While nutrient management is a regulatory requirement in Maryland and Delaware, farmers have been budgeting their nutrients for years.

Maryland initiated a voluntary nutrient management program in 1992 and had nearly 900,000 acres of 1.2 million agricultural acres enrolled by the time the regulatory program began in 1998.

On Dec. 31, 2010, the U.S. Environmental Protection Agency set limits for nitrogen, phosphorus and sediment that could enter the Chesapeake Bay.

To realize these reductions, EPA required Watershed Implementation Plans (WIP) be developed in three phases outlining the steps each state and Washington, D.C., would take to achieve their goals. States divided their goals into sectors including agriculture, wastewater treatment, septic, storm water, and natural or undeveloped land.

The modeled nitrogen load from agriculture for 1985 was 34.3 million pounds per year. By 2010, the modeled load decreased to 23.8 million pounds of nitrogen per year. It has since been reduced to 22.4 million pounds per year. This is remarkable progress, but there is still more work to be done because the Phase III WIP goal is 17.8 million pounds per year.

A large portion of the additional 5-million-pound reduction in nitrogen loads can be achieved with implementation of 4R nutrient stewardship practices.

“Delaware Nutrient Management Commission [DNMC] recognizes the potential to meet our nutrient reduction goals for agriculture not only through increased 4R implementation but also getting farmers credit for the advanced nutrient management practices they’re already doing,” says Chris Brosch, administrator of the commission and member of the DE-MD 4R Alliance Steering Committee.

It can be difficult for states to capture all the 4R practices being implemented on farms. So, the commission is partnering with the 4R Alliance to gather information on 4R practices in Delaware through a survey. It’s important that farmers report all the good work they’re doing in order to receive credit.

What are the 4Rs?

The 4R’s of nutrient stewardship involve applying the right source of nutrients, at the right rate and right time, in the right place. The 4Rs are site-specific; what is right for one farm will likely not be the same on another farm or in another field.

The Delaware-Maryland 4R Alliance was formed in 2015 as a partnership between agribusinesses, conservation organizations, researchers and government agencies with the goal of having every nutrient application on Delaware and Maryland farms be consistent with the 4Rs. The alliance’s focus is increasing implementation of 4R practices to benefit the economic, environmental and social well-being of our region and our farmers. 

Agribusinesses and nutrient management consultants are key partners in this effort. Farmers see them as trusted advisers and often rely on them to make nutrient-related decisions.

By collaborating with agricultural professionals to encourage 4R nutrient stewardship, the alliance hopes that the 4Rs will become the “new norm” for nutrient management in Maryland and Delaware.

Tools for the job

To practice the 4R’s on an operation, the first step is to gather information. It’s important to understand soil type and nutrient analysis, crop need and nutrient removal, historic yield and yield potential, and even hydrology.

“Nutrient management has become increasingly complex, but more integral to a farmer’s crop production plan over the last 30 years,” says Mike Twining, vice president of sales and marketing at Willard Agri-Service and member of the DE-MD 4R Alliance Steering Committee. “Willard Agri-Service embraces the 4Rs; it is a practical thought process that looks at the economic, environmental and social aspects of nutrient stewardship in order to make recommendations that achieve the financial goals of our farmers while also meeting the Chesapeake Bay goals.” 

Willard Agri-Service has embraced adaptive management tools that allow farmers to make in-season decisions based on weather conditions, disease or pest pressure, crop condition, and other variables. This is especially important because what is “right” before planting may not be “right” midseason if conditions have changed.

The right source could be commercial fertilizer, livestock manure, biosolids or compost depending on the needs of the soil. On Delmarva, poultry litter is used frequently due to the high number of poultry farms in the region.

Next, the right rate must be determined. Farmers in Maryland and Delaware are required to test organic nutrient sources to determine the nitrogen and phosphorus content in order to remain within the limits of their nutrient management plan. Applying the right rate from an economic perspective can be difficult within a regulatory nutrient management program, but it is not impossible.

Farmers set a yield goal based on the five-year average for each crop and then must follow land-grant university recommendations for nutrient rate. Farmers can apply different rates to different parts of their field that have more or less yield potential in order to get higher yields while remaining within the regulatory limits.

It is important to recognize that there is no incentive for a farmer to over apply nutrients due to the increased cost and loss of nutrient use efficiency.

Many farmers “spoon feed” their crops by applying necessary nutrients at different growth stages. Applying these nutrients at the right time is important to realize maximum nutrient use efficiency and minimize the chance of loss.

The very wet springs we’ve been experiencing on Delmarva are a great example of this. If a farmer applies all their nutrients in April followed by several large rain events, that nitrogen may be lost and not available to feed their crop. But you can’t lose nitrogen you haven’t applied yet. Therefore, splitting your nutrient applications makes economic, agronomic and environmental sense in most cases. 

Finally, using advanced technology, farmers can apply nutrients at the right place. Farmers know their fields and what areas are more productive than others. Growmark FS has made investments in soil testing technology that allows for higher intensity of soil testing to better inform nutrient placement.

“The use of automated soil testing technology allows us to pull more soil samples faster in order to provide our growers with the best information about their soil fertility at a sub-field level,” says Todd Hunsicker, precision farming specialist for Growmark FS. Applying higher nutrient rates to more productive areas and lower rates to less productive areas can help prevent nutrient loss and improves profitability.

In 2017, agriculture in Maryland and Delaware met its goals for phosphorus and sediment reduction. The Delaware-Maryland 4R Alliance believes that through continued conservation and utilizing the 4Rs, farmers will be able to reach the 2025 targets for nitrogen, too.

Thompson is owner of Thompson Ag Consulting and Eck is programs and public relations director at Thompson Ag Consulting. This article was written on behalf of the DE-MD Agribusiness Association and Delaware-Maryland 4R Alliance.