Abstract:Glomalin-related soil protein (GRSP) is regarded as an important binding agent in soil aggregation, and a positive relationship between GRSP concentration and aggregate stability has been demonstrated. Soil salinization and alkalinization destroys soil structure, induces decreasing of GRSP concentration, but it was still unclear in decreasing GRSP in which size of aggregates. In this paper, 45 soda-saline soil samples were collected from Songnen grassland and dry-sieved into the following size classes: <0.25 mm, 0.25-1 mm and 1-2 mm. Bradford reagent was used to determine GRSP contents of each aggregate size fractions, at the same time, soil physico-chemical properties about salt were also determined. Pearson correlation and multiple linear regressions with forward selection were performed in order to test the significance of influence. The results showed that significant negative relationships were existed between soil pH and total-GRSP (T-GRSP), and difficultly-extractable GRSP (DE-GRSP). Especially, highly significant negative correlation was found between soil pH and DE-GRSP from 0.25–1 mm size, which could be explained 22.3% variation of DE-GRSP. No relationship was found between soil pH value, electrical conductivity, available nitrogen, available phosphorus and easily-extractable GRSP (EE-GRSP) contents. The results showed that sodic salt induced decreased in DE-GRSP of 0.25-1 mm aggregates, it is possible to have a negative impact on aggregate binding and soil carbon storage.