The Natural Resources Conservation Service (formerly The Soil Conservation Service) is part of the United States Department of Agriculture. NRCS has an extensive network of 2,493 field offices, covering all states and territories. We are closely allied with 3,000 local conservation districts that act as steering committees to foster locally led conservation efforts.Historically our goal has been to reduce soil erosion on private land. We have only seriously been in the water quality arena for the past 10 years. This concern with water quality is the primary reason we became interested in pest management and pesticide use. Today, NRCS's goal is centered on conserving all natural resources.
In order to support comprehensive conservation planning, NRCS employs an impact evaluation process we refer to as SWAPA+H which stands for: Soil, Water, Air, Plants, Animals plus Human considerations. SWAPA+H planning requires examination of the potential positive and negative impacts of existing and potential management alternatives. Risks and benefits must be quantified for each practice being applied, be it erosion control, irrigation water management, pest management or nutrient management. Practices are then balanced to create a "Resource Management System" which minimizes harmful impacts to all resources while maximizing positive impacts, including economic benefits to farmers.
All participation in NRCS programs is voluntary. We have incentive programs that can assist farmers and landowners with monetary and technical support for adopting conservation practices. Pest and pesticide management is covered for the most part by one cost share/incentive program. Funded through the 1996 Farm Bill, EQIP (Environmental Quality Incentive Program) provides technical, financial and educational assistance in designated priority areas.
NRCS administers EQIP and the USDA Farm Services Agency is responsible for making EQIP cost share and incentive payments to farmers. Integrated Pest Management (IPM) is eligible for EQIP incentive payments and is applied under the NRCS Pest Management Conservation Practice Standard (Standard #595). EQIP IPM incentive payments are for IPM practices that reduce the environmental risk associated with pest management.
Approximately 6.6 million dollars went to this EQIP function nationally in FY 1997. EQIP incentive payments are made on a per acre basis and are set by NRCS State Conservationists with the help of EQIP State Technical Committees. Typically, payments range from 5 to 15 dollars per acre. The amount of theses payments is usually based on the cost of pest scouting for a particular crop. In 1997, approximately 1 million acres of IPM cropland was covered by EQIP. EQIP is targeted to high priority areas nationally. NRCS State Conservationists designate priority areas within states, based on advice from State Technical Committees. This means that some producers may not be eligible to sign up for EQIP some years. However, once an EQIP contract is made, it can include up to three years of IPM incentive payments. It may be possible to later make EQIP IPM incentive payments for an additional 3 years for a new IPM practice which substantially improves environmental quality over the previous contract's goals.
Technical support for NRCS field offices is being provided nationally by revamping our Nutrient and Pest Management Policy and updating our Conservation Practice Standards. The timing of these activities coincides with the Conservation Technology Information Center's (CTIC) "Core 4" marketing plan. Residue management, buffers, nutrient management and pest management will be promoted nationwide as "Common Sense Conservation". With renewed emphasis on these practices, NRCS hopes to decrease the impact of land management activities on our Nation's natural resources.
Support for the pest management portion of Core 4 and EQIP is provided by the National Agricultural Pesticide Risk Analysis (NAPRA) Project Team. Our Team develops and maintains databases, tools and software that can help assess the potential for off-site pesticide movement, the relative risks of these losses, and the effectiveness of mitigation strategies designed to decrease the loss or reduce the risk.
The NAPRA Team's newest product, WIN-PST (pronounced 'win-pest') is a Windows(r) based pesticide screening tool designed around the Soil/Pesticide Interaction Screening Procedure (SPISP; Goss and Wauchope, 1990). SPISP considers pesticide field half-life, water solubility and Koc to develop the potential for a pesticide to move past the edge of the field or below the bottom of the root zone. A similar soil rating is also developed to estimate the soil's potential to move pesticides. The soil factors used are hydrologic group, depth of the surface horizon, percent organic matter in the surface horizon, and the soil erodibility factor (K factor). Finally, an interaction rating is created to estimate the pesticide loss potential for a specific pesticide-soil combination.
WIN-PST software allows for further evaluation of the soil/pesticide combination and individual ratings, by adding in the effects of management such as reduced rate, banding and crop residue management. Pesticide and soil/pesticide ratings can be further modified by pesticide toxicity. A relative long-term toxicity index for humans and fish has been added to the WIN-PST. This index ranks the long-term EPA human health advisories (Health Advisory: HA or Maximum Contaminant Level: MCL) and long-term fish (Maximum Acceptable Toxicant Concentration: MATC) into four categories: High, Intermediate, Low and Very Low.
The effects of management practices on pesticide movement within WIN-PST can be further refined by the use of NAPRA software to develop local climate and management effects. NAPRA software can also help better determine the effect of pesticide rate reduction, such as the ultra low application rates found with sulfon-ureas, or the effect of multiple rate reducing practices (e.g., banding at a reduced rate).
NAPRA software available from the NRCS NAPRA team has been available since August of 1994. This software is based on the Agricultural Research Service (ARS) agrochemical fate model GLEAMS (Knisel, et al., 1993). NAPRA provides climate based estimates of pesticides loss at the edge of the field and bottom of the root zone. Input parameters include soil properties, pesticide properties, pesticide application rate, method and timing, crop management techniques such as tillage method and timing, and irrigation rate, timing and method. Each cropping scenario is then run through GLEAMS using 30 to 50 years of climate data.
To create a relative ranking of risk, results are expressed as the number of years the average annual pesticide loss at the edge of field or bottom of root zone (runoff, leaching or sorbed to soil particles) exceeds the Human HA, MCL or fish MATC. Results are also expressed as the magnitude of loss in comparison to the toxicity criteria. An average annual loss with a concentration of 21 ppb at the edge of field would exceed the health advisory of a chemical with a HA or MCL of 3 ppb by 7x. The magnitudes of exceedence for each year are summed for the number of years the toxicity value was exceeded.
Comparing pesticide loss to the toxicity of the individual pesticide, allows pesticides to be compared by potential hazard as opposed to just loading. The potential risk from chemicals that are typically combined can be summed to get total risk potential for a suite of chemicals. Although each chemical is routed separately in GLEAMS, this relative ranking method offers a crude but useful overall rating for chemical combinations. Potential synergistic toxicological effects are not taken into account since much of that data is unavailable.
NAPRA is currently being adopted by several states including New York, Michigan, Indiana, Pennsylvania and Texas, to address non-point pesticide loss from farm fields. NRCS NAPRA partners include universities, conservation districts, state regulatory agencies, industry, and non-profit organizations. The ultimate goal is to help farmers choose pesticide management alternatives that reduce hazardous pesticide losses in environmentally sensitive areas.
References:
Goss, D., and R.D. Wauchope. 1990. The SCS/ARS/CES pesticide properties database: II. using it with soils data in a screening procedure. In: Pesticides in the next decade: the challenges ahead. Proceedings of the Third National Research Conference on Pesticides. Nov. 8-9, 1990. Virginia Water Resources Research Center. Virginia Polytechnic Institute and State University. Blacksburg, VA.
Knisel, W.G., R.A. Leonard and F. M. Davis. 1993. GLEAMS: Groundwater Loading Effects of Agricultural Management Systems. University of Georgia, Coastal Plain Experiment Station, Biological and Agricultural Engineering Department, Publication No. 5, 260 pp.
About the author:
Mr. Eric HeskethAddress:
USDA - Natural Resources Conservation Service
National Water and Climate Center
451 West Street
Amherst, MA 01002Phone: (413) 253-4375
Fax: (413) 253-4374
E-Mail: ehesketh@ma.nrcs.usda.govMr. Hesketh is a Soil Scientist with the National Water and Climate Center - Water Science and Technology Team for the USDA - Natural Resources Conservation Service
He received his BS in 1982 and his MS in 1986 from the University of Rhode Island in Plant Science. His Master's Thesis was "Nitrate leaching from turf-grass." He did graduate studies at the University of Massachusetts in Plant Science, investigating the fate of nitrogen in turfgrass. He was also a turf-grass Private Consultant and Computer Modeler investigating nitrogen leaching with GLEAMS (Groundwater Loading Effects of Agricultural Management Systems). He is a GLEAMS Expert and one of the original developers of the National Agricultural Pesticide Risk Analysis (NAPRA) Process and Software. He was a Soil Conservationist with the USDA Soil Conservation Service and is presently the Soil Scientist with the USDA Natural Resources Conservation Service. He is currently working on the development of WIN-PST Software, a Windows
TM-based Pesticide Screening Tool.