Caractérisation des Phases du Processus de Compostage Par Une Approche Multidimensionnelle: Application Au Cycle de L'Azote Characterization of the Composting Stages by a Multivariate Analysis: Application to the Nitrogen Cycle

Microbial composting stages were characterized by a multivariate analysis, a global approach instead of a classical univariate analysis of correlations, as part of a study of the organic nitrogen reorganization during a cow manure composting process. Two adiabatic composters were sampled at thirteen intervals during composting and nineteen physical, chemical and biological descriptors were retained for numerical analysis. A principal component analysis (PCA) brought out the most probable factors governing sample distribution. The first three axes of the PCA represented 71% of the total cumulated variance. Sample distribution was along three gradients: organic matter degradation, slow hydrolysable nitrogen, microbial activity. A cluster analysis by average linkage for each composter created five groups of days which are approximately the same size. The interpretation of these groups in terms of the evolution of the microbial composting stages utilized the superposition of clusters onto the first three axes...