Manure: Is it a waste product or a valuable asset?
The answer to this question may get you varied responses depending on who you ask. Some non-farm neighbors may detest it solely because of the smell. Others may blame any water impairment on livestock manure, justified or not. Some may view manure as an opportunity for capturing methane as a “green” energy source through anaerobic digestion. Still others wish to burn the whole product for energy production. Of course, there is the standard option of using manure as fertilizer. All sources of livestock manure contain an excellent source of nitrogen, phosphorus, and potassium (N,P,K), organic matter, and several micronutrients. Many parts of the USA and the world do not have the luxury of abundant cropland in close proximity to livestock production as the Midwest USA. In the Midwest, millions of cropland acres need what manure has to offer.
I have spent considerable time discussing phosphorus balance. So what is an out of balance phosphorus farm? A farm system is out of phosphorus balance when imports of phosphorus exceed exports. If a farm system remains out of balance for a few years, the usual result is increased soil phosphorus levels. The challenge is it usually takes more acres for a livestock farm to achieve phosphorus balance than the number of acres needed to utilize all the nitrogen in manure for corn production. Why is it important that high phosphorus soil tests increase the risk of losing phosphorus from either soil erosion or surface water runoff from snowmelt or a rain event? The risk is that any phosphorus that enters surface waters can produce blue/green algae blooms and may contribute to the hypoxic, or dead, zone in the Gulf of Mexico.
A result of the phosphorus balance project is a series of case studies based on actual livestock farms. Each case study highlights a different management option a livestock farmer might use to help mitigate an out of balance phosphorus situation. The University of Minnesota Extension Manure website has these case studies posted. There you will find case studies, built on real farm situations, with a what-if scenario illustrating what would happen to their phosphorus balance if they would perform any one of the management options.
Some of the topics illustrated in the case studies are: Increasing land base, increasing crop production on existing acres, reducing/eliminating corn starter containing phosphorus, lowering phosphorus content in the ration, reducing feed shrink, incorporating manure to decrease nitrogen losses permitting lower application rates, exporting manure, and stopping/reducing importing of manure. Not all of these practices are an option for every producer, but most farmers have one or two options. Increasing land base is an obvious but often difficult option for many reasons. Previous articles addressed some of these practices in greater length - for reference check the UMN Extension Dairy website under the manure section.
So what about our crop farming neighbors who could use some manure on their land? Is it worth it to them to purchase manure from their livestock neighbors? Usually it is, especially if their fields need all three major nutrients: nitrogen, phosphorus and potassium. How much should they pay? That depends on the manure analysis, the soil tests of the fields receiving the manure, and the crop planted. With current economics, liquid dairy manure could be worth up to $200 per acre to the farmer purchasing the manure if the dairy farmer performs and pays for the application. For a closer estimate, check out the UMN Extension manure value worksheet.
One of the latest discussions in agriculture is "soil health". This topic encompasses many practices including minimum tillage, crop diversity, and cover crops; one element always present is livestock manure, pasturing livestock is frequently the discussed practice. Nevertheless, the crucial component is reaping the benefits of livestock manure by increasing the organic matter and soil structure. This should be of no surprise to many livestock producers who have acquired new ground that has been manure deprived for many years. They "wake up the ground" by incorporating manure into the soil, usually increasing crop yields.
Livestock producers have a phenomenal resource - manure. All too frequently, non-livestock farmers do not want to bother with the "inconvenience" of manure; compared to commercial fertilizer it is cumbersome, expensive to handle, can cause planting delays, and does not perfectly match the crop's nutrient needs. So is manure a waste product or a resource? If mismanaged, manure can cause social and environmental issues, but when properly managed, manure is a tremendous resource that provides many benefits for livestock producers and anyone land applying manure.