The response of glomalin-related soil proteins to fire or tillage

Both TOC and GRSP were significantly lower in the cultivated soil than in the unburned forest. Fire did not change the content of TOC, although GRSP increased with increasing fire severity. The relative amount of small aggregates was higher in the burned and cultivated soils, likely because of the breakdown of macroaggregates by heating and tillage, respectively. TOC, EEG, and RG generally increased in concentration with decreasing aggregate size. The linear regression analysis revealed significant relations between GRSP and TOC in all studied treatments; however, the GRSP/TOC ratio was significantly higher in the soil burned with the highest severity and in the vineyard compared to the unburned soil. Overall, this study demonstrated that GRSP in soil is significantly affected by both severe fire and cultivation, and suggests that total amount of GRSP and GRSP distribution between the aggregate size fractions might be two reliable indicators of these types of perturbations of the soil environment.