- Fifth Year Groundwater Project
ARS scientists in Beltsville, Md., are in their fifth year of building one of the most complete data sets in the country on the movement of agricultural chemicals. Researchers at the ARS Pesticide Degradation Laboratory are measuring just about everything involved in the movement of water carrying atrazine, alachlor, and cyanazine herbicides across and under cornfields.
The rain that falls on the fields is measured. The water evaporating from the fields is accounted for. The soil is sampled at 4-inch increments, down to 20 inches, to see how far the chemicals are moving down with the water. The groundwater is sampled from 128 wells drilled to depths ranging from 5 to 36 feet.
And the water that flows off the field is channeled through stainless steel flumes where ultrasonic sensors measure water levels in the flumes. Flowmeters connected to the ultrasonic sensors electronically convert the readings into flow rates and volumes. The meters also trigger automatic water sampling for every 75 or 100 gallons of flow. The samples are analyzed for herbicide content.
With both no-till and conventional till, pesticides aren’t reaching the deepest wells, where groundwater might be used for drinking water. Even when chemicals enter the shallower wells, they are usually well below EPA health advisory levels for drinking water. When levels approach or exceed those levels, they drop back within two or three days as the aquifer dilutes them.
Although the measurements of surface runoff only began last year, preliminary observations have confirmed that no-till can cut surface runoff and accompanying pollution by at least half. The data from this research should help create computer models that can account for regional differences and predict pollution potential nationwide.
Contact Don Comis, ARS, USDA 301-344-2773 for additional information.
- PAC Will Assist in New ACP Practices
Agencies represented on the Policy Advisory Committee of the Working Group on Water Quality pledges cooperation and coordination with the Agricultural Stabilization and Conservation Service as it introduces four new water quality cost sharing practices under the Agricultural Conservation Program.
These new practices are:
- Integrated Crop Management (SP53); which demonstrates the use of crop management measures that encourage efficient use of pesticides and nutrients and demonstrate ecological benefits while maintaining farm income.
- Agricultural Waste Control Facilities (WP4); which can reduce the existing water, land, or air pollution by agricultural wastes. The modified practice is applicable to areas of farmland where agricultural wastes from the farm constitute a significant pollution hazard. A new component was added for composting. This component will assist in addressing the problem of disposal of dead birds.
- Pesticide Containment Facilities (SP55); which are sealed sloping concrete (or equivalent) pads that reduce the potential for contamination of soil, water, and air associated with the mixing, storing, and handling of pesticides. Spillage or rinsate associated with the spray operation drains into a shallow sump or above-ground storage tank for proper disposal according to the pesticide label.
- Constructed Wetland Systems for agricultural waste water treatment (WP6); which uses constructed wetlands for treating agricultural waste water and is based upon using specifically characteristics, such as wetland hydrology and vegetation.
The Soil Conservation Service is providing technical assistance and will issue technical standards and specifications for these practices. For more information contact Jim McMullen, ASCS–USDA, telephone 202/720-6221.
Harry C. Mussman
Chairman, USDA Working Group on Water Quality
Published by U.S. Department of Agriculture’s
Water Quality Information Committee, Patricia Calvert, ES, Chair
