Location: Hydrology and Remote Sensing Laboratory
Project Number: 8042-13610-030-027-I
Project Type: Interagency Reimbursable Agreement
Start Date: Jul 31, 2020
End Date: Sep 30, 2023
There is need to assess the environmental effects of poultry house bedding production on the Delmarva. This project will evaluate the effect of the perennial grasses produced for bedding on soil phosphorus and on concentrations of P and N in groundwater and surface waters (nutrient uptake in riparian buffers) through edge of field sampling, and through modeling at the watershed scale. 1. Evaluate the environmental benefit of switchgrass and Miscanthus buffers planted on marginal farmland and near-stream areas including reduction of soil P saturation and reduction of nutrient loss from farmland using field sampling and SWAT modeling. 2. Evaluate the expected improvement in whole-farm nutrient balance (P, N, C) and economic balance associated with on-farm production of poultry bedding material (switchgrass and Miscanthus) compared to the current practice of pine sawdust importation. 3. Evaluate the invasiveness risk of switchgrass and Miscanthus including testing of suitable control methods for termination of Miscanthus stands. 4. Evaluate utility of innovative in situ monitoring instrumentation for real time assessment of ortho-P, total P, and total N in stream waters.
The overall approach will involve strategic sampling and monitoring to assess impacts of switchgrass and Miscanthus production on farm scale nutrient dynamics and assessment of environmental impacts (phytomining of excess soil P, uptake of nitrate and phosphate in ground water) resulting from plantation on marginal cropland, edges of irrigated areas, and buffer areas adjacent to ditches and streams. The data collection is also designed to establish key parameters used in SWAT modeling such that watershed scale assessment of miscanthus and switchgrass production on nutrient exports can be evaluated. The other key component of this work is to assess methods for controlling the potential spread of switchgrass and Miscanthus into non-agricultural ecosystems. including herbicide termination trials, cultural practices, and evaluation of dispersal mechanisms. Data collection: Life cycle analysis: Using Tribbet Farm as a case study, evaluate whole farm nutrient budgets comparing on-farm bedding production versus importation of pine sawdust. Monitor nutrient content of used Miscanthus bedding (P, N, C) and test for increased N:P ratio relative to pine sawdust bedding. Harvest analysis: Monitor Miscanthus harvest (Tribbet Farm) for bedding and for mushroom substrate including yields and nutrient contents (P, N, C). Harvest components will include winter harvest for bedding (above 2ft), winter harvest for mushroom (below 2ft), and fall green harvest for mushroom (higher moisture and nutrient content). Monitor switchgrass harvest (Bluestem Farm) for bedding including yields and nutrient contents, supplementing with data from existing literature. Soil monitoring: Collect pre/post planting tests to monitor soil P content and evaluate the capacity of perennial grass crops to reduce soil P content over time (Tribbet Farm, Mountaire). Groundwater monitoring: Evaluate capacity of Miscanthus and switchgrass buffers to reduce nitrate and phosphorus loss from agricultural fields. Establish cross-border transect of resin lysimeters at two different farms in watersheds. SWAT modeling: Model Miscanthus effects on nitrate uptake and soil P balance. Conduct geospatial calculation landscape modeling of environmental effects at various degrees of implementation. Evaluate extent of marginal and riparian cropland suitable for perennial grass bedding production. Invasiveness assessment: Termination trial and dispersal trial at Tribbet Farm. Evaluate control strategies for Miscanthus and produce data for crop management fact sheet. In situ phosphorus (P) sensors assessment: Three in situ water quality sensors designed to detect concentrations of ortho-P, total P and total N will be installed at existing water quality monitoring sites: the USGS gauge stations located to stream flow on the Tuckahoe Creek, the Upper Choptank reaches with the Choptank River watershed, and a gage outlet for the long-term experimental watershed being monitored by the Pasture Systems and Watershed Management Lab. Periodic grab samples will be taken over a 24-month period to test the accuracy of the in situ measurements.