Compost your manure for small fields that do not require the use of a manure spreader. Areas that are an acre or less can be covered with manure, blended with grass clippings or leaves, which is much easier to spread, has a less pungent smell, and contains less pathogens such as e-Coli that can contaminate the local water table. After composting your manure, spread it on the field from either the back of a pickup or with buckets. Composted manure does not require calculations for either run-off or nitrogen content, as it is balanced with organic materials.
Pick your crops. You need to know what you are going to grow on the land to determine the amount of fertilizer you need to disperse. The type of crop determines the amount of nitrogen to be absorbed before the manure reaches the local waterways. Manure rich in nitrogen that reaches the watershed causes severe environmental problems by over-fertilizing the water and causing an overgrowth of aquatic plants that, in turn, depletes the oxygen in the water during decomposition.
Determine how much nitrogen content is in your particular batch of fertilizer by taking it to a lab. To find a lab near you, call your county extension office for recommendation. They might do the testing themselves as a part of their community services. Ask specifically for the nitrogen results when your item is tested.
Research the amount of nitrogen your particular crop needs per acre. For example; the nitrogen needed for sweet corn is 100 pounds per acre. With the results from your lab work, determine the amount of manure you need to add the required amount of nitrogen per acre. You can download a worksheet to help you determine this amount, or ask your county extension officer for help.
Rent or purchase a manure spreader for the job. There are three kinds: rear, side, and specialty spreaders. Rear delivery works best with dry materials, and side delivery can handle both wet and dry manure. Specialty spreaders refer to the coverage each pass makes; they are usually designed for farmers who need a certain row width covered.
Load your manure according to the manufacturer's directions. Spray your field with the recommended concentration, as stated by your worksheet or recommended by your county extension officer.