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Monitoring Land Treatment in Agricultural Nonpoint Source Pollution Control Projects
The Rural Clean Water Program Experience

Changes in water quality resulting from the implementation of nonpoint source (NPS) pollution controls can be determined by monitoring the particular water resource of interest. Water quality monitoring, along with a simple inventory of land use and land treatment (implementation of best management practices), is usually sufficient in most agricultural NPS projects, especially if the intent of a water quality project is merely to document water quality improvements. However, monitoring the water resource alone is insufficient to document a cause-and-effect relationship between changes in water quality and changes in land treatment or land use. To ascribe changes in water quality to land treatment and land use, it is often necessary to intensively monitor (track) and document both changes in water quality and changes in land use and land treatment over an extended period of time (at least four to eight years). Land-based data requirements include detailed, timely, and site-specific information about land treatment practices and land use changes.

Few agricultural NPS pollution control programs before the Rural Clean Water Program (RCWP) attempted to correlate water quality changes with the installation of land treatment practices and land use changes on a watershed scale (Gale et al., 1993). In several of the 21 RCWP projects, efforts were made to correlate land treatment with water quality changes.

Land Treatment Monitoring in the Rural Clean Water Program

One of the objectives of the RCWP was to document that NPS controls can reduce pollutant loss from agricultural land. Only a few RCWP projects participated in land treatment monitoring at a level sufficiently detailed to correlate land-based activities with water quality changes. Personnel in these projects had to design experimental protocols for correlating land treatment practices with water quality data. In addition, many of the technical tools (personal computers, geographic information systems, database software) that facilitate detailed land treatment and land use data analysis only became commercially available or affordable during the period of the RCWP (1980-1995). Many of the lessons that were learned about land treatment and land use monitoring during the RCWP are presented in this fact sheet. However, the science of land treatment monitoring is in its infancy and can be expected to continue to evolve for the foreseeable future.

Land Treatment Monitoring Strategy

A land treatment and land use monitoring strategy should specify the variables to be monitored, the monitoring frequency for each variable, and the landscape scale of each monitored variable.

Variable Selection


The land-based variables selected for monitoring should correspond to the identified water quality problem and should include static, temporal, and spatial variables. For example, if sediment deposition caused by cropland erosion is the water quality problem, the variables should include position of the field relative to the water resource, soil type, field slope, acres under various cropping systems, soil conservation practices, and timing of tillage activities. When the water quality problem is caused by runoff of nitrogen, rates and timing of commercial fertilizer and manure applications should be tracked.

Sample Frequency


The frequency with which a variable should be monitored depends on the specific variable and its characteristics. In general, monitoring should take place at the same time that land use or land management changes occur. For example, each fertilizer application during a given production season should be recorded by field. The number of applications will depend on management decisions made by the individual farm operator. Crop type should be tracked on a yearly basis.

Landscape Scale


The appropriate landscape scale for each variable will be determined by the pollutant being monitored and its source. Land-based activities located within the delineated critical area (the land area contributing most to the problem) should be closely monitored for both project participants and non-participants. For example, since the Oregon RCWP project watershed was very large (363,520 acres), and the pollutant of concern was fecal coliform, the scope of the land treatment monitoring focused exclusively on the dairy farm operations that constituted 6% of the watershed and 100% of the critical area. Data should be collected by subwatershed in order to match land use and land-based information with the water resource of concern.

Data Collection

Careful data collection is essential to ensure accuracy. There are several ways to collect land-based data and the collection method should be determined based on the intended use of the data as well as the extent of financial and human resources available.

During the RCWP, most of the land-based data were collected by the U.S Department of Agriculture (USDA) - Natural Resource Conservation Service, Consolidated Farm Services Agency, and Extension Service as part of the agencies' annual reporting. These aggregated data included information on the types of crops produced, number of acres grown, number and types of animals in the watershed, and soil and water conservation practices installed under federal cost-share programs. Additional data on best management practices installed or utilized were collected for each RCWP project by agency personnel. Although this information provided an overall perspective on land treatment activities and land utilization, by itself the data were not sufficient to correlate changes in land-based activities and water quality.

Consolidated Farm Services Agency (CFSA) reporting formats allow description of annual aggregate agricultural information by county, but are simply not detailed enough to support reliable correlations between land-based activities and water quality changes that occur on a seasonal basis. The Idaho RCWP project enhanced the use of CFSA data by compiling the information contained in CFSA annual reports on a drainage basis by season. However, the drawback of this system was that detailed land use and management data were not available for landowners who did not accept cost share payments for best management practices (those who did not participate in CFSA-administered programs).

Producer log books, called field logs, are useful tools for data collection. Using field logs for data collection increases the precision of the land treatment information. The quality of data collected through field logs, however, is dependent on each individual's ability and desire to use the field log. The Vermont RCWP project (one of only two RCWP projects that collected detailed land treatment data using log books) distributed field logs to all producers in a selected watershed, regardless of their project participation status. Although frequently difficult to obtain, land use data from non-cooperators within the watershed can provide valuable data to explain water quality trends as well as sociological information from farm operators who have decided not to participate in a project. An added advantage of using field logs is that further information can be obtained by project personnel who talk directly with farmers when collecting the field logs.

Land-based data can also be collected through personal interviews. Although the necessary data may be difficult to obtain through interviews with producers, the effort should be made. In the Vermont RCWP project, researchers found that two visits per year, timed during less busy seasons, were more effective than one annual visit at eliciting detailed land treatment information from farm operators. If a project is small enough, detailed land-based activity data can be collected by project personnel. All eight dairy farmers located in the lower Snake Creek drainage basin participated in the Utah RCWP project. Because it was feasible for project staff to visit this small number of farms frequently, project personnel remained well informed about land-based activities on all of the farms.

Aerial photography can be used to collect data about land use. Photography must be supplemented with additional information about land-based activities, such as fertilizer placement.

Sometimes direct observation is necessary. In the Alabama RCWP project, a spike occurred in the fecal coliform data for one of the tributaries to Lake Tholocco. Project personnel could not account for the spike on the basis of the land uses that surrounded the tributary. After walking along the tributary, project personnel discovered that the source of the fecal coliform was a new beaver colony. Without direct observation, project personnel would not have been able to identify the source of the pollutant.

Data Storage, Analysis, and Reporting

In the early 1980's, most land-based data were stored on paper and in files. The majority of data analyses and reporting was done manually. Personal computers have now simplified data storage, analysis, and reporting. A computerized spreadsheet or data base facilitates effective storage of data on a farm field and watershed or subwatershed basis. However, handwritten file sheets should be kept as back-up. Summaries of important land-based information, such as acres under conservation tillage within one-half mile of a stream, can be readily computed and reported using data base software. During the later stages of the RCWP, the Natural Resource Conservation Service introduced CAMPS, its computerized data base system, which significantly reduced the work associated with data storage, retrieval, and reporting.

Computerized data bases and systems that synthesize spatially referenced data (geographic information systems) facilitate representation of land use practices and tracking of best management practice implementation; data accessibility, analysis, and presentation; and aggregation of land treatment and land use data. Geographic information systems are useful tools for data display, analysis, and reporting. A few RCWP projects (Idaho and Vermont) digitized project data to make possible spatial representation of land treatment and land use practices over time.

For smaller projects, such as the Utah RCWP project, which included only eight dairy farms, spatially and temporally referenced data can be obtained manually. Large-scale maps can be utilized and updated regularly for spatial and temporal referencing of BMPs.

Key Points of Monitoring Land Treatment

Land Treatment Monitoring Strategy
Data Collection
Data Storage, Analysis and Reporting

Reference

Gale, J.A., D.E. Line, D.L. Osmond, S.W. Coffey, J. Spooner, J.A. Arnold, T.J. Hoban, and R.C. Wimberley. 1993. .Evaluation of the Experimental Rural Clean Water Program National Water Quality Evaluation Project, NCSU Water Quality Group, Biological and Agricultural Engineering Department, North Carolina State University, Raleigh, NC, (published by U.S. Environmental Protection Agency) EPA-841- R-93-005, 559p.


Written by

Deanna L. Osmond, Jean Spooner, and Daniel E. Line

Water Quality Extension Specialists

NCSU Water Quality Group

March 1995




North Carolina
Cooperative Extension Service

NORTH CAROLINA STATE UNIVERSITY
COLLEGE OF AGRICULTURAL & LIFE SCIENCES

Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.

This fact sheet is one of a series of Rural Clean Water Program Technology Transfer fact sheets prepared by the NCSU Water Quality Group with support from the Extension Service, U.S. Department of Agriculture (Cooperative Agreement No. 93-EXCA-3-0241).

Copies of the fact sheet series may be requested from: Publications, NCSU Water Quality Group, Department of Biological and Agricultural Engineering, Box 7637, North Carolina State University, Raleigh, NC 27695-7637, Email: wq_puborder@ncsu.edu, Fax: 919-515-7448.