Effects of incorporation of vermiculite on carbon and nitrogen retention and concentration of other nutrients during composting of cattle manure

Abstract

A study was carried out to determine the effects of vermiculite inclusion into cattle manure on compost performance and nutrient retention during composting. All compost mixtures passed through the major composting phases and inclusion of vermiculite increased retention of total nitrogen with treatments recording N losses of 27.8, 25.3, 21 and 14.5% for the 0, 10, 20 and 30% vermiculite treatments. Vermiculite inclusion also reduced mineral N (as a percentage of initial nitrogen), NH4+:NO3− ratio and C:N ratio and enhanced the Ca and Mg concentrations of the final cattle manure composts but lowered K concentration. Incorporation of vermiculite in composting of cattle manure reduced the Ca: Mg ratio of final compost to <1. Further work is recommended to determine the availability of nutrients, particularly N, K, Ca and Mg when these co-composts are applied as organic fertilisers.