Composts from organic waste materials as substitutes for the usual horticultural substrates

Abstract

In recent years, composts of different organic waste materials are more and more being used as primary materials to prepare potting substrates. The materials normally used in substrates are, on the one hand, pine litter and peat as organic raw materials, and on the other hand perlite, rockwool, expanded clay and vermiculite as inorganic materials. In recent years, considerable research has been carried out on the use of other organic materials such as bark, manure, urban compost, sludge, etc., in horticultural substrates. In most cases, these organic materials cannot be used as such because of disadvantages such as phytotoxicity, nitrogen immobilization, high salt content or structural incompatibility. Composting permits the decrease of many of these disadvantages. Composted end-products, properly mixed, can make excellent horticultural substrates. Thus, adequate potting substrates have been prepared from composted bark, town refuse and sludge from water-purification plants.