FROM THE FARM REPORT: NEW DRAINAGE RESEARCH FIELD PLOTS OPEN NEW RESEARCH OPPORTUNITIES

Increasingly intense storms and more frequent freeze/thaw events due to climate change are making environmentally and economically sustainable crop production increasingly difficult. To survive the episodic periods of inundation and drought that will accompany these climate changes, farms will need to maximize precipitation infiltration to mitigate the accompanying risks which could result in substantial nutrient and sediment exports and crop failure. To help identify practices that will allow us to achieve these goals, Miner Institute just completed the establishment of an experimental location with twelve tile-drained plots to evaluate the impacts dairy forage production strategies on field hydrology and phosphorus, nitrogen, and sediment losses from a poorly drained soil. This project has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement LC00A01141-0 to NEIWPCC in partnership with the Lake Champlain Basin Program.

In a field just a few miles from our laboratories, twelve 90 ft2 plots were designed and instrumented for year-round sampling of surface runoff and tile drainage. In contrast to the “paired field” study design where we have to monitor two fields for 4-6 years before we’re able to make any real meaningful conclusions regarding the impact of the treatment we’re testing, the larger number of study units (plots instead of fields) allows us to ask and answer research questions on a shorter time scale. The goal is that we will be able to identify promising combinations of practices that will achieve soil health, water quality, and agronomic goals, that we can then implement at our larger and longer-term field-scale sites.

Although considerable efforts have been made in the past 20 years to reduce tributary loading and in-lake levels of P, trends have remained fairly stable in most locations. While legacy effects are likely a major factor in this stasis, there have been relatively few projects in the Northeastern US that have investigated the water quality impacts of soil health practices, including no-till and cover cropping, practices whose usage have increased drastically in the basin in the past 10-15 years. Although many projects have been undertaken to understand how to best implement these practices from an agronomic standpoint, given the unique climate and physiography of the region there’s a lack of a robust body of accompanying research investigating whether the anticipated water quality benefits of these practices developed in other regions are being realized on the dairy farms within the basin.

Research has demonstrated that cover crops in cold climates may have positive impacts on erosion and particulate P reductions, but may increase dissolved P loss, particularly in nonerodable soils. Others have shown no impact on P loss, but significant reductions in N loss from tile drainage. Similarly, eliminating tillage can also have significant impacts on erosion and particulate P losses, but may exacerbate dissolved P loss to tile lines. Finally, while no-till and cover cropping are both practices that can greatly improve soil health, the widely held assumption that improved soil health will lead to beneficial water quality outcomes has not been substantiated in the literature. Yet, the impacts of healthy soils extend well beyond water quality concerns, and these practices should not be considered failures if they fail to improve water quality. Investigating the water quality implications of these practices in our region will provide crucial data to support and verify modeling efforts that attempt to track P movement through the landscape.

— Laura Klaiber

klaiber@whminer.com