Horse manure, along with chicken manure, is a common garden fertiliser. It has a high nutrient content and can enrich any soil. Horse manure is an example of organic fertiliser, making it an acceptable form of plant food for gardeners who want to avoid chemical amendments. To use horse manure without harming the fruit tree, you must properly age it or purchase composted manure. When applied to the soil surface, horse manure acts as a slow-release fertiliser.
Pile the fresh horse manure into a compost bin and turn it once a week with a pitchfork. Turning it will release heat and visible steam, and will ensure even distribution of beneficial microbes throughout the manure.
Leave the manure in the compost bin for one year, turning it regularly. You can add kitchen scraps or other organic manures, if desired. If you do not age the compost for the proper amount of time, it will heat up around your fruit tree and may harm it.
Spread the composted horse manure around the base of your fruit tree in a 2- to 3-inch layer. Do not let the compost touch the base of the tree. The layer of compost should reach out to the tree's drip line, which is the widest point of the foliage. Spread the manure in the early spring. The compost will slowly feed the tree, so other fertiliser applications throughout the year will not be necessary.
Replenish the layer of manure the next spring.
Compost applied in this manner doubles as a mulch, so a separate mulch application is not necessary.