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More than 20 percent of New York milk assessed for its nutrient footprint.

Cornell University’s Nutrient Management Spear Program (NMSP) is helping farmers evaluate their nutrient use through the Cornell whole-farm nutrient mass balance (NMB) tool. This project, led by NMSP Research Associate Olivia Godber, is focused on guiding farmers toward their “Optimal Operational Zone” or “Green Box,” the sweet spot where milk production efficiency is high and environmental impact is low. Read on to learn how this program supports farmers and to find out how to join.  

When the NMSP team calculates a whole-farm NMB, they evaluate nutrient use on farms using a software tool that targets three critical macronutrients: nitrogen (N), phosphorus (P) and potassium (K). These macronutrients, referred to holistically as NPK, are important because they are needed in large amounts to produce healthy, high-yielding crops to feed cows. 

“More than 20% of New York’s milk is now assessed for nutrient footprint,” said Quirine Ketterings, professor of nutrient management in agricultural ecosystems in the Department of Animal Science and lead for NMSP. “This emphasizes the importance that farmers place on evaluating their nutrient use and looking for opportunities to improve the sustainability of their farms.”

"Almost all farmers continue to participate after the first year as they see the value in this assessment. Many of them also report being more prepared for making management changes in future years, and appreciate the need for better record keeping because that has advantages beyond the NMB assessment.”

Dairy farmers import and export products to and from their farms to support their day-to-day operations, produce food and make a living. “Nutrient imports” purchased by the farmer may include feed concentrates, forage, fertilizers, purchased animals and bedding. “Nutrient exports” include milk, animals sold or moved from the farm, crops sold and any manure that might leave the farm. 

The NMB is calculated by taking the difference between a farm’s NPK nutrient imports and exports within one calendar year.

Farmers can download a four-page data input sheet that includes questions covering everything from how much fertilizer the farm purchased and what type, to the amount of milk the farm produced and its average protein content.

Farmers can share the completed data sheet with NMSP staff who use the information to create a report that shows how close the farm is to operating as environmentally and economically efficiently as possible. Being within the feasible balance per acre and per hundredweight of milk reduces the risk of nutrient loss and emphasizes how efficiently the farm is converting nutrients into milk. When farms achieve this balance, they are within their “Optimal Operation Zone or Green Box”-- the sweet spot where they are producing milk efficiently with a low environmental impact.

“Some farmers are hesitant to participate in the NMB project at first, because meeting the data requirements can take some effort depending on how farm records are kept,” said Godber. “However, almost all farmers continue to participate after the first year as they see the value in this assessment. Many of them also report being more prepared for making management changes in future years, and appreciate the need for better record keeping because that has advantages beyond the NMB assessment.”

The report that the NMSP team puts together includes an “opportunity table” of key performance indicators (KPIs), identifying potential areas for improvement and helping guide farmers’ future management decisions.

“We always offer to walk through the reports with farmers to help them understand the results and discuss the feasibility of changes in management suggested by the opportunity table for their individual farm,” said Godber. “The opportunity table isn’t intended to criticize current performance, instead it’s meant to open discussions about potential opportunities. 

“The drivers of high balances are often feed and fertilizer imports, which have a price tag attached to them,” she continued. “Identifying potential strategies to reduce these imports could help to improve farm economics and overall efficiency.”

Farmers also receive trend plots that allow them to track progress over time, and see how management changes or weather events may have impacted balances. “The NMB output helps farms make the case that they already implement good practices, opening up more flexibility in terms of distribution of manure across the farms’ cropland,” explained Ketterings. “This could be a significant savings in terms of time and resources for the farm.” 

Demonstrating sound nutrient stewardship by managing N or P within the feasible balances per acre allows farms to make use of benefits offered under the Adaptive Nitrogen Management policy and New York Phosphorus Index assessment, Ketterings pointed out. The NMB considers the whole farm, capturing interactions between different management aspects and allowing farmers to compare themselves to peers, track their own farm progress over time and set achievable goals.

Check out the NMSP website for more information about the whole-farm nutrient mass balance project. If you are a New York farmer who would like to streamline your environmental and economic efficiency by having your milk footprinted for nutrient use, email Olivia Godber.

Madeline Hanscom is a writer for the Nutrient Management Spear Program.

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