Organic carbon and its oxidation stability characteristics of shallow soil in frozen soil area of Three River Source Region北大核心CSCD

As the most important part of the global carbon cycle，soil carbon pool is the largest carbon pool in terrestrial ecosystems. Soil carbon pool in permafrost regions is the most sensitive carbon pool to climate change. Weak climate change will have a huge impact on the organic carbon production in the shallow soil，and then affect the regional landscape and ecology. As an indicator reflecting the antioxidant capacity of soil organic carbon，oxidation stability affects the quantity and quality of soil organic carbon，and its variation has a certain regularity in the alpine permafrost region under the influence of climatic factors. In order to explore the distribution characteristics of soil organic carbon and its oxidation stability in frozen soil，based on the experimental data and the climatic data from 2011 to 2019，the random forest model was used to conduct multi-factor digital mapping on soil organic carbon content，soil organic carbon components with different oxidation difficulty degrees，and soil organic carbon oxidation stability coefficient and environmental variables（average annual precipitation，average annual sunshine hours，average annual air temperature，and altitude）and analyze the controlling factors. The results showed that the model had an interpretation degree of more than 54% for the shallow soil organic carbon in frozen soil area of Three River Source Region，and the digital mapping could reflect the distribution of soil organic carbon well. Soil organic carbon was mainly affected by precipitation and sunshine duration，and temperature took second place. The spatial distribution of components with different oxidation difficulty is different，but the oxidation stability has the distribution characteristics of high in the north and low in the south. Cold and dry are conducive to improving the oxidation stability of organic carbon in shallow soil of frozen soil area. © 2022 Science Press (China).

Organic carbon and its oxidation stability characteristics of shallow soil in frozen soil area of Three River Source Region

As the most important part of the global carbon cycle， soil carbon pool is the largest carbon pool in terrestrial ecosystems. Soil carbon pool in permafrost regions is the most sensitive carbon pool to climate change. Weak climate change will have a huge impact on the organic carbon production in the shallow soil， and then affect the regional landscape and ecology. As an indicator reflecting the antioxidant capacity of soil organic carbon， oxidation stability affects the quantity and quality of soil organic carbon， and its variation has a certain regularity in the alpine permafrost region under the influence of climatic factors. In order to explore the distribution characteristics of soil organic carbon and its oxidation stability in frozen soil， based on the experimental data and the climatic data from 2011 to 2019， the random forest model was used to conduct multi-factor digital mapping on soil organic carbon content， soil organic carbon components with different oxidation difficulty degrees， and soil organic carbon oxidation stability coefficient and environmental variables （average annual precipitation， average annual sunshine hours， average annual air temperature， and altitude） and analyze the controlling factors. The results showed that the model had an interpretation degree of more than 54% for the shallow soil organic carbon in frozen soil area of Three River Source Region， and the digital mapping could reflect the distribution of soil organic carbon well. Soil organic carbon was mainly affected by precipitation and sunshine duration， and temperature took second place. The spatial distribution of components with different oxidation difficulty is different， but the oxidation stability has the distribution characteristics of high in the north and low in the south. Cold and dry are conducive to improving the oxidation stability of organic carbon in shallow soil of frozen soil area.