Effect of recurring flooding on greenhouse gas emissions, soil C and N contents and forage quality in grazing and hay fields.
In OH, forage in areas prone to flooding is planted for grazing and as a tool to mitigate nutrients loss in environmentally sensitive areas. At the same time, generating more information on the performance of pastures in these areas is important to achieve increased productivity for farmers. In grazed pastures, over 80% of phosphorus (P) and nitrogen (N) is returned to soils by grazing animal manure deposition, creating hot spots of nutrient concentration, and consequently nutrient losses to air and water. In OH, grazed pastures are usually located in hilly and flood prone areas that create critical source areas for nutrient loading to freshwater systems. On the other hand, in the Western Lake Erie Watershed region of the state, croplands are predominant on more level land. In that region, sediment, nutrients and animal manure are transported via surface and subsurface water movement from the field to the watershed and eventually, Lake Erie. The establishment of forage cover on cropland near the environmentally sensitive areas is encouraged through the Ohio Working Lands Buffer Program. The program allows forage harvest and removal, with limited grazing. Through the lens of increasing concern for water quality and climate change impacts, alternatives to reduce nutrient losses to air and water are clearly needed. Therefore, the impacts on air and water contamination must be examined and quantified to allow for solid science-based recommendations to the farming community. Our objective is to understand the effects of flooding on greenhouse gas emissions from soils, C and N contents and forage quality in flooded and non-flooded grazing pastures and hay fields, in southern and northwestern OH. The main outcomes are a baseline understanding of recurring flooding on grazing systems, to allow future identification of strategies to increase systems resilience and resistance to flooding, and identification of potential the net environmental impacts of the use of forage crops as a buffer for nutrient losses.
Project objectives from proposal:
The overarching outcome is to provide lacking knowledge regarding effects of recurring flooding on greenhouse gas (GHG) emissions from soils, soil and forage characteristics, and productivity of grazed and hay pastures, when compared to non-flooded fields. This project will focus on grazing systems under flood and non-flood areas (Scenario 1), and the use of forage crops for hay, as a buffer for nutrient losses (Scenario 2). The outcome of Scenario 1 is the definition of baseline for the flood impact on air, soil, and pasture. Once we know these impacts, we will identify and suggest strategies to increase system resilience and productivity.
The outcome of Scenario 2 will be the net environmental impact (balance between environmental impacts, such as GHG emissions, and benefits such as soil C and N contents, forage quality and productivity) of the use of forage crops as buffers for nutrient losses. This information will be useful for a holistic evaluation of the Ohio Working Lands Buffer Program (OH Department of Agriculture), that supports the implementation of forage crops to reduce P losses to water in environmentally sensitive areas (i.e. under flooding). This will allow early adjustments of the Program in order to decrease environmental impacts and increase farmer adoption.
This project will provide deep understanding about management of flood prone areas, a common problem in OH and in the NCR. Farmers will then be able to make a well-informed decision on how/if to use flood-prone areas in their farms, reducing unnecessary costs and increasing profitability.