Many U.S. dairy farmers have heard about the 2050 environmental stewardship goals for dairy farms and processing plants relating to greenhouse gas (GHG) emissions, water use and nutrient management.
The 2050 goals set by the Innovation Center for U.S. Dairy board last year reflect the improvements farmers have been making for generations as they continue to strive for environmental, social and economic sustainability. The goals are voluntary and support a vision that dairy is an environmental solution.
The 2050 goals include reporting progress every five years, starting in 2025. This reporting commitment is a way to show industry progress in a transparent manner. Reaching the goals will require an all-hands-on-deck approach where existing and future strategic partnerships between farmers and agri-service businesses, public and private research/educational institutions, and public and private funding groups work together. While the individual actions of many dairy farmers and companies have resulted in outstanding progress in reducing dairy’s environmental footprint over time, the industry will need to be strategic and deliberate about developing and implementing technology and innovation to continue to improve.
It is important to think about meeting the 2050 goals as a journey or long-term process and not something that will happen overnight. This effort will also require changes in thinking and improvements in process control that reduce GHG emissions, captures more carbon in the soil and increases nutrient utilization.
The goals and progress reporting schedule have been established, and many important implementation items and knowledge gaps are in the process of being addressed. In the meantime, farmers can consider and evaluate options to lower their GHG and water quality footprints. Often, nutrient management and reducing GHG emissions go hand in hand. Here are 12 practices to consider implementing to lower a farm’s GHG and nutrient footprints. Not every farm can use every practice, but there is something here for any dairy. Some of the items are relatively low-cost, while others require substantial investment.
- Feed the optimum level of protein and phosphorus to reduce the amount of excreted nitrogen (N) and phosphorus (P) and reduce potential nutrient loss from the farm.
- Select diet ingredients that reduce enteric methane intensity (mass of GHG emission per gallon fat- and protein-corrected milk) from cattle by using a nutrition model like the Cornell Net Carbohydrate and Protein System (CNCPS, AMTS, Dalex, NDS) and look for the GHG emissions predictions. (Each program has a different way of reporting.) These tools can establish an enteric emissions baseline, evaluate feed ingredient options and track outcomes for the diets fed.
- Strive to optimize milk production to minimize GHG emission per gallon of milk (intensity).
- Talk to a nutritionist about adding monensin to cattle diets. Monensin can reduce methane (CH4) production by 5% to 7% while improving feed efficiency.
- Optimize the growth of replacement heifers and only raise enough to maintain herd size (assuming no planned internal herd growth). Also, calving heifers as early as possible and reducing the variation around age at first calving can decrease the non-productive period of life, which reduces GHG emissions on a lifetime basis.
- Reduce N2O emissions by capturing more manure N in crops and reducing purchased fertilizer N. This also reduces carbon dioxide emissions due to the energy used to manufacture and transport fertilizer N.
- Improve N management by calculating the appropriate rate of manure for the crop being grown, improve application timing to increase crop uptake and ensure that maximum application rates do not exceed N needs. Overapplication of N increases N2O losses per ton or bushel of feed produced and can also impact water quality.
- To capture and conserve soil carbon and save fuel, adopt strip till or no-till practices in your crop production system.
- Plant cover crops after corn silage to make use of leftover nutrients and leave as much crop residue as possible to add carbon to soil.
- Combine manure injection and no-till practices by using low-disturbance shanks to inject manure to conserve carbon, reduce soil loss, reduce fuel-based CO2 emissions and keep N and P on the land and out of runoff.
- Reduce manure storage CH4 emissions by installing an anaerobic digester and ensuring the biogas is captured and used to produce renewable electricity (RE) or renewable natural gas (RNG).
- Reduce manure storage CH4 emissions by installing a gas-tight impermeable cover to capture biogas. In moderate and cold climates, ensure the biogas is collected and flared. While in hot climates, use the biogas to produce RE or RNG. Covering a manure storage also reduces fuel costs and associated GHG emissions in humid regions because less rainfall mixing with manure results in less material transported and applied to fields.
As a farm embarks on any of these practices, it is important to keep track of what is implemented so any change can be credited to your business as the industry moves toward the stewardship goals.
Mike Van Amburgh is a professor with the department of animal science, Cornell University. Curt Gooch is a dairy environmental system solutions engineer, Dairy Management Inc.
Greenhouse gases
The GHG gases of concern for dairy farms are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Carbon dioxide is emitted from fossil fuel engines used on-farm (mainly cropping, feed handling and manure handling) and off-farm (trucking) and during commercial fertilizer manufacturing.
Methane, the largest source of GHG associated with the dairy value chain, is emitted from cows and long-term manure storages as the result of biological breakdown of organic matter. Nitrous oxide can be emitted from barns, drylots, manure storage, pastures and cropland under certain conditions.
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