Urbanization-induced glomalin changes and their associations with land-use configuration, forest characteristics, and soil properties in Changchun, Northeast China

Abstract

Purpose

Glomalin-related soil protein (GRSP), produced by arbuscular mycorrhizal fungi, plays crucial roles in the global carbon cycle and improves soil quality. However, information on GRSP and its contribution to the soil organic carbon (SOC) pool in the process of urbanization is limited.

Materials and methods

In this study, easily extracted GRSP (EE-GRSP) and total GRSP (T-GRSP) were analyzed in an urban-rural gradient, and a detailed survey of greenspace characteristics (soil properties: pH, electric conductivity [EC], bulk density, temperature, and SOC; forest characteristics: tree density, tree size, tree species, and arbor and shrub richness; land use: road, building, greenspace, and wetland and water) in 306 plots was undertaken.

Results and discussion

EE-GRSP/SOC and T-GRSP/SOC decreased significantly by 10% in urban plots when compared with the rural plots. From the rural to urban plots, decrease in pH and increases in SOC, EC, tree height, and under branch height (p < 0.01) were found in this study. These changes in greenspace characteristics were responsible for variation in GRSP, while their relative explanatory power differed (soil properties: 43.8%, forest characteristics: 25.7%, and land use: 18.6%). Forward selection analysis identified that EC, greenspace proportion, pH, shrub richness, diameter at breast height, wetland and water proportion, bulk density, and under branch height had significant explanatory power for the variation in GRSP (all: p < 0.05).

Conclusions

Our findings indicate that urbanization greatly affects the contribution of GRSP to the SOC pool. The changes in greenspace characteristics played key roles in regulating the pattern of GRSP, especially soil properties. The results of this study may be used as a reference for the exploration of GRSP in urban environments and implementation of soil improvement practices by regulating GRSP.

from Energy Ecology Environment Ambio via Terpsi Hori on Inoreader http://bit.ly/2S6YSyo