Glomalin-Related Soil Protein Content in Areas of Degraded and Revegetated Caatinga in the Municipality of Irauçuba

Anthropic activities, combined with the natural ones, may trigger soil degradation, which has increased day by day and contributed to accentuating the desertification processes, resulting in losses of biodiversity and fertility of the soils. Because of that, the utilization of tools that indicate the stages of such degradation and recovery becomes necessary, in order to make viable and adequate management of these areas. Thus, the study on arbuscular mycorrhizal fungi (AMF), as a perspective to facilitate the recovery of degraded areas has increased, especially for the production of glomalin-related soil protein, which is of great importance for aggregate stability, besides showing a great potential of utilization as soil quality indicator. Therefore, the present study aimed to evaluate the contents of glomalin-related soil protein, correlating with chemical, physical and biological attributes in areas of the municipality of Irauçuba-CE- area degraded by overgrazing, area under process of natural revegetation managed with the exclusion of domestic animals and area of native forest, characterized by tree-shrub Caatinga vegetation. Disturbed soil samples were collected in the layer of 0-10 cm in each area and evaluated for AMF attributes, soil chemical attributes and physical attributes. The results obtained with the tests of means prove that, among the three areas, only the native forest showed significant differences with respect to both fractions of the protein. However, in regard to spore density and aggregate stability, the areas of native forest and exclusion showed the best mean values. The content glomalin-related soil protein (GRPS), associated with other edaphic attributes, contributes to discriminating the quality and to the monitoring of areas with different levels of soil degradation. The highest correlation values were observed among the contents of calcium, nitrogen and organic carbon and both GRSP fractions (easily extractable- GRSPEE,which represents the recently deposited frsction that has not yet suffered biochemical alterations in the soil; total- GRSPT, which is strongly adhered to the clays), indicating that the protein directly influences the contents of these elements in the soil.