1a. Objectives (from AD-416):
1. Describe and quantify processes controlling the release of nutrients (N and P) in cranberry farming. 1.1. Characterize temporal and spatial patterns of N and P discharge from cranberry farms. 1.2. Characterize sources and transport pathways connecting N and P to surface water and groundwater. 2. Develop management practices that farmers can use to improve water use efficiency and reduce environmental impacts of agriculturally derived N and P. 2.1. Optimize existing agricultural practices to increase water savings and enhance crop production. 2.2. Develop new technologies and management practices that reduce that transfer of P from cranberry farms to the environment.
1b. Approach (from AD-416):
The research objectives will be carried out using a combination of standard operating procedures and novel instrumentation to measure key physical and chemical attributes of cranberry farms. Our research will transcend spatial scales, ranging from fine-scale microcosm (benchtop) experiments of nutrient leaching, to field scale evaluation of transport pathways, to farm-scale quantification of nutrient loads. Experimental techniques, including parametric statistics and geostatistical analysis, will be used to test the effectiveness of field treatments for reducing nutrient losses, and observational water quality monitoring will offer quantitative insight into sources and transport processes as well as establish better baselines for cranberry nutrient exports. Our research is structured around two research objectives, each of which is divided into subobjectives, consisting of 1-3 focused experiments. These experiments combine field observations with laboratory analyses to develop fundamental knowledge of cranberry hydrology (Objective 1) that guides management strategies for reducing nutrient loss and improving water use efficiency (Objective 2). Our process-oriented research (Objective 1) involves both experimental and observational studies seeking to quantify controls and patterns of nutrient loss. We will conduct microcosm experiments that inform future management strategies for nutrient-loss reduction, and develop a monitoring program for quantifying components of the water and nutrient cycling in cranberry farms. Our applied research (Objective 2) includes experimental studies for developing guidelines with respect to improved irrigation and drainage water efficiency, and reduction of phosphorus loss from farms.
3. Progress Report:
Under objective 1, long-term monitoring of nutrient loss was established on 5 farms, with preliminary results indicating significant spatial and temporal variation in exports of nitrogen (N) and phosphorus (P) from cranberry farms. Compared to N, P export appears to be more spatially and temporally variable, particularly during the harvest flood. Our research shows that the range of chemical behaviors observed in bog soils, which control the transfer of P from soil to water, can likely explain the variation of P export in harvest floodwaters. Under objective 2, research on drainage management and irrigation frost cycling is progressing as expected. New drainage management practices remain poorly developed for cranberry farms, but promise exists in tile drainage as a means of promoting drainage in bog soils. With respect to irrigation management, our research shows that temperature-based cycling (the turning on/off) of sprinklers uses 1/3 less water than conventional methods, equating to a water savings of approximately 2,000 gallons per acre of farm. A new project was also designed to develop P and sediment control agents for cranberry floodwaters. Under both objectives, we continue to grow the East Wareham lab through base and external funds. Two M.S. students joined the lab and are involved in research projects on drainage management and soil hydrology. Additional external funds were secured to support summer field staff and a new project on the agronomic and environmental benefits of controlled released fertilizers. Additionally, a research proposal was submitted to secure funding for a postdoctoral researcher to develop gypsum as a P and sediment control agent in cranberry floodwaters. We have also developed strong ties with local growers, leveraging their staff to assist in the field sampling. Progress is monitored through periodic site visits, conference calls, and emails with project and university collaborators.