Evaluation of the methanogenous potential of various rations and of the digestate effects (dry and liquid fractions) on some biological functioning indicators of the soil in relation with fertility

Methane producing potential assessing of 16 rations (manure/liquid manure) comes from 16 farms shows that, many of them have a good quality to product enough biogas (under ideal conditions) to limit their energy dependencies. Application (according to the recommendations) of ration, raw digestate or undergoing phase separation (solid and liquid fraction) had no effects on micro-organisms (biomass C, N bacterial and fungal molecular biomass) and indicators of soil fertility (carbon mineralization and enzyme activities). Several factors can explain these results. Ration and digestate characterization show a organic matter proportion, carbon/nitrogen ratio and nitrogen contents lower than the typical values of such values matrix. Soil's characterization indicate high pH (8,2) and active limestone important proportions. Finally soil conditions during its removal and storage time a bit longer could have biased the results. (author)