Contributed by Mitiku Mamo, UNL Extension Educator, Crops and Water
Due to Covid-19 Pandemic, there is a concern that Dairy Farmers may not be able to ship milk to processors. Consequently, in the event they find themselves in this situation, some local farmers have been making inquiries on agronomic rate of land applying milk as a fertilizer. Milk is an organic and the same principals used to manage manure can be used to manage milk when land applying it.
Land application of milk, at least in some states, is regulated in the same manner as land application of process wastewater. One immediate option is to store milk in an existing manure storage structure. This would be preferable to applying ahead of rain that generate surface runoff or leaching into groundwater. Nebraska Department of Environment and Energy, in a Memorandum published/issued on April 3, 2020 provides guidance on disposal of milk and milk products in Livestock Waste Control Facilities (LWCF). For the guidance please go to http://deq.ne.gov/NDEQProg.nsf/onWeb/COVID and click on Milk Exception Guidance.pdf under COVID-19 Information. The guidance allows for an agronomic rate and suggests incorporation to avoid odor and other issues.
Milk contains around 45 lbs of nitrogen, 18 lbs of phosphorus (P2O5), and 15 (K2O) lbs of potassium per 1000 gallons of (Kulesza, 2020). For perspective, it requires 3,000 gallons of milk per acre to provide about 135 lbs of nitrogen, 54 lbs of phosphorus, and 45 lbs of potassium. Putting milk on fields going to corn instead of soybeans will allow better use of the nutrients. To determine the appropriate application rate of milk, it is essential that a realistic yield, based on the average of the past several years of yield data be used for the field selected to have milk applications. There are several UNL tools online to help determine the economic N rate and appropriate nutrient management. Under no conditions should the total N applied as milk be greater than the crop needs for that year.
Because of all the nitrogen and phosphorous in milk, it can be considered as immediately plant available. Consider applying only a portion of the crop’s needs with milk and applying the balance through alternative methods.
Milk produces a very strong odor while it is decomposing, so in the spirit being a good neighbor try to apply it to fields farthest away from the neighbors. Injecting or incorporating land applied milk, in addition to reducing the risk of surface runoff will also minimize odor. If the field needs lime or other nutrients that would benefit from incorporation, these could be applied before tillage.
It is unfortunate that milk must be ‘wasted’ after all the effort and money was spent to produce it. However, when managed correctly it can substitute for fertilizer, and be applied in a manner that is not a threat to our neighbors or the environment.