Compost: a valuable resource to renew our soils
Compost supplies significant quantities of organic matter that can build healthy soils for the long-term. It also has the unique ability to improve the quality of soils structurally, nutritionally and biologically. This range of benefits supports better outcomes in agriculture and landscaping applications.
● Soil structure, porosity, and density improve, which creates a better plant root environment.
● The addition of organic matter as compost increases infiltration and permeability of heavy soils, which in turn, reduces erosion and runoff.
● Water holding capacity improves, which is especially helpful in reducing water loss in sandy soils. The Natural Resources Conservation Service states that every 1% increase in soil organic matter can result in up to 20,000 gallons of available water per acre!
● Compost delivers micro and macronutrients to soil through a slow release. Applications of compost can have a positive cumulative effect on nutrient availability.
● An increased population of certain microorganisms may control or suppress certain soil-borne plant pathogens such as pythium and fusarium, which cause root rot, as well as nematodes.
● The cation exchange capacity of soils and growing media increases with the addition of compost. Cations are groups of nutrients. The total negative charge in soil determines the total number of cations it can hold. A higher exchange capacity means that the soil has a greater ability to both hold and cycle (or exchange) nutrients.
● Compost supplies microorganisms to soils, which play an important role in organic matter decomposition that then leads to humus formation. Humus contains nitrogen and other elements in a highly usable form for plants; it also contributes to a loose structure and texture of the soil that allows plants to access oxygen.
● Compost improves soil’s capacity to stabilize pH at 6.5 - a slightly acidic level - which allows for optimal plant nutrient uptake. Keep in mind that certain crops thrive in more alkaline or acidic conditions.
● The ability of compost to bind heavy metals and other contaminants is useful as filter media for stormwater treatment. In addition, the microbes in compost are able to degrade some toxic compounds including petroleum, which is useful in soil remediation.
*The information cited above is adapted from United States Composting Council factsheets and research.