Chemical characteristics of Malian and Belgian solid waste composts

Two composts, a Malian (C-1) and a Belgian (C-2), and a peat substrate (C-3 ) were analyzed for their suitability for land application. The results rev ealed that the materials can be used in agriculture but only the composts c an supply all macro-nutrients necessary for plant growth. The fractionation of Mn, Fe, Zn and Cu in operationally defined fractions (water soluble, ex changeable, complexed, organically bound and residual) allows estimation of the availability of metals for uptake. For example, 16% of the total Mn in the composts (C-1 and C-2) and 22% in the peat substrate would be plant av ailable. Available Fe in the three materials was less than 2%. Available Zn varied from 10% to 25%. The fractionation also allowed estimation of the p otential for contamination of groundwater following the applications of com posts to agricultural lands. (C) 2001 Elsevier Science Ltd. All rights rese rved.