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Estimating Nitrous Oxide Reductions from Nutrient Management in the Chesapeake Watershed

Nutrient Management - CBF

Project Timeline: Concludes Summer 2014

Enhanced nutrient management approaches are being promoted in the Chesapeake Bay region for their benefits to water quality and also because of the potential cost-savings for agricultural producers.  An additional benefit is that these approaches can also lead to reductions in the emissions of nitrous oxide, a very potent greenhouse gas.  Nitrous oxide (N2O) is produced in the soil predominantly by microbial processes; less applied nitrogen results in fewer N20 emissions. Several of the existing voluntary carbon registries will accept “carbon credits” generated by the N2O emissions reductions associated with the implementation of nutrient management.

The goal of the project is to develop and implement a greenhouse gas tool for estimating nitrous oxide reductions from nutrient management in the Chesapeake Bay watershed. The tool is known as the Denitrification-DeComposition (DNDC) model -  a peer-reviewed and tested simulation model of carbon and nitrogen biochemistry in agro-ecosystems that is accepted by the American Carbon Registry for certification of carbon credits. This project will result in a region-specific, user-friendly version with the goal of reducing some of the technological and financial barriers to certifying carbon offset credits generated by nutrient management projects.

We will use the tool to estimate the nitrous oxide emissions benefits of three different nutrient management approaches, tested in three locations: soil testing/adaptive management on corn farms in South Central Pennsylvania, manure injection in western and central Maryland, and variable rate technology (i.e., GreenSeeker) on grain farms in Virginia’s Onancock Creek watershed. This approach will allow us to compare and contrast these approaches in terms of greenhouse gas benefits, fertilizer savings, and obstacles to greater implementation. Eventually the resulting carbon offset credits will be certified and registered in the American Carbon Registry.

Despite the potential for cost-savings to agricultural producers (due to lower fertilizer costs), of implementing enhanced nutrient management, these approaches are, by no means, “business as usual.”  The technologies require new capital investments by farmers, use of complex technology, and many farmers fear that the new practices will result in crop yield reductions. Ultimately, we hope to encourage adoption of enhanced nutrient management techniques by Chesapeake Bay region farmers by facilitating the process by which they can participate in, and financially gain from, carbon offsets markets.

The project is leveraging dollars from a partnership CBF has with Washington Gas Energy Services (WGES) and Sterling Planet (SP) whereby WGES and SP are donating some of the proceeds from the sale of carbon offsets to WGES customers into a Carbon Reduction Fund (CRF) that CBF is managing. The purpose of this Fund is to implement projects, primarily with agricultural producers, which generate certified carbon offset credits while also reducing water pollution to the Chesapeake Bay. This innovative fund presents a tremendous opportunity for the Chesapeake Bay region’s agricultural producers to participate in the nascent carbon markets. It has also highlighted some of the challenges of certifying credits generated via agricultural projects, some of which the CIG project hopes to overcome.

Partners:  Environmental Defense Fund; Maryland Department of Agriculture; Virginia Tech Extension; DNDC Applications, LLC NRCS ARS; and EcoFor LLC.


Specific objectives of the project include:

  • Implement enhanced nutrient management on approximately 6000 acres of cropland (mostly corn and some wheat) on 30 farms. The project includes 2 growing seasons.
  • Calibrate and validate the Denitrification-Decomposition (DNDC) model for cropping systems in the Chesapeake Bay watershed.
  • Create a more user-friendly version of DNDC model by developing the underlying regional soil and climate databases and a user-friendly interface.
  • Apply the DNDC model to advanced nutrient management projects on participating farms, with EQIP-eligible producers, to determine the potential for carbon offset credits.
  • Prepare and submit a Greenhouse Gas Project Plan to the American Carbon Registry (ACR).
  • Conduct three workshops to educate farmers and technical service providers on the pilot project, carbon markets and potential use of the ACR protocol and DNDC model.
  • Achieve third party certification and validation of credits.
  • Compare and contrast the greenhouse gas benefits and implementation costs of three different nutrient management approaches - manure injection, adaptive nutient management and GreenSeeker (variable rate nitrogen application) in three different states in the Chesapeake Bay region.

We estimate roughly 400 metric tons of carbon dioxide equivalents will be generated. This number does not include benefits associated with GreenSeeker (variable rate nitrogen application) in VA because implementation of this practice will be paid for by another grant, and we are concerned about additionaility.

Project Summary

The goal of the project is to develop and implement a greenhouse gas tool for the Chesapeake Bay watershed with the goal of reducing some of the technological and financial barriers to certifying carbon offset credits generated by nutrient management projects. 

Successes & Challenges

Our project involves estimating the nitrous oxide emissions associated with three different nutrient management approaches – variable rate technology, manure injection and adaptive management. A combination of grant funds and private (Carbon Reduction Fund) dollars are paying for the implementation of the latter two approaches. 

Consequently, one of the project objectives is to get the carbon credits resulting from the implementation of these two practices, registered in one of the voluntary carbon registries, most likely the American Carbon Registry. Two of the obstacles we encountered early on were related to the data requirements of the DNDC model and for third party verification of any associated carbon credits. Below is a summary of what transpired, lessons learned and our thoughts on ways to address these issues in the future. 

One of our implementation partners, Environmental Defense Fund (EDF) notified us shortly after receiving the grant that one of their key partners was leaving the University of Delaware, and asked if they could move the project from Maryland to Virginia. In Virginia, EDF planned to partner with the Virginia Grain Producers Association (VGPA) and Virginia Tech extension. These 3 partners had an ongoing project in Virginia to do adaptive management on roughly 80-90 farms. Currently, the farmers are not paid to participate, but receive free technical assistance and data and soil analyses needed to help them do a better job of nutrient management.

EDF was planning to use the grant to expand the program for 2 more years in VA. They presented our project to their current participants at their end of year meeting. The feedback they received at the meeting was:  5 years of historic information on nutrient management and yields was do-able, but difficult.The concept of third party verification hurt the farmer’s sense of integrity e.g., why don’t people trust us? Also, we were not clear of what third party verification might entail, so the uncertainty (would it take 5 hours or 5 minutes?) was problematic.  In the end, the VGPA Board voted at a subsequent meeting not to participate.

EDF moved the project to Lancaster and Chester counties in PA. They have worked with a local partner, "Team Ag" to successfully recruit 5 farmers to particpate in the program this spring. They are currently in the process of collecting the baseline and project information from these farmers. These farmers have also agreed to give any resulting carbon credits to CBF and to participate in third party verification, if necessary.

As an aside: Farmers in the Bay region are feeling very much under the “microscope” lately because of the Chesapeake Bay TMDL and the focus on achieving pollution reductions of nitrogen, phosphorus and sediment from all sources, including agriculture. In addition, the Federal Farm Bureau, Pennsylvania Farm Bureau and other national agribusiness groups have sued EPA over the Bay TMDL. CBF is one of several plaintiffs that have intervened in that case, on behalf of EPA. So it is likely that compared to other areas, Chesapeake Region farmers are very sensitive, especially in terms of feeling that they are not trusted.  Bottom line:  What was being proposed to the farmers was basically the same project, only with more hoops and so was viewed as being more trouble, with no extra value to them.  

In Maryland, our partner, MDA, had some similar concerns about the potential effects of the data collection requirements and third party verification on farmer recruitment. In this case, as with the EDF project in VA, farmers that will be likely participants in our project, are those that in previous years had received cost-share for implementing manure injection/vertical tillage. This year, the grant funds will supplant the state cost-share, yet the requirements for participation will change. Even though we offered a higher cost per acre, no farmers enrolled in the program in spring 2012. 

In Virginia, to date, our partner, VA Tech has enrolled 500 acres under GreenSeeker. We are hoping to dramatically expand these acres by using the additional EQIP dollars and targeting them to farmers that want to use GreenSeeker and will share the information necessary to run the DNDC model.

Project Partners

  • Suzy Friedman
    Environmental Defense Fund [email protected]
  • Mark Reiter
    Virginia Tech
  • John Rhoderick
    Maryland Department of Agricultre
  • Bill Salas
  • Gordon Smith
    EcoFor, LLC
  • Alden Hathaway
    Sterling Planet
  • Michel Cavigelli
    USDA -ARS - Beltsville

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