苏打盐碱化土壤pH与团聚体中球囊霉素相关土壤蛋白含量的关系

球囊霉素相关土壤蛋白(Glomalin-related soil protein,GRSP)在土壤团聚体形成中起重要作用,与土壤团聚体稳定性正相关。土壤盐碱化破坏土壤结构,降低土壤中GRSP含量,但影响多大尺寸团聚体GRSP含量并不清楚。本文采集45个松嫩盐碱化草地土壤样品,通过干筛法分离出直径0.25、0.25~1和1~2 mm 3种不同粒级团聚体,采用Bradford法测定土壤中GRSP含量,并测定土壤盐碱化指标,经Pearson相关分析和前向选择变量多元线性回归分析,结果显示:土壤pH显著影响各粒级团聚体总球囊霉素相关土壤蛋白(T-GRSP)含量和难提取球囊霉素相关土壤蛋白(DE-GRSP)含量,二者存在显著负相关关系,特别是0.25~1 mm粒级团聚体DE-GRSP含量与土壤pH存在极显著负相关关系,可解释22.3%的DE-GRSP含量变化。土壤pH、电导率、碱解氮和有效磷对各粒级团聚体易提取球囊霉素相关土壤蛋白(EE-GRSP)影响不显著。结果表明土壤苏打盐碱化影响0.25~1 mm团粒结构中较稳定的DE-GRSP含量,可能对土壤团聚体胶联和土壤碳存储产生负影响。

Soil pH Effect on Glomalin-related Soil Protein in Aggregates in Sodic-saline Soil

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 not still clear in decreasing GRSP from which size. In this paper, 45 soil samples from Songnen grassland were collected 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 size fractions, at the same time, soil physicochemical 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. Significant negative relationship was between soil pH and total-GRSP (T-GRSP), difficultly-extractable GRSP (DE-GRSP). Especially, highly significant negative correlation was found between soil pH and DE-GRSP from 0.25~1 mm size, could be explained 22.3% variation of DE-GRSP. No relationship was found between soil pH value, electrical conductivity, available nitrogen, available phosphorus and GRSP contents. The results showed that sodic salt induced decreased in DE-GRSP of 0.25~1 mm size soil aggregation, it is possible to have a negative impact on aggregate binding and soil carbon storage.