Developing a Water Quality Monitoring Protocol for Cranberry Growers to Optimize Best Management Practices for Nutrient Retention

Commodities

Practices

Title: Developing a Water Quality Monitoring Protocol for Cranberry Growers to Optimize Best Management Practices for Nutrient Retention. Compared to most crops, cranberry production requires very large inputs of water for irrigation, harvesting, and crop protection, raising concerns about impacts of nutrients from cranberry drainage on downstream water quality. Cranberry growers have faced increasing scrutiny about water quality impacts, yet very little is known about the nitrogen and phosphorus exports from Upper Midwest commercial cranberry farms, known as marshes. Due to their complex water management, quantification of nutrient losses from cranberry marshes is challenging. Marshes typically receive inputs of surface water and/or groundwater for irrigation and flooding, which may be retained and recycled using reservoirs, or released through surface or subsurface flows to creeks or wetlands. To robustly measure nitrogen and phosphorus inputs and losses to drainage water, we propose to combine collaborative on-farm research with measurements at a unique experimental setting at the Wisconsin Cranberry Research Station. This facility has four cranberry beds constructed over an impermeable liner that restricts groundwater exchange, and surface water is drained through a single outlet, enabling complete quantification of hydrologic nutrient losses. The experimental data will provide the first rigorous measurements of water quality impacts of an Upper Midwestern cranberry marsh operated under best management practices. In addition, we will collaborate with cranberry growers to measure water quality within and among three diverse commercial marshes, and will develop and test a practical sampling method to measure and optimize practices to improve water quality. Commercial marshes were selected to span a range of geographic locations, including an intensive agricultural landscape with nutrient-rich water sources. Comparisons of water inputs and outputs among the commercial marshes allows us to test whether cranberry marshes might be strategically managed to improve water quality, analogous to constructed wetlands. Overall, the project will enable Upper Midwest cranberry growers to assess and improve their management practices with respect to water quality, thereby benefiting the long-term economic and social sustainability of the industry as well as the environment. Project Coordinators (Hall and Atucha) are Extension-funded faculty at UW-Madison and will engage closely with members of the Wisconsin State Cranberry Growers Association through field days, webinars, and extension publications, in addition to producing a peer-reviewed scientific article. Findings will also support development of a module in the cranberry nutrient management training offered by the Wisconsin Department of Agriculture, Trade and Consumer Protection.

Objective 1: Evaluate magnitude and timing of nitrogen and phosphorus losses from cranberry drainage water. 

Objective 2: Develop a protocol for growers to document nutrient inputs in water used for production, nutrient outputs in drainage water, and their relationship to management practices.

Objective 3: Develop extension programming on water quality for the cranberry industry.

Learning and action outcomes: Cranberry stakeholders will learn about water quality interpretation and monitoring protocols for commercial cranberry production. This will inform potential changes in water management and nutrient inputs, improving surface water quality. Outcomes will be evaluated using pre- and post-project surveys.