A tractor and a manure spreader are needed to ensure proper field application of stored manure. Some small farms may be able to utilize small ground-drive spreaders that can be pulled behind an all-terrain vehicle or pickup instead of a tractor. Pull-type spreaders are traditionally used, although truck-mounted spreaders are sometimes used on larger farms.
Solid manure can be removed from storage using front-end loaders, scrapers, or other handling equipment. Small or limited-resource farms can get by with equipment as simple as a wheelbarrow and pitch fork. The size of the equipment influences the time required to load, haul, and spread manure. For more information see Nutrient Planning on Small Farms.
Manure should not be spread where and when there is any risk for water pollution, such as near streams, ponds, wells or other waterbodies. Your local soil and water conservation district or Natural Resources Conservation Service office can also help identify if additional special protection areas exist on farmland and bordering properties.
Stored manure should be applied to the soil in a thin layer to speed drying and discourage fly breeding. Spreading incompletely composted manure on horse pastures should be avoided due to the risk of infecting pastures with internal parasites. Manure should be spread at agronomic rates (rates equal to or less than plants will use in a year). When stockpiled manure is spread on crop fields, the application may not meet the total needs of the crop. Each source of horse manure will vary, especially when different bedding sources are used. Typically, a ton of horse manure will contain eleven pounds of nitrogen, two pounds of phosphorous, and eight pounds of potassium. Average values are given in the table below and can help to determine the number of acres needed to properly apply the horse manure. Refer to your local Cooperative Extension office to get a list of laboratories that will do manure analysis.
|Manure||Percent Solids||Nitrogen - N||Phosphorus - P2O5||Potassium - K2O|
Spring is the preferred time to apply manure. Forage or hay crops generally provide the greatest flexibility in planning land application operations. Cool season grasses can generally utilize manure nutrients from early spring to late fall, and application equipment generally does not adversely affect the crop regardless of its growth stage. However, spreading manure on wet soils should be discouraged as it leads to soil compaction and tearing of the top soil.
When spread, not all nutrients in manure are immediately available for plant use. The amount of nitrogen available is a function of the percentage of nitrogen in the manure, whether or not it is incorporated in the soil, and the rate of organic matter decomposition of the manure. Nitrogen availability (during the first growing season) will range from 35% of the total nitrogen when manure is spread on the soil surface to 60% when immediately incorporated into the soil. Availabilities of phosphorus from phosphate (P2O5) and potassium from potash (K2O) are commonly set at 80% and 90% of totals, respectively. For links to publications that include more detailed information and formulas for estimating nutrient availability from manure see Manure Nutrient Management Educational and Informational Resources.
Horse manure often has an additional consideration when it comes to nutrient availability. Sawdust or wood shavings are high-carbon materials that require a great deal of nitrogen to break down. This process can tie up available nitrogen, rendering it unavailable to plants or crops. A fact sheet on how to manage horse manure that contains wood shavings or sawdust is Horse Manure Management: The Nitrogen Enhancement System.
In situations where land application is not an option or the farm has more manure than can be appropriately utilized, the producer will need to consider Off-Farm Manure Disposal options.
Author: Michael Westendorf, Department of Animal Sciences, Rutgers, The State University of New Jersey