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You are here: Home / About WQIC / Working Group on Water Resources / Water Quality: A Report of Progress / Data and Evaluation  Printer Friendly Page
About the Water Quality Information Center
Working Group on Water Resources

Water Quality: A Report of Progress

Published Sep 1997

Data and Evaluation


  • To develop, analyze, and report timely and statistically reliable data on the aggregate levels of use and composition of pesticides, fertilizers, and related inputs.
  • To analyze the expected environmental improvements and economic effects of a comprehensive program of research, education, and technical assistance for reducing potential water quality problems in agriculture.
  • The pesticide data program is conducting 2 data collection efforts.

Chemical Use Surveys - Chemical Use Surveys are being conducted by the National Agricultural Statistics Service and the Economic Research Service in several cycles, covering the major field crops, vegetables, and fruits. The surveys were started because of lack of current, reliable data, concerns over chemical residues affecting ground and surface water, and concerns over chemical residues on food crops.

The surveys provide a data base for trends in usage. Data from the surveys are used to develop statistical estimates of fertilizer and pesticide use on major field crops and to provide a research data base to analyze production inputs and practices associated with chemical applications. These data also significantly contribute to Situation and Outlook reports and other USDA research.

The survey of the major field crops in major producing states is conducted every year. The vegetable chemical use and economic survey, begun in 1990, is conducted semiannually and covers 25-30 vegetable crops. The fruit chemical use survey is conducted semi-annually (starting in 1991) and covers 25-30 fruit and nut crops.

Year-to-year changes have occurred in the crops and States which were surveyed. The States selected for the survey are those which represent the largest proportion of the national acreage. These States may change as production shifts among States.

A target sample size is selected for each crop to provide a sufficient number of completed interviews to make State-level, statistically reliable estimates of treated acres and application rates for most commonly used pesticides. Fields for this survey are selected using a multiframe, stratified sampling procedure.

Trained staff conduct personal interviews with farm operators to collect data about the selected field. The interviews are scheduled late in the growing season so that operators can provide information covering the full growing season. Interviews for wheat are generally conducted after. Response frequency is generally over 75 percent.

Data gathered in all the surveys include types, application, timing, and amounts of fertilizer, pesticides, and other chemicals. Data are also obtained on irrigation, cropping, and production practices; and for a subset of sample points, economic information on the farm unit is collected.

In 1993 NASS conducted a survey of subscribers to its chemical use publications. Respondents overwhelmingly indicated that the chemical use reports prepared from the survey data are helpful. Respondents found the data useful for determining trends in chemical use, rates of application, and methods of application. Respondents consider the data to be reliable and useful for making market and policy decisions. Some suggested expanding coverage to additional crops and States, and publishing statistics for infrequently used products.

Chemical use data from each survey are reported in Chemical Usage Reports prepared by NASS. Data from the surveys are also used to support policy research. Survey data have been used in an assessment of cotton production impacts on water quality; the adoption of IPM on field crops, vegetables, fruits and nuts; and an assessment of the commodity program's influence on chemical use in corn production.

Area Study Surveys - The Area Study survey uses a cross-sectional, multiple-frame sampling approach to collect data on chemical use and other production practices for particular geographic areas. These surveys are being conducted in areas where the U.S. Geological Survey is conducting extensive monitoring, modeling, and assessment of water resources as part of its National Water Quality Assessment (NAWQA) program. Together, this information will enable us to examine the effects on water quality of on-farm agricultural chemical use and production practices. USGS is helping us establish the land use-water quality linkages.

Area Study surveys were carried out in 12 NAWQA study regions. These study regions were selected on the basis of the presence of agricultural cropland, significance of agrichemical use, the presence of soils that leach, and a significant water quality demand. The study areas are: Albemarle-Pamlico Drainage, Central Columbia Plateau, Central Nebraska, Iowa-Illinois, Lower Susquehanna Basin, Mississippi Embayment, San Joaquin-Tulare, Southern Arizona, Southern Georgia, Southern High Plains, Upper Snake River Basin, and White River Basin. ERS and NASS have gathered chemical use and farm practice information to be correlated with soil, land use, water quantity and quality, and other hydrologic data. Some of the data collected include a 3-year land use history, including crop history and planting date, 3-year chemical use history irrigation, tillage, cultivation, and conservation practices, and use of non-chemical practices to control pests.

All of the Area Study surveys have been completed. No new surveys are planned. Survey data are supporting a number of research projects. Data have been used in an economic assessment of nitrogen testing for fertilizer management, in the development of an economic model of the agriculture sector in Nebraska, and in an evaluation of the Water Quality Incentive Projects.

Last Modified: Feb 25, 2011

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