Crop and Soil Sciences Leads the way in Interface of Nutrient Management and Water Quality

The Department of Crop and Soil Sciences understands the relationship between water quality, nutrient management, and conservation planning while providing solutions to farmers as well as state and federal agencies.

Over forty years ago, Dr. Wendell Gilliam, a renowned professor in the Soil Science Department, measured nutrient losses from fertilized and non-fertilized agricultural fields in the mountains of North Carolina. He was one of the first researchers in the United States to measure the ability of riparian buffers to reduce nitrogen contributions from fields into streams.

Researchers have continued to document riparian buffer effectiveness and provide nitrogen reduction values to the N.C. Department of Environment and Natural Resources. Our department was instrumental in the mid-1990s in developing the nutrient management training required for animal waste operators. During this time, Dr. David Crouse helped develop the training module and worked with producers during certification and afterward to ensure extension materials were provided for continued certification of these farmers. By virtue of these training efforts, nutrients from animal waste used to grow crops are now applied at the appropriate rates, thereby protecting water quality.

As the poultry and swine industries have changed management practices and feed ingredients that directly affect the nutrient content and mineralization potential of animal waste, research and extension programs have continued to ensure that we have a better understanding of the nutrients available in these materials. Given the relatively high phosphorus content in animal waste, especially from poultry, phosphorus losses to surface waters can be a concern as elevated phosphorus concentrations can result in water quality problems in phosphorus-sensitive rivers and streams. Faculty from the Department of Crop and Soil Sciences, along with the NC State Department of Biological and Agricultural Engineering, were responsible for developing the North Carolina Phosphorus Loss Assessment Tool (PLAT) required by the USDA Natural Resources Conservation Service. This index is considered one of the most defensible in the U.S. because it is based on extensive and long-term research developed by researchers in our department.

With Neuse River Basin regulations requiring all sectors, point source and non-point source, to reduce nitrogen coming into the river by 30 percent, Dr. Deanna Osmond led a team that developed the required Nitrogen Loss Estimation Worksheet (NLEW) and later the phosphorus accounting tool (PTAC) for the Tar-Pamlico River Basin. In conjunction with this effort, and working with former soil science faculty member Dr. Steve Hodges, the team developed a farmer nutrient management program to be delivered in regulated river basins by local extension agents. More than 5,000 farmers in North Carolina’s regulated river basins (Neuse, Tar-Pamlico and Jordan) have been trained in nutrient management.

At the national level, Osmond led a team of nine scientists in reviewing thirteen federally funded projects that tried to relate water quality change to conservation practice implementation. This project, known as the National Institute of Food and Agriculture Conservation Effects Assessment Project (NIFA CEAP), identified key lessons that could increase the effectiveness of conservation planning and implementation to protect water quality so that funding is used more judiciously.

These lessons have been presented in the book How to Build A Better Agricultural Conservation: the NIFA CEAP Experience, fact sheets (https://cals.ncsu.edu/crop-and-soil-sciences/extension/publications/), presentations and webinars, as well as through conversations with conservation planning organizations such as Extension and Water Conservation Society, Natural Resource Conservation Services. Additional information can be found at https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/technical/nra/ceap/ws/?cid=nrcs143_014164.

The Department of Crop and Soil Sciences will continue to understand the relationship between water quality, nutrient management, and conservation planning while providing solutions to farmers as well as state and federal agencies.

Written by Dr. Deanna Osmond

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