T.T. Nguyen, C.T. Tran and H.H.V. Nguyen
Abstract
Reliably determining soil erosion and sediment regulation services of each landscape or ecosystem was a challenge, and of enormous significance for natural protected areas. The study aimed to explore the application of the In VEST-SDR model to estimate the soil loss, sediment retention, and sediment export in the O Lau basin, and to quantify the soil erosion and sediment regulation services of natural forest landscapes in 2010, 2015, and 2023. The model was applied successfully in the O Lau basin, Vietnam covered by a significant part of the Phong Dien protected area. The results showed that the k parameter is the most sensitive to the model, followed by the C factor. The k, maximum SDR, and IC0 values determined in the period 2015 - 2019 and 2020-2023 were 1, 0.8, and 0.61; 1.8, 0.8, and 0.57, respectively. The modelâs performance was good, with an index of agreement of 0.87. The amount of avoided soil loss and avoided sediment delivery of seven natural forest landscapes in the study area was 2,409,728 tons and 53,021 tons in 2010, 1,368,556 tons and 30,072 tons in 2015, 3,057,393 tons and 278,493 tons in 2023. The natural forest landscapes on ferralitic soils got the greatest regulation services. The results provide confident scientific bases to annually value the regulation services in the form of money.