Glomalin-related soil protein analysis and its role in erodibility in a semiarid zone in San Luis Potosi, Mexico

The relationship between erodibility (susceptibility to erosion) and soil biological parameters has not been thoroughly investigated in Palomas Valley (PV), a region in San Luis Potosi, Mexico that includes gully-eroded microcatchments. Previous reports have shown the potential of Glomalin-related soil protein (GRSP) as an erodibility marker. Thus, our first goal was to develop an optimized autoclaving-free extraction method for GRSP suitable for 1D-SDS-PAGE analysis. Samples from horizon A (0–10 cm) were collected in three sites in PV. Total GRSP and organic matter contents were obtained, and GRSP was used for correlation analysis (Pearson correlation coefficient) with the K factor, an erodibility index. Our novel total protein-extraction method allowed to obtain moderated resolution electrophoretic patterns and GRSP detection was achieved by molecular weight comparison. GRSP contents ranged 11–203 μg·g−1 soil, and organic matter contents ranged from 2.1 to 12.8%. A multiple regression analysis was performed, obtaining a strong correlation (R = 0.79; R2 = 0.63) among organic matter and GRSP contents and K factor. The results suggested a strong dependence of K from organic components, mainly from GRSP. This is the first time that K factor and GRSP correlation analysis has been reported. Also, this work provides interesting data that could improve the analysis of factor K. All these results suggest GRSP content may play an important role in soil erodibility, but further research is required.