The effect of desert annual plant decomposition on soil microbial community

Desert ecosystems are characterized by harsh abiotic conditions with low annual rainfall, unpredictable in time, frequency, and dispersion. In such a system, the soil microflora should fulfill its biological and functional role by decomposing plant organic matter. This study evaluated the effect of annual-plant decomposition on soil microbial community composition and functional diversity. We assumed that the microbial functional diversity values would be related to the amount of lignin litter content. We collected soil samples and plant litter of two annual plants, Avena wiestii and Reboudia pinnata, common in the Negev mountain area, Israel, during four seasons. Genetic characterization of the soil microbial community was carried out. Our results indicate that the presence of plant litter in the soil causes many changes in the size, composition, and diversity of a soil microbial community. Functional diversity values were affected by adjacency to litter in the four seasons. Soil and litter moisture and organic matter were affected by season and plant type. Soil and litter microbial biomass and respiration decreased as the decomposition process progressed. There was a decrease in the utilization of all four carbon groups when measuring the catabolic profile of the microbial community.