Location: Soil and Water Management Research2017 Annual Report
1. Develop irrigation and drainage strategies in the North Central United States to protect water and soil resources a. Determine the potential of amendments to mitigate leaching and contamination of groundwater from agricultural operations. b. Identify materials and designs that will maximize contaminant removal from subsurface drainage water. 2. Identify and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources. a. Evaluate the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. b. Identify and test management practices to reduce reactive nitrogen leakage from dairy farming systems. c. Determine the impact of perenniallizing practices on the nutrient and water balances of corn/soybean systems. d. Determine the influence of management practices and water conservation strategies on water use and the occurrence and fate of contaminants in urban agriculture.
Protecting the integrity and supply of our water resources is one of the most important issues we will face this century and therefore the foundation of our project’s objectives (objectives 1 and 2). Our research approach requires laboratory to field scale investigations focusing on two strategies, prevention and mitigation. With the prevention strategy we will identify and understand the fate of potential water contaminants (e.g. agrochemicals: fertilizer, pesticides; anthropogenic compounds) and develop practices to prevent or minimize the off-site transport of contaminants from their site of application or point of origin. For instance, we will evaluate the fate of biochar and its efficacy as a soil amendment to reduce the leaching of agrochemicals (subobjective 1a), management practices to minimize agrochemical transport with storm runoff from low-input turf (subobjective 2a.1), and the occurrence of contaminants in urban agricultural systems and the influence of water conservation and management practices on contaminant availability (subobjective 2d). In addition, we will determine the influence of perennial cover crops and the use of different irrigation and nitrogen rates to reduce transport of nutrients with runoff and drainage from row crops (subobjective 2c). Model simulations will also be used to predict nitrate loads in tile drainage from a concentrated animal feeding operations (CAFO) dairy and simulate the efficacy of alternative practices to reduce loads (subobjective 2b). In circumstances where contaminants are transported off-site with overland flow or leaching, mitigation strategies will be taken to remove contaminants from runoff and tile drainage before they reach surface waters or groundwater. Mitigation approaches include plot-scale studies to identify optimal buffer size and management of low-input turf for the removal of contaminants transported with runoff (subobjective 2a.2), while field and modeling experiments will identify the most effective bioreactor design and materials for removing nutrients from subsurface drainage water (subobjective 1b). Our multidisciplinary team and the interrelationship of our project subobjectives within and across these strategies will make progress towards the national goal for improved water resource security.
Objective 1a: Volunteers have been initially solicited and initial citizen science trials have been started. Additional volunteers will continue to be solicited into next fiscal year. Project website will be established by the end of the year (hypothesis 1a.1). Laboratory equipment and method development has been acquired for biochar aging and pesticide transport experiments (hypotheses 1a.2 and 1a.3). A new collaboration has been established with the Spanish Research Council Institute of Natural Resources and Agrobiology in Seville, Spain. Additionally, a graduate student from Brazil visited the St. Paul, Minnesota laboratory to collaborate on soil type × climate impacts on biochar pesticide sorption. Objective 1b: The first of three flow regimes of the denitrifying bioreactor laboratory experiment to maximize nitrate-N removal (goal 1b.1) is set to begin in mid-July 2017 and be completed by September 1, 2017. The set-up is operational and currently in pre-test mode. Flow and water quality data are being collected from the three-bed field bioreactor in Faribault County, Minnesota (hypothesis 1b.2). Presentation to the local Drainage Authority of flow and nitrate-N load data from the first year of operation is planned for August 1, 2017. Objective 2a: Establishment of low-input turfgrass plots began with laser leveling the research area to a consistent slope of 5±1% from east to west. This entire area was seeded with a mixture of 40% ‘Beacon’ hard fescue, 20% ‘Radar’ Chewings fescue, 20% ‘Shoreline’ slender creeping red fescue, and 20% ‘Quatro’ sheep fescue. Starter fertilizer was applied and the area was periodically irrigated to maintain surface moisture throughout germination and establishment. Runoff gutters, flumes, flow meters and automated samplers were installed (hypothesis 2a.1). A literature search is underway to identify contaminants of concern (hypothesis 2a.2) and extraction and analysis methodologies (hypothesis 2a.1 and 2a.2) to be utilized in the low-input turfgrass runoff studies and the low-input turfgrass filter strip/buffer research. Objective 2b: We took part in discussions with other ARS locations in DAWG to develop coordinated research to reduce N losses from dairy systems. Calculation of subsurface drainage nitrate-N and dissolved phosphorus loads will be completed along with analysis of soil N and P at four depths over 10 sample years. A manuscript to compare nitrate-N drainage concentrations and losses on fields with fall manure injection versus in-season fertigation (hypothesis 2b.1) has been started. Validation testing is well underway for the Integrated Farming System Model, which is being used to test strategies to reduce reactive N leakage from dairy systems by 20% (hypothesis 2b.2). A critical test of the model’s predictions of drainage nitrate-N losses under manured systems (tile drained and non-tiled) is being conducted on nine sites encompassing 48 site-years. Objective 2c: Established new field experiment to address the hypothesis that perennializing practices will reduce reactive N loss from corn/soybean systems (hypothesis 2c.1) Objective 2d: A literature search has been initiated to identify potential contaminants of concern in urban environments and method development is in progress for the extraction and analysis of contaminants (hypotheses 2d.1, 2d.2). Several innovative urban agricultural systems have been identified and are under consideration for research pertaining to hypothesis 2d.3. Communication with potential collaborators and identification of research locations has been initiated (hypothesis 2d.1, 2d.2, 2d.3).