 90 percent for a system combining a detention basin and a mitigated wetland in series. Removal rates were as high as 90 percent for total suspended solids, 65 percent for chemical oxygen demand, 70 percent for total phosphorus and orthophosphate, and 50 percent for zinc. Despite having highway runoff as a primary water source, both sites support apparently healthy and diverse vegetative communities and provide habitat for a variety of wildlife.

Bromide and Nitrogen‐15 Tracers of Nitrate Leaching under Irrigated Corn in Central Nebraska

AbstractNitrate leaching from agricultural fields into groundwater has caused environmental and health concerns. A study was conducted during 1992–1993 in the Central Platte Valley of Nebraska to assess the nitrate leaching potential under recommended center‐pivot irrigation and fertilizer best management practices for continuous corn (Zea mays L.). At time of planting corn, potassium bromide (KBr) and double‐labeled 15N ammonium nitrate (10 atom% 15NH415NO3) tracers were applied at rates of 200 kg Br ha−1 and 30 kg N ha−1 to four 6.1 by 3.7 m plots that were representative of major soil types on the 32.1‐ha field. Soil and plants sampled 7 wk after planting and at harvest in 1992, and in the spring of 1993, were analyzed for Br and N content and a mass balance was determined. At corn harvest, 41% (81.9 kg ha−1) of the applied Br loss from the top 1.2 m of soil was attributed to leaching. Also, 54% (16.2 kg ha−1) of the tracer applied was lost from the system; 41% (12.3 kg ha−1) through leaching; and 13% (3.9 kg ha−1) through denitrification and volatilization. By time of planting in the spring of 1993, 70% (139.3 kg ha−1) of the applied Br and 46% (13.8 kg ha−1) of the fertilizer N leached below 1.2 m. High negative correlations were found between soil clay and silt contents, and Br or NO3 leaching. Despite use of best management practices for irrigation water and N applications, large amounts of nitrate can be lost through leaching under irrigated corn in this subhumid climate on fine‐ to medium‐textured soils.

Strategies for protecting Florida's everglades: the best management practice approach

The Everglades Agricultural Area (EAA) is a small portion of the Everglades region, consisting of an artificially drained area of approximately 280 000 ha of organic soils providing a rich environment for the cultivation of primarily sugar cane, vegetables, rice, and sod. Hydroperiods and excessive nutrients in surface water inflows have been identified as potentially disruptive to the natural ecosystem, with phosphorus (P) deemed to be the limiting nutrient. Hence, agricultural drainage water from the EAA, containing higher than background P loads and concentrations, has been targeted as a source of the problem. To reduce P loads and concentrations in the drainage water leaving farms in the EAA, on-farm best management practices (BMPs) can be used. These BMPs have been identified and tested at the large plot scale and are presently being implemented and their efficacy verified at the farm level. It is currently estimated that P loading from the EAA can be reduced by 20% to 60% using BMPs. A 45% reduction should be attainable while keeping within acceptable cost/benefit ratios. The use of BMPs, however, will require higher levels of farm management and more sophisticated tools for decision-making.

Strategies for protecting Florida's everglades: The best management practice approach

The Everglades Agricultural Area (EAA) is a small portion of the Everglades region, consisting of an artificially drained area of approximately 280 000 ha of organic soils providing a rich environment for the cultivation of primarily sugar cane, vegetables, rice, and sod. Hydroperiods and excessive nutrients in surface water inflows have been identified as potentially disruptive to the natural ecosystem, with phosphorus (P) deemed to be the limiting nutrient. Hence, agricultural drainage water from the EAA, containing higher than background P loads and concentrations, has been targeted as a source of the problem. To reduce P loads and concentrations in the drainage water leaving farms in the EAA, on-farm best management practices (BMPs) can be used. These BMPs have been identified and tested at the large plot scale and are presently being implemented and their efficacy verified at the farm level. It is currently estimated that P loading from the EAA can be reduced by 20% to 60% using BMPs. A 45% reduction should be attainable while keeping within acceptable cost/benefit ratios. The use of BMPs, however, will require higher levels of farm management and more sophisticated tools for decision-making.

FOREST PRACTICES AS NONPOINT SOURCES OF POLLUTION IN NORTH AMERICA1

ABSTRACT: Forest management activities may substantially alter the quality of water draining forests, and are regulated as nonpoint sources of pollution. Important impacts have been documented, in some cases, for undesirable changes in stream temperature and concentrations of dissolved oxygen, nitrate‐N, and suspended sediments. We present a comprehensive summary of North American studies that have examined the impacts of forest practices on each of these parameters of water quality. In most cases, retention of forested buffer strips along streams prevents unacceptable increases in stream temperatures. Current practices do not typically involve addition of large quantities of fine organic material to streams, and depletion of streamwater oxygen is not a problem; however, sedimentation of gravel streambeds may reduce oxygen diffusion into spawning beds in some cases. Concentrations of nitrate‐N typically increase substantially after forest harvesting and fertilization, but only a few cases have resulted in concentrations approaching the drinking‐water standard of 10 mg of nitrate‐NIL. Road construction and harvesting increase suspended sediment concentrations in streamwater, with highly variable results among regions in North America. The use of best management practices usually prevents unacceptable increases in sediment concentrations, but exceptionally large responses (especially in relation to intense storms) are not unusual.

LAWS AND PROGRAMS FOR CONTROLLING NONPOINT SOURCE POLLUTION IN FOREST AREAS1

ABSTRACT: Recent federal legislation strengthened nonpoint source pollution regulations and helped to support and standardize pollution control efforts. A comprehensive review of current state and federal programs for forest areas reveals a substantial increase in agency water quality protection activities. These new efforts emphasize monitoring to assess the use and effectiveness of best management practices (BMPs). Recent monitoring reveals that BMP use is increasing and that such use typically maintains water quality within standards. However, information is generally lacking about the cost effectiveness of BMP programs. Carefully designed and executed monitoring is the key to better specification of BMPs and more cost effective water quality protection. (KEY TERMS: water quality; nonpoint source pollution; water law; watershed management; forestry; best management practices.)

REGULATING NONPOINT SOURCE POLLUTION IN SURFACE WATERS: A PROPOSAL1

ABSTRACT: Nonpoint sources (NPS) are an important and continuing source of toxic and conventional pollutants to surface waters. The Clean Water Act amendments of 1987 call for the regulation of these sources through the use of Best Management Practices (BMP). However, BMP implementation has generally occurred on a voluntary basis. This paper proposes a regulatory mechanism to control nonpoint source pollution. The regulatory mechanism involves the development of consortia, made up of all parties potentially responsible for NPS pollution, the development of wasteload allocations that coordinate the pollutant contributions from both point and nonpoint sources in a stream segment, and the issuance of permits to consortia to regulate the impacts of NPS pollution and ensure achievement of state or federal Water Quality Criteria and Standards.

Demonstrating Agricultural Best Management Practice Implementation and Impacts on a Commercial Farm

Degraded water quality in the Chesapeake Bay and its tributaries has been attributed in part to agricultural contributions of nonpoint source (NPS) pollutants, particularly nutrients. To encourage the adoption of agricultural best management practices (BMPs) and the control of nutrients from agricultural land use, the State of Maryland funded development of a demonstration farm. The farm is becoming a valuable means by which to showcase BMPs to both agricultural and non-agricultural audiences, and by which to obtain economic and water quality data concerning the use of BMPs on a commercial farm. Unusual weather patterns during the study make conclusions to date tentative and highlight considerations that should be made before using commercial farms as demonstration sites. Experience in developing this continuing demonstration shows that significant funding is required, that firm implementation schedules cannot be expected, and consequently, that depending on objectives several years are required to develop a successful onfarm BMP effectiveness demonstration.

Nitrate contamination of groundwater in North America

Groundwater serves as the primary domestic water supply for over 90% of the rural population and 50% of the total population of North America. Consequently, protection of groundwater from contamination is of major concern. This paper reviews the problem of controlling nitrate pollution of groundwater in North America. Nitrates in groundwater originate from a number of non-point sources, including geological origins, septic tanks, improper use of animal manures, cultivation (especially fallowing) precipitation, and fertilizers. Accumulation of nitrate N in groundwater is probably attributed to different sources for different regions. Major areas of nitrate pollution often occur under irrigation because leaching is required to control salt accumulation in the root zone. In the last few decades, areas under irrigation and the use of N fertilizers have increased greatly, and both of these have probably contributed to groundwater nitrate problems. Use of known best management practices (irrigation scheduling; fertilization based on calibrated soil tests; conservation tillage; acceptable cropping practices; recommended manuring rates) has been demonstrated to be highly effective in controlling leaching of nitrates. Government policies are needed that will encourage and reward the use of the best management practices that help control nitrate accumulations in groundwater.