###### Abstract  
Soil erosion is a key factor in soil quality degradation and carbon balance in arid ecosystems. However, many models ignore the soil erosion process in arid regions, which may lead to limits in our understanding of ecosystem processes in arid regions. In this study, we added the soil erosion process according to field observed data of soil hydrothermal regimes and carbon flux. We validated this coupling version of IBIS (Integrated Biosphere Simulator) and RUSLE (RU-IBIS) by examining four different vegetation types and the carbon budget in the arid region on the Loess Plateau (LP). Our results indicated that the coupling model (RU-IBIS) produced more reliable simulations of the soil water content (with the r from 0.23-0.90 to 0.71-0.97) and evaporation (ET) (the average r was 0.76) and significantly improved the simulation of the leaf area index (LAI) (the average r was 0.95) and net primary production (NPP) (the average r was 0.95). We also conducted sensitivity experiments to determine how soil texture and aerodynamic roughness (Z\({}_{\text{6m}}\)) affect the soil water content. Moreover, it was revealed that specific leaf area (SLA) plays a key role in the simulation of NPP and NEE. Our study suggests that the coupled soil erosion process and parameterization can effectively improve the performance of IBIS in arid regions. These results need to be considered in future Earth system models.  
IBIS; RUSLE; soil water content; soil erosion process; carbon cycle; Loess Plateau 1  
cycle in arid regions. Soil erosion must be included in the study of the carbon cycle in arid regions [14; 15]. However, in many DVGMs, this process has only been expressed as simple soil erosion parameterization schemes [16; 17; 18].  
IBIS was developed to illuminate the interactions between different biosphere factors on time scales relevant to the carbon cycle process [19]. In recent years, some studies have started to apply IBIS on a global scale [20]. Further refinements of the IBIS model include the creation of IBIS 2.0 and Agro-IBIS [21; 22; 23], which incorporate other models of atmospheric circulation, agricultural vegetation, and hydrological processes. In terms of model improvement, [PERSON] et al. (2005) combined IBIS with the nitrogen cycle model to simulate the regional nitrogen cycle and to reveal the extent to which the nitrogen cycle affects the ecosystem [24]. While most ecosystems examined with IBIS are forests and farmland [25; 26; 27], recent updates to IBIS include adding more vegetation types and statistical models [28; 29]. However, the IBIS model does not consider changes to the soil erosion regime. The absence of this process may produce model results that overestimate the moisture and carbon budget in arid regions.  
It is important to use the DVGM to model the carbon cycle in arid ecosystems. Therefore, the main contents of this study include (1) incorporating the revised universal soil loss equation (RUSLE) into the soil erosion and verifying the accuracies of modeling soil water content, LAI, and NPP simulations in the Loess Plateau (LP) and (2) determining the sensitivity of the soil hydrothermal regime, ET (evapotranspiration), and the carbon flux to the changing model parameters. The modified IBIS model provides a useful tool for understanding the carbon cycle of arid regions in warming climate conditions.