Manure can be used as an organic material to improving soils when used as a mulch or soil amendment.
Apply fresh manure only in the fall so it has the winter to decompose. Applied in spring or summer could potentially transmit pathogens such as E-coli.
Manures can also be high in salt which is harmful when added to the soil. Salts build up in the root zones of plants in heavy clay soils with poor drainage causing seed-germination failure, stunted plants, or leaf burn.
When adding manure or compost made with manure, add no more than one inch per year and cultivate it into the soil six to eight inches deep. By improving drainage with organic matter, salts will be leached through the soil.
Other options for improving soil are to add compost, leaves, chopped straw and other low-salt organic materials instead of manure.
For more information, see the following Colorado State University Extension fact sheet(s).
- Choosing a Soil Amendment
- Managing Saline Soils
- Organic Fertilizers
- Using Manure in the Home Garden
- Vegetable garden: Soil Management and Fertilization