Data from: "Arbuscular mycorrhizal dominated forests facilitate organic carbon stabilization in soil aggregates"

Tree mycorrhizal association types play a pivotal role in soil carbon (C)
accumulation. However, their effects on soil C stabilization remain
controversial, and the mechanisms of how mycorrhizal types affect
aggregate-associated soil organic carbon (SOC) are poorly understood. To
investigate how tree mycorrhizal associations affect aggregate-associated
SOC sequestration, we examined the soil aggregates, glomalin-related soil
protein (GRSP), soil respiration, and microbial traits from samples
collected in four arbuscular mycorrhizal (AM)- and four ectomycorrhizal
(ECM)-dominated stands. Additionally, we conducted a one-year mixed-litter
incubation experiment to determine the effect of mycorrhizal type on these
soil properties under controlled conditions. The results showed that
AM-dominated forests had 65.5% higher total aggregate-associated SOC than
ECM forests in the field, and that high-quality AM litter increased it by
16.5% compared to low-quality ECM litter in the incubation experiment. In
both field and laboratory studies, the total SOC accrual was mainly from
macroaggregate SOC changes, while GRSP and leaf chemical properties
contributed most to the SOC variation. The path model indicated that AM
tree species are positively and indirectly related to SOC through their
associations with litter chemistry, GRSP, soil aggregate stability, and
microbial traits in the field study. Additionally, field data showed that
soil microbial diversity and bacterial life strategies were associated
with the SOC accrual in AM forests. Synthesis. Our findings highlight that
AM-dominated forests have higher aggregate-associated SOC accrual through
macro-aggregate formation, along with higher litter quality, enhanced GRSP
levels, and shifts in soil microbial communities and life strategies.
These findings contribute to deepening our understanding of soil C
patterns in different mycorrhizal-dominated forest ecosystems and offer
critical insights for predicting and enhancing future forest C sinks.