Soil drying and rewetting represents a common physiological stress for the microbial communities residing in surface soils. A drying–rewetting cycle may induce lysis in a significant proportion of the microbial biomass and, for a number of reasons, may directly or indirectly influence microbial community composition. Few studies have explicitly examined the role of drying–rewetting frequency in shaping soil microbial community structure.

Plant litter decomposition is not a purely chemical or physical process, it is basically a biological one resulting from the diverse activities of microorganisms, protozoa and various other soil organisms like insects and worms. The bacteria and fungi play a very significant role in plant litter decomposition and humus formation. The fungi which colonized decaying substrates could use only simple substrates such as sugars and they referred as sugar fungi. Garrett suggested that the root infecting fungi open the way for a sequence of saprophytic sugar fungi, cellulose decomposers and finally lignin decomposers. The initial rates of losses of differrent components could be ranked as sugar > hemicelluloses> cellulose> lignin. During this succession, the substrates were found to become progressively depleted. This biochemically based succession was believed to be reflected in a taxonomic way as the Phycomycetes to be considered as sugar fungi, the Ascomycetes and Deuteromycetes as cellulolytic and finally Basidiomycetes as lignin decomposers.

Composting of pruning waste, leaves and grass clippings was monitored by different parameters. A windrow composting pile, having the dimensions 2.5 m (height) x 30 m (length) was establish. The maturation of pruning waste compost was accompanied by a decline in NH4+-N concentration, water soluble C (WSC) and an increase in NO3–-N content. Both organic matter (OM) content and total N (TN) losses during composting followed a first-order kinetic equation. These results were in agreement with the microbiological activity measured either by the CO2 respiration or dehydrogenase (DH-ase) activity during the process. Statistically significant correlations were found between DH-ase activity, easily biodegradable organic C forms, NH4+-N and NO3–-N concentrations and organic matter content and N losses. For this reason, DH-ase activity and the CO2 evolution could be used as good indicators of pruning waste compost maturity. In contrast, humification parameters data from the organic matter fractionation did not agree with the initially expected values and did not contribute to the assessment of compost maturity. Neither the cation exchange capacity nor the germination index showed a clear tendency during the composting time, suggesting that these parameters are not suitable for evaluating the dynamics of the process.