The Maryland Winter Cover Crop Program: assessing performance

View the project final report

Commodities

• Agronomic: rye, wheat, cover crops

Practices

• Crop Production: catch crops, cover crops, crop rotation, no-till
• Natural Resources/Environment: soil nutrient retention
• Soil Management: green manures

Loss of nitrogen to ground water represents a significant water quality concern. Cover crops are one of the primary mechanisms for scavenging residual fall soil inorganic nitrogen and are being promoted in the Chesapeake Bay watershed to conserve water resources. Beginning in 2005, the Maryland Agricultural Water Quality Cost-Share Program has incentivized farmers to adopt cover crops through direct payments. Payments are structured in a tiered system whereby management affects payment (i.e., species choice, planting date and method, fertilizer source, and field history). State stakeholders are interested in quantifying the success of the program. A study area of farms was identified on the Eastern Shore of Maryland in Talbot, Queen Anne's, and Caroline Counties within the Choptank River Watershed; biomass was collected from 2005-2011 at two points each season: winter dormancy, and prior to cover crop termination. The farms in the study planted cereal rye (Secale cereale L., 23%), wheat (Triticum aestivum L., 46%), and barley (Hordeum vulgare L., 25%), with less than 6% of the study sites planting other cover crops, following corn (Zea mays L., 72%), soybeans (Glycine max (L.) Merr., 25%), or vegetables (3%). These data were used to calibrate vegetative indices for ongoing analysis of satellite imagery (2005-present), which is used to estimate performance of cover crops across those counties. This proposal seeks to assess the agronomic management of cover crops by linking the program enrollment data from the Maryland Department of Agriculture with the estimated biomass as measured using remote sensing techniques.

1) Connect existing datasets to develop a model that predicts cover crop biomass (as estimated from satellite imagery) based on agronomic management (as reported to the Maryland Department of Agriculture by farmers) as a function of thermal time (as calculated from historical weather data).
2) Given the model developed in Objective 1), determine how much the variability in cover crop biomass is due to each agronomic management category relative to landscape variables: soil texture, drainage class, and local topography.
3) Develop a return-on-investment index that scales cover crop biomass to the incentives paid to growers and evaluate each agronomic management category based on performance on this index.