ABSTRACT
Composts, some wood products, and mulches discussed in this chapter decompose into humus and impart to the soil all the beneficial qualities derived from traditional organic matter additions to the soil whether from crop residues, leaf litter, or intentional soil amending procedures. Wood products such as preservative-treated lumber have been disposed on land or used in building and while not considered soil amendments have caused concern about contamination of the soil. Living mulches impart some of the same benefits as surface-applied organic mulches, such as increased soil carbon, increased rain infiltration, and reduced soil erosion. Several methods of assessing compost maturity have been reviewed, with the authors suggesting that no method is adequate to assess the maturity of composts from all the different types of substrates. The potential for high salinity in mixes has limited the use of some composts as soil amendments for potted crops.
