Adding animal manures can be an excellent way to improve garden soils. Manures can provide many of the micronutrients required for robust plant growth. In addition, adding manure can have significant beneficial effects on the water- and nutrient-holding capacity of the soil. The breakdown of manure in the soil results in a variety of organic gums and resins that bind soil particles together, improving soil structure. Aadding manure can greatly improve living conditions for the wide array of beneficial microorganisms that live in healthy soils.
While the list of benefits of using manure is impressive, take care that manure is right for the use in vegetable gardens. Only apply manures that have been aged for at least six months, as this will eliminate the risk of burning plants with excess ammonia. It is best to use manures that have been properly composted (to a temperature of at least 140 F.), as this will kill any E. coli that may have been present in the raw manure. Proper composting is critical for using manure in food gardens to avoid potential human illness.
Manures from carnivorous animals should never be used. Manure from feed lots contain a high level of salt and should be avoided.