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Soil organic carbon storage and profile inventory in the different vegetation types of Luya Mountain

2011; Elsevier BV; Linguagem: Inglês

1000-0933

Tian Xu-ping,

Forest, Soil, and Plant Ecology in China

The patterns and controls of soil organic carbon(SOC) storage are critical for our understanding of the biosphere,given the importance of SOC for ecosystem process and feedback of this pool to atmospheric composition and the rate of climate change.Understanding the distribution of organic carbon inventories in soil profile is crucial for assessing regional,continental and global soil C storage and predicting and ameliorating the consequences of global change.This study was conducted to determine the soil organic carbon inventories of 0-1.0m depth at 21 plots in four vegetation types from 1703m to 2756m in Luya Mountain.The four vegetation types were subalpine meadow(SM),cold-temperate needleleaf forest(CNF),coniferous and broad-leaved mixed forest(CBF) and shrub-grassland(SG)(former cropland).The results showed that the profile distribution of SOC was different under different vegetation types,indicating the effect of vegetation on SOC.The SOC storage in the profiles decreased generally with increasing depth under the four vegetation types,with sharp reduction at the depth of 20cm for SM,50cm for CNF,20cm for CBF and 40cm for SG.The maximum SOC storage occurred at the depth of 10—20cm in most cases.The four vegetation types had no significant difference for SOC storage at the 0—10cm soil profile.The SOC content of the SM was closer to that of SG at all the soil profiles,but was significantly higher than that of CBF and lower than that of CNF at the 20—50cm soil depth.The SOC storage was positively correlated with soil total nitrogen and water content,but negatively with bulk density.Soil organic carbon was significantly related with clay and silt content in deeper soil layers.The result of stepwise linear regression analysis showed that the SOC storage was correlated with total nitrogen,water content and bulk density for SM,with TN for CNF,TN and BD for CBF and BD for SG.Within 50 cm depth,the SOC storage was 13.564,11.827,9.461,9.111 kg/m2 for SM,CNF,CBF and SG respectively.The SOC storage in SM was significantly greater than in CBF and SG(P=0.031 and 0.021) within 50 cm depth,while there was no significant difference among the four vegetation types within 20 cm depth.There was an apparent trend that the soil organic carbon storage increased with increasing altitude(R2=0.299,P=0.01).