Estimation of Applicability of Soil Model for Rubber (Hevea brasiliensis) Plantations in Xishuangbanna, Southwest China

Abstract

Soil water content (SWC) plays a vital role in the process of evapotranspiration (ET) in rubber plantations. To investigate the influence of the ET process on soil water balance in rubber plantations, we measured SWC at depths of 10, 20, 30, 40, 70, 100, 130 cm, measured the characteristics of root density distribution, and estimated the ET and deep percolation at a rubber plantation in Xishuangbanna using the Hydrus-1D model. Our results indicate the Hydrus-1D model can accurate simulate soil water dynamics in the 0–130 cm of rubber plantations with Nash-Sutcliffe Efficiency Coefficient (NSE) was 0.80–0.96, the Root Mean Squared Error (RMSE) was 0.05–0.02, and the Pearson Correlation Coefficient (R) was 0.82–0.97. Obviously, there were seasonal variation characteristics in soil moisture changes in the rubber plantations of Xishuangbanna. The soil water storage (SWS) dropped to its lowest value of 194 mm and reached its maximum value of 504 mm from the dry season to the rainy season. The simulated ET of the rubber plantation was 1166.1 mm. The large uptake and utilization of soil water by rubber plantations in the dry season affects or exacerbates seasonal drought in Xishuangbanna and leads to a shortage of regional water resources.