Changes in mineral forms of nitrogen and sulfur and enzymatic activities during composting of lignocellulosic waste and chicken feathers

Abstract

The aim of this study was to show the dynamics of changes in the activity of enzymes responsible for C, N, and S metabolism, i.e., cellulase, protease, urease, and arylsulfatase in two lignocellulosic composts as well as changes in the concentration of mineral forms important in plant nutrition (N-NH₄⁺, N-NO₃⁻, S-SO₄²⁻). Most of the enzyme activity was higher during 10 weeks of composting in compost I, containing higher amounts of easily available organic matter than in compost II. Enzymatic activities in compost II remained at a higher level for a longer time, but they increased at a slower rate. Mineral content changes in the compost mass consisted primarily of an increase in N-NO₃⁻ concentration and a decrease in N-NH₄⁺ and S-SO₄²⁻ levels, especially in compost I. The concentration of mineral nitrogen and sulfur forms in compost water extracts was about 10–100 times lower than in the compost mass. At the end of composting, the amount of sulfates in the compost mass was 30 and 150 mg kg⁻¹ dw in compost II and I, respectively. In this context, the composts obtained should be considered valuable for fertilizing soils poor in this component and for cultivating plants with high sulfate S demand.

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