Arbuscular mycorrhiza, carbon content and soil aggregation in Sonoran Desert plants

Desert trees and shrubs play a relevant role in stabilizing the deserts ecosystems, and mycorrhizal association is very important for its adaptation and survival in arid and semi-arid areas. The influence of mycorrhizic fungi on the formation of water stable aggregates through glomalin and on soil carbon content has been studied. We sampled the rhizosphere of representative trees (Olneya tesota, Prosopis juliflora, and Parkinsonia microphylla), and shrubs (Jatropha cuneata and Larrea tridentata) of the Sonoran Desert for four seasons in order to evaluate the mycorrhizal status, carbon and glomalin accumulation, and their relationship with water stable aggregates. Results showed that mycorrhizic association is present all the year on studied plants, with values from 1.2 to 57% of mycorrhizal colonization, with variations depending on the season. The accumulation of carbon in the soil profile has significant differences between plants and ranged from 1.1 to 1.75% for Larrea and Prosopis, respectively. The water stable aggregates were significantly different between plants and ranged between 24% and 42%. Glomalin correlation with carbon content and water stable aggregates shows the role of mycorrhizal fungi on soil quality, highlighting influence on carbon content in rhizosphere.