Analyses of soils sampled on Madagascar Highlands following temperature and rainfall gradients in 2014

Each mechanism gets its own dynamics, involves its own microbial actors and targets different soil organic matter (SOM) pools. The present study aims to evaluate how climatic parameters drive the intensity of each PE generation mechanism via the modification of microbial and physicochemical soil properties.

Soils were sampled (May 2014) in the center of Madagascar, along climatic gradients designed to distinguish temperature from rainfall effects. Abiotic soil descriptors were Bulk Density, granulometry (clay silt and sand %), soil humidity, pH, CEC, oxydable Aluminium and Iron (estimation from spectral data) Kaolinite and Gibbsite content (estimations from spectral data), Total C, N and P, mineral N (addition of NH3 and NH4 data), available P. Biotic descriptors were microbial biomass phosphorus (MBP), molecular microbial biomass (MMB), 16S and 18S copy numbers per g of soil (qPCR), and bacterial and fungal communities composition (at the phylum level) obtained by 454 pyrosequencing methodology.