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

Justyna Bohacz

doi:10.1007/s11356-019-04453-2

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.

Highlights

Lignocellulosic waste is often composted or co-composted
The experiments conducted in this study showed that the distribution of organic matter in both compost variants was characterized by different biochemical activity (Fig. 1)
The current study demonstrated that intensive decomposition of the protein fraction of organic matter of both composts in the first 2 months of composting should be linked to microbial biomass synthesis

Summary

Introduction

Lignocellulosic waste is often composted or co-composted. It is mainly produced by mechanical processing of wood and includes branches, sawdust, and bark. According to Sánchez (2009), global annual production of this waste ranges from 0.077 to 380 tons × 106/year. Szwed and Bohacz (2014) reported that over 2.5 million Mg of organic waste from the wood processing industry and 9.0 million Mg of agricultural waste are generated in Poland. Lignocellulosic wastes undergo slow biotransformation and biodegradation due to their hard-to-degrade nature, resulting from the chemical structure (Sánchez 2009). Such wastes are the main precursors of humus along with other microbiological biodegradation products. The quality of the final product of the composting process is conditioned by the activity of different

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Conclusion