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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Research Project #424726

Research Project: Quantify Potential Nitrate Leaching to Groundwater from Agriculture in Southern Idaho

Location: Northwest Irrigation and Soils Research

2013 Annual Report

1a. Objectives (from AD-416):
The project will be jointly funded by the Independent Dairy Environmental Action League (IDEAL) and Idaho Department of Environmental Quality (DEQ). Separate objectives have not been developed for IDEAL and DEQ. The main focus of this research project is to estimate potential nitrogen losses from the soil root zone in irrigated crop fields and from dairy farms in southern Idaho. The nutrient budgets will be used to identify the relative magnitude of losses from various nitrogen sources so management practices can be appropriately applied to reduce these losses. The specific objectives are: 1. Estimate nutrient budgets for dairy farms in southern Idaho. 2. Estimate nutrient budgets for crop fields in southern Idaho. 3. Use simulation models to estimate nitrogen losses from agricultural sources. 4. Monitor water quality in select springs and wells in southern Idaho.

1b. Approach (from AD-416):
Objectives 1 and 2 will involve data collection from dairy farms and crop fields. We plan to measure nutrient budgets on four dairies and six to eight irrigated fields in southern Idaho. This information will be used to calculate potential nutrient losses and validate simulation models. The Root Zone Water Quality Model (RZWQM) and Integrated Farm System Model (IFSM) will be used in Objective 3 to predict nitrogen losses for various conditions and practices to provide a more comprehensive estimate of nitrogen losses from agriculture in southern Idaho. Water quality monitoring in springs and wells will be used to identify current water quality trends and establish a baseline to assess the impacts of future management practices. Water quality sampling will include isotope analysis to indicate nitrate sources and seasonal impacts of losses from irrigation canals. The total budget for the proposed project is $277,500. The project will be primarily funded by the Independent Dairy Environmental Action League, with $90,000 available in CY2013. Idaho Department of Environmental Quality will fund $25,000 per year for three years ($75,000 total), with funding for years 2 and 3 subject to future appropriations. Anticipated total funding from IDEAL is $202,500 and from DEQ $75,000.

3. Progress Report:
This study expands research in Objective 3 of the parent project by determining nutrient budgets for dairies and irrigated cropland in two southern Idaho counties. The project goal is to identify the potential contribution of agricultural sources to nitrate leaching so practices can be implemented to reduce the impact on water quality. This project began in June 2013. Cooperators have been identified for field monitoring which will begin after crops are harvested in 2013.

4. Accomplishments