Report analyzes inputs, outputs of ag nutrients
Citing gaps in available data, a group focused on assessing a mass balance of agricultural nutrients on Delmarva announced it could not determine a reliable final value.
The newly renamed Delmarva Land and Litter Collaborative, formerly Delmarva Land and Litter Challenge, issued a Mass Balance Methods Report Nov. 19 that outlined its process for evaluating the agricultural nutrient inputs and outputs on Delmarva and gave recommendations on what data is needed for a final mass balance figure.
“The intent of releasing this report is to share information about methodology and lessons to inform future mass balance work on the Delmarva and elsewhere,” the group said in the report.
Determining a mass balance would essentially answer the question of is there more or less poultry litter generated on Delmarva than its cropland can utilize.
“This is a question that agriculture and the environmental community has debated for years,” Kristen Hughes Evans, DLLC vice chairperson and executive director of Sustainable Chesapeake, said in phone call with media. “The answer to this question is essential to addressing other questions like how much poultry litter is generated on Delmarva and therefore how much phosphorus and nitrogen is available for alternative uses.”
Formed in 2015, the DLLC is a diverse group of stakeholders seeking environmentally sound approaches to chicken farming. It’s 26-member steering committee is comprised of individual farms, environmental, conservation and farming groups from Delaware, Maryland and Virginia.
The methods report comes after three years of collaborative research among representatives from academia, agriculture industry, state and federal government agencies and environmental non-profits. The process required a consensus agreement on every dataset, assumption and recalculation and on the outset, the group decided it would only release its results if the full DLLC steering committee had consensus in support of the final product. Ultimately, the methods report said consensus could not be reached on three items and a final value was not released.
The report cited a lack of consensus around assumptions of soil phosphorus levels, nutrient application rates and what data to use for yields goals.
In the media call, Evans said unavailable data on soil phosphorus levels was the biggest challenge in reaching consensus.
“We don’t have good public information about that. The assumptions you make about that have an outside influence on the results of the analysis,” she said. “We were not comfortable as a whole with making assumptions about that number given the influence it had on the final outcome.”
The methods report explained the methods and data the DLLC used and listed seven recommendations as additional data needs to complete a mass balance study including integrating new Ag Census data, comprehensive poultry litter transport data by county and soil phosphorus data by county.
The report also made recommendations for conducting future mass balance studies on Delmarva and for undertaking collaborative projects with a diverse group of stakeholders.
Evans said other researchers in the region are working to include DLLC methods and recommendations into their own mass balance analysis on Delmarva.
“We are hopeful that the next iteration of this process will create a scientifically-defensible peer-reviewed mass balance report that will serve as a basis for policy making on the Delmarva,” Evans said.
The DLLC also announced the release of its online storyboard educational tool, “Exploring Chicken Farming on Delmarva,” which uses reliable and unbiased data to illustrate the changes and characteristics of chicken farming on Delmarva over the past 30 years.
Available at the DLLC’s website, delmarvalandandlitter.net, the storyboard covers population changes, poultry production and environmental management.
“We hope the tool and it’s findings help shed light on questions frequently asked about chicken production on Delmarva,” said Kurt Fuchs, DLLC chairman. “We hope that this creates common ground for future discoveries.”
Fuchs said going forward, the DLLC will continue to promote its stakeholder diversity through policy discussions and look at the merits of conservation drainage as a best management practice and explore issues and solutions in manure storage.
“We feel that the group’s real value is in having conversations, sharing perspectives and finding new solutions together,” Fuchs said.
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