Approaching compost stability from Klason lignin modified method: Chemical stability degree for OM and N quality assessment

Compost stability and maturity can be assessed by many methods, differing in both sample preparation and produced information. The method proposed here is the chemical stability degree (SD) the origin of which can be related to the Klason method for lignin determination in wood and pulp. It allows determination of the stability of organic matter and nitrogen through resistant organic matter and non hydrolysable nitrogen determinations, in any kind of dry and ground sample. This method avoids the disadvantages related to the determinations conducted on wet sample, such as respirometries or self heating test, which are effected by the water content and the particle size. The SD has been applied to different raw organic materials as well as to composts of different origin, producing reliable results. The Pearson correlations of SD with other usual parameters that can inform on compost quality have been of interest, revealing its usefulness to determine compost stability.