Got manure? Do you wish you had more manure? Do you have too much manure? Got a plan for your manure? Is spreading manure a necessary chore, or is it an opportunity to enhance your bottom line?
Are we spreading our manure based on nitrogen or phosphorus needs of our crops? Which method is correct? That partially depends on your fields' phosphorus soil test. Soil test of 21 ppm Bray 1-P or 16 ppm Olson is what is recommended for conventional crop production in Minnesota. Applying manure is an excellent method of supplying NPK and other soil nutrient needs. On a number of livestock farms, after many years of applying manure to fields based on nitrogen needs, the soil phosphorus can be substantially higher than the recommended 21 ppm Bray 1-P or 16 ppm Olson.
Why does this matter if phosphorus is fairly stable in the soil? It matters because of eutrophication - the process of excess phosphorus entering a water system producing excess growth of green algae and other undesirable plants, and eventually causing the death of desirable aquatic life. When field soil phosphorus levels are quite high, any soil erosion contains considerable more phosphorus than normal. If this is your situation, there are various options available to help capture more of your manure's value and simultaneously protect the environment. Let us discuss some land and manure management options available.
- Acquire more land. This is not always easy; first you must be in a financial position to handle payments if considering purchasing. Then there must be land available for sale or lease within a reasonable distance from your livestock site. What is a "reasonable distance"? That depends on your equipment, manpower, and traveling tolerance. You must also have adequate equipment and labor force to handle the extra acres. If additional land is a need on your farm, a long term goal may be financially positioning yourself, enabling acquisition of land that enters the market in the future within "reasonable distance".
- Sell manure. This is frequently a tough one for producers to swallow. Most livestock producers are aware that manure is a valuable resource and want to capture this value on the land they are managing. It is also frequently difficult to obtain the full value of manure from neighbors. This can be because the neighbor does not believe the claimed value of manure is accurate, they do not want to be inconvenienced by the timing of manure application, or they know you have to move the manure and just low-ball you on the price. For any of these reasons, your knowledge of the value of manure can be improved by using the 'value of manure' spreadsheets on the University of Minnesota website: http://z.umn.edu/valueofmanure.
- Move manure to distant fields, either your own field or someone else's. This is usually difficult and involves additional cost. If you are able to handle this issue, you may have more flexibility with the discussion above about acquiring additional land. Installation of a liquid-solids separator may allow for easier and more economical transportation of the solids portion of manure over a longer distance. However, if your close-in field acreage is low you may end up moving some of the liquid portion the longer distance anyway. Manure analysis results have shown that NPK ends up in both the solids and liquid portions of separated manure. Manure testing is recommended here as with all situations.
- Employ grid soil sampling in your fields to discover areas that need the additional nutrients from manure. Many times there are areas of fields that have nutrient needs that are discovered in grid sampling that go undetected in a composite soil test. Locating these areas may allow for higher manure application in areas than a composite soil test would allow. This may also help maximize the yield potential of the entire field.
- Enhancing crop yields. Most practices that increase yield on your existing land base would require less purchases of forage or grain for the same amount of livestock. This can decrease the importation of phosphorus into your farm system.
Some livestock producers have sufficient acres, allowing these producers to pinpoint the areas or fields with the greatest need of the NPK and other manure nutrients. This allows them to extract maximum value from their manure without over applying nutrients on the fields. Livestock producers in this situation consistently have crops to market in addition to the use of forages and grains for their livestock.
This winter there will be a series of workshops around the state illustrating various strategies for balancing phosphorus imports and exports on livestock farms. Contact your local University of Minnesota Extension Educator later this fall for the time and location of the workshop nearest you.