The estimation of soil organic carbon content（SOC） is one of the important issues in the researches of global carbon cycle.However

the estimated magnitude of SOC exist great differences among different scientists.There are two commonly used methods for the estimation of SOC

each method having both advantage and disadvantage.One of the methods is so called direct method

which is based on the samples of measured SOC and maps of soil or vegetation types.The other is so called indirect method

which is based on ecosystem process model of carbon cycle.The disadvantage of direct method is that it mainly discloses the difference of SOC among different soil or vegetation types

so it can hardly distinguish the difference of SOC in the same type of soil or vegetation.The indirect method

process-based method

bases on the mechanics of carbon transfer in the ecosystem and then could potentially improve the spatial resolution of the SOC estimation if the input variables have high spatial resolution.However

due to the complexity of the process-based model

the model usually simplifies some key model parameters that have spatial heterogeneity with constants.So this simplification will produce a great deal of uncertainties in the estimation of SOC

especially on the spatial precision.In this paper

the authors combined the process-based model（CASA model） with the measured SOC

in which the remote sensing data（AVHRR NDIV） was incorporated into the model to enhance the spatial resolution.To model the soil basal respiration

the Van’t Hoff model was used to combine with CASA model.The results showed that this method could significantly improve the spatial precision（8km spatial resolution）.The results also showed that the relationship between soil basal respiration and SOC is very well

as the influence of environmental factors

i.e.temperature and moisture

have been removed from soil respiration

which makes the SOC become the most important factor of soil basal respiration.The statistic model of soil basal respiration and SOC showed that the determinant coefficient（R

2

） is 0.78.As the method in this paper contains advantages from both direct and indirect method

so it could significantly improve the spatial resolution and

at the same time

keep the estimation of SOC well matched with the measured SOC.