Soil Organic Carbon Stabilization in the Three Subtropical Forests: Importance of Clay and Metal Oxides

Abstract

Field observations show that subtropical forests can accumulate soil organic carbon (SOC) at high rate; however, the key mechanisms of SOC accumulation in subtropical forests remain unclear. Here we selected three typical subtropical forests with soil originated from same parent material under same climate condition in Dinghushan Biosphere Reserve, southern China: coniferous forest, mixed forest, and broadleaved forest with very different rates of SOC accumulation over the last three decades. To quantify the relative importance of physical versus chemical process on SOC stabilization in these forests, we used regression analysis to evaluate the relationship between the soil physical (clay, silt, and sand) and chemical (pH, Fe, and Al oxides) properties and SOC, and explored their respective contributions to SOC stabilization. Results showed that SOC stabilization was more strongly influenced by soil clay fraction through sorptive protection or microaggregate formation with SOC in the coniferous forest (r2 = 0.89, p < 0.05), and by chemical protection through forming organo‐mineral complexes in the mixed or broadleaved forest. Increasing carbon input was likely the main cause for SOC accumulation in the coniferous forest, but was not in the broadleaved forest. The strong linear relationships between SOC and Fe/Al oxides indicate that both the mixed (r2 = 0.63 and 0.57 with Feo and Alo, p < 0.05) and broadleaved forests (r2 = 0.96 and 0.78 with Fed and Alo, p < 0.05) on acid soils in southern China still have a great potential for further carbon sequestration in the future.

Tree carbon stock in middle mountain forest types: A case study from Chandragiri hills, Kathmandu, Nepal

“…This may be the consequence of basic ions in the muddy soil being washed out, which led to H + rich ions in the soil and more acid being generated by the decay of organic matter. SinceYu et al (2019) suggested that soil pH doesn't play a significant role in the accumulation of SOC, which strongly supports the present study. Soil organic carbon with Oak Forest found a strong positive correlation with the other two forest types which could be result from better nutrient input through litterfall and an increase in regenerating oak trees.…”

Response of leaf stoichiometry of Potentilla anserina to elevation in China's Qilian Mountains

“…Zonal climatic conditions could change soil nutrient flux and soil nutrient allocation by affecting vegetation composition, litter quality, and the exchange of matter and energy between the soil and the environment (Jiang et al, 2019 ). Likewise, under the combined influence of various factors, soil pH and SOC also changed with elevation (Yu et al, 2019 ; Zhu et al, 2019 ).…”

Nitrapyrin Addition Mitigated CO2 Emission from a Calcareous Soil Was Closely Associated with Its Effect on Decreasing Cellulolytic Fungal Community Diversity

“…Therefore, nitrapyrin may be more effective in controlling organic carbon transformation in soils with higher SOC and clay content. 42 Apart from these, the inhibitory effects of NI application on soil N transformation and Ncycling related microbial community are likely to impact the microbial processes of SOC decomposition. 12 Following this, Raza et al 8 found that the ability of DCD to reduce CO 2 emissions from calcareous soils in the Loess Plateau was closely associated with its ability to constrain soil nitrification and reduce AOB abundance.…”

“…For instance, Fisk et al showed that the added nitrapyrin was adsorbed by the soil organic matter, which led to reductions of its degradation rate and volatilization potential. Therefore, nitrapyrin may be more effective in controlling organic carbon transformation in soils with higher SOC and clay content . Apart from these, the inhibitory effects of NI application on soil N transformation and N-cycling related microbial community are likely to impact the microbial processes of SOC decomposition .…”