Biological, Chemical and Physical Properties of Composted Yard Trimmings as Indicators of Maturity and Plant Disease Suppression

Abstract
A full scale system for composting of fermented, odiferous yardwaste trimmings was developed that produced a stabilized compost, minimized odor generation and prevented leachate formation. Characteristics of the compost highly significantly correlated with composting time included availability of the plant nutrients K, P, Ca and Mg, electrical conductivity, total carbon to nitrogen ratio, cation exchange capacity, stability based on O2 respirometry, and finally, nitrate-nitrogen concentration. Radish was a good indicator of compost maturity. As the compost matured, suppressiveness to Pythium damping-off increased but it remained conducive to Rhizoctonia damping-off.