Animal manures were the first form of fertilizers used by humankind. People were aware of its benefits to plant life eons ago but, in recent times, it has taken a secondary role to commercially produced granular fertilizers. The main reason for this, of course, was the ease of handling of granular products. There is no odor problem and no livestock is needed to generate it.

Anyway, animal manures may still be useful in the home landscape but not as a fertilizer. Most manures contain only small percentages of nutrients needed by plants. So, there main benefit is that of a soil conditioner. Composted manures will improve both fine textured clay soils and coarse textured sands. They improve the aeration in the soil by encouraging earthworms and beneficial microbes that decay the manure.

There is also evidence that the phosphorus that is in the manure is in a form that is more easily available to plants. In clay soils, phosphorus is bound tightly to the soil particles and may be unavailable. Adding manure to such soils can improve this situation.

Several factors should be considered before using manures in the home landscape:

  1. Availability - Unless you live in or near a rural area where livestock farming is still practiced, it will be very difficult and expensive to obtain.

  2. Weed Seeds - Many weed seeds have evolved to be able to survive passage through an animal's digestive system. This is one of the ways that they get spread about in nature. If the livestock that produced your manure ate roughage that contained weed seeds, they may just be transferred to your garden.

  3. Type of Animal - Rabbit and chicken manure tends to have more nitrogen content in the form of ammonia. This gives off a pungent smell and can harm plants if applied in concentrated form.

  4. Salts Content - Fresh manure which are mixed in with urine will contain a heavy concentration of salts. If these are applied around plant roots in large amounts, the salt will pull the water out of the plant resulting in what is commonly called "burn".

  5. Odor - Fresh manure will have an odor that a farmer may not notice but a typical urban/suburban neighbor will not welcome.

In light of all of these considerations, how can a person use manures in the home landscape? The answer is compost.

Composting manures usually amounts to gathering the fresh matter into a pile and letting it set for a year or so. During that time, the rain and micro-organisms will remove much of the salts. That will take care of much of the odor and plant "burn" problems. It will also be much easier to handle as a dry compost versus very wet fresh manure.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.


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