Effect of soil microorganisms on organic carbon sequestrationindifferent soil landscapes of the Ouargla’s basin

The objective of this work is to study the effect of microorganisms on carbon sequestration in
different soil landscapes of Ouargla’s basin. Ouargla is part of the arid zones of the Algerian
Sahara, which is characterized by high temperatures, low and irregular precipitation, sparse
vegetation and soils poor in organic matter. However, the soil remains a favorable environment
for macros and microorganisms which tolerates this deficit. The soil provides ecosystem services
to these environments by protecting natural resources. Microbial biomass, which represents on
average 2 to 4% of organic carbon, is involved in renewing organic matter in the soil. For this
study, 7 stations of different pedo- sequences were chosen. After collection, the samples
underwent microbiological analyzes for enumeration of bacteria and fungi, fumigation-extraction
and physicochemical analyzes. The enumeration of the main microbial groups in bacteria and
fungi showed the predominance of bacterial microflora, followed by fungal microflora at higher
values in cultivated soil and those of Sebkhat. The identification of fungal species according to the
determination keys allowed us to identify the following species: Alternaria alternata, Rizopus sp
and Aspergillus niger, as well as yeasts. The microbial carbon values show that this parameter is
higher in Sebkhat N’Goussa, gypsum soil in Frane and in cultivated soil. These are the stations
where high values of organic carbon and organic matter are recorded. We can say that
microorganisms play an important role in carbon sequestration. They mineralize microbial
residues and provide carbon to the stable organic matter fraction of the soil. 

 

Key words: carbon sequestration, ecosystem service, microbial carbon, organic carbon, Ouargla.