welldecomposed

Welldecomposed is a term used in soil science and horticulture to describe organic matter that has reached a mature, stable state through the decomposition process. In practice, welldecomposed material functions as humus-like organic matter that contributes to soil fertility, structure, and moisture retention. The term is most commonly applied to compost and leaf mold that has aged under controlled conditions.

Characteristics include a dark to black color, a fine to crumbly texture, and an earthy odor. It contains relatively few readily decomposable compounds and a higher proportion of stable humic substances. Welldecomposed material should exhibit a low volatile content and minimal heat generation, indicating microbial activity has slowed to a stable level.

Production and indicators: achieved by proper aeration, moisture control, and time. Typical turning and temperature management over weeks to months promote complete breakdown. Maturity is indicated by stability tests (for example, constant temperature, absence of heat, neutral odor), absence of phytotoxic compounds, and ease of mixing into mineral soils.

Common sources include mature compost from mixed green waste and manure-based compost, and leaf mold that has aged. It is contrasted with partially decomposed materials at early stages, which may be acidic, odorous, or clump together.

Uses and benefits: improves soil structure, increases water-holding capacity, enhances nutrient availability and microbial activity, and reduces erosion. It can also support plant growth by supplying nutrients gradually and aiding root development. Limitations: not all welldecomposed materials have the same nutrient content; testing is recommended for precise fertilizer planning. Overapplication can lead to nutrient imbalances or salinity.

See also: composting, humus, soil organic matter.