Accumulation of glomalin-related soil protein benefits to soil carbon
sequestration with tropical coastal forest restoration
Abstract
Reforestation is widely used to restore degraded infertile soils in the
coastal area. Substantial attention has been paid to the functioning of
AMF in vegetation restoration because arbuscular mycorrhizal fungi (AMF)
are considered beneficial to this process. However, little is known
about the effect of AMF product, glomalin-related soil protein (GRSP),
on soil organic carbon (SOC) sequestration during the forest
restoration. We conducted a study in a tropical region where the native
forest has been seriously deforested with only a few grasses and then a
series of restoration approaches have been made to restore the forest
ecosystem. The study sites include a barren land (BL), a Eucalyptus
exserta planted forest (EF), a mixed broadleaved forest (MF) and a
secondary natural forest (SF), which represents the un-, early-, middle-
and late-restoration stage, respectively. The results showed that the
restoration increased EE-GRSP and T-GRSP by 3.9-12.3 times and 1.9-4.6
times compared with the barren land, respectively. The proportion of
GRSP in SOC is 1.6-2.0% (EE-GRSP/SOC) and 6.5-15.8% (T-GRSP/SOC),
respectively. Also, a significantly positive relationship was found
between the proportion of GRSP in SOC and recalcitrant SOC composition
percentage (aromatic C), as well as between GRSP and soil aggregate
stability. These results together suggest that the restoration of the
degraded tropical forest is beneficial to soil C sequestration with the
accumulation of GRSP, most likely, through an improvement of the soil
aggregate stability and increase of the proportion of recalcitrant soil
C chemical composition.