Relationships between the amount of microbial biomass and the physicochemical properties of soil - comparison between volcanic and non-volcanic ash soils.

摘要

The microbial biomass and some physicochemical properties of 9 volcanic ash soils and 7 non-volcanic ash soils in Japan were measured and their relationships analysed. The results showed: (1) the amounts of biomass C and N did not significantly differ between the volcanic (58-1504 mg C/kg, 10-180 mg N/kg) and non-volcanic ash soils (11-1118 mg C/kg, 2-124 mg N/kg); (2) in both soils, the amounts of biomass C and N showed significant relationships (r ?0.826, n = 7) with organic C content, total N content, total humus content, NaOH-extracted humic acid content, NaOH-extracted fulvic acid content and Al2O3 content. The relationships between the amounts of biomass C and N and the CEC and phosphate absorption coefficient were significant (r ?0.809, n= 9) only in volcanic ash soils, and the relationship between the amount of biomass and clay content was significant (r ?0.839, n = 7) in non-volcanic ash soils. The soil characteristics having significant relationships (r ?0.902, n = 9) with the amount of biomass also showed significant relationships (r ?0.827, n = 7) with fulvic acids, total humus, humic acids or organic C contents; and (3) the relationships between the amounts of biomass C and N and several soil characteristics such as organic C,total N, total humus, fulvic acids, humic acid content, CEC, phosphate absorption coefficient and Al2O3 content can be separated into the volcanic ash soil group and the non-volcanic ash soil group.