Effects of bamboo-tea mixed model on surface soil organic carbon storage and components

Abstract

In order to explore the effects of planting tea trees under Phyllostachys edulis forest on soil organic carbon storage and carbon components, we took pure bamboo forest, bamboo-tea mixed forest and evergreen broad-leaved forest as the study objects, collected the surface soil (0-10 cm) of these three forest types, and measured soil organic carbon(SOC), carbon components, biotic and abiotic factors. The results were as follows: (1) The diversity of understory plants in bamboo-tea mixed forest was significantly lower than that in pure bamboo forest, but there was no significant differences in soil organic carbon density［(22.54 ± 2.09) t·hm-2］and carbon composition between bamboo-tea mixed forest and pure bamboo forest (P>0.05). Mineral-associated organic carbon (MOC) was (20.13 ± 1.83) g·kg-1, accounting for 92.66% of total organic carbon. The soil organic carbon density of evergreen broad-leaved forest was 41.15% and 41.00% higher than that of bamboo-tea mixed forest and pure bamboo forest (P>0.05). (2) Soil microbial biomass carbon (MBC) content, 16S rRNA gene abundance, cbbL gene abundance and microbial carbon use efficiency of these forest types were (0.58 - 3.08) g·kg-1, (2.18×1010 - 5.65×1010) copies·g-1, (0.37×108-1.10×108) copies·g-1, 0.03 - 0.28, respectively. But there were significant differences about these microbial indicators between three forest types (P>0.05). (3) SOC of the three forest types was significantly negatively correlated with soil pH, gravel content and aboveground litter biomass, and significantly positively correlated with soil clay content, silt content, total nitrogen, C∶N, total phosphorus and ammonium nitrogen (P<0.05). (4) In terms of different carbon fractions, particulate organic carbon (POC) and MOC were significantly negatively correlated with soil pH, gravel content and root biomass, and significantly positively correlated with soil water content, clay content, silt content, total nitrogen, C∶N, total phosphorus and ammonium nitrogen (P<0.05). In conclusion, the mixed transformation of bamboo and tea will cause the decrease of understory vegetation diversity in the original pure bamboo forest, but it will not cause the decrease of soil carbon storage; compared with evergreen broad-leaved forest, it is necessary to improve the management measures of bamboo to improve its carbon sink efficiency.

Keywords

• particulate organic carbon
• mineral-associated organic carbon
• soil orgnaic carbon density
• phyllostachys edulis forest
• bamboo-tea mixed forest