| Soil erosion is occurring strongly and it is the critical environmental threat. Over the last 4 decades, erosion has resulted in the disappearance of one-third of total land in the world. The erosion rate is expected to be governed by land use and soil cover. Among land cover types, the role of planted forest should be further discussed. Although previous studies has shared the same point of view that vegetation cover has the negative correlation with soil erosion but it should be noted that the various vegetation types, forest structures and plantation development stages may have different impact in eliminate soil erosion. Beside, runoff also strongly determine the amount of soil loss under plantation forest. However, for decades, many studies have strong emphasis on the effect of plantation cover on controlling erosion while runoff and runoff coefficient were not sufficiently concerned. If the impact of land use change only limited to erosion, it cannot fully reveal the water erosion process and resolve the question about the interaction among rainfall, overland flow, sediment loss and different land use purposes. Monitoring both overland flow and soil erosion, as well as how the soil cover change govern these two aspects are very necessary.<br>
In the recent decades, Acacia plantation model has been rapidly emerged and expanded in the rural area of Vietnam, especially in the mountainous provinces. The changing of land use purpose in large scale may lead to the rapidly degradation of soil and water resources. Beside the benefits that Acacia plantation bring back, the impact of this land use type on the hydrological processes inside is also need to be concerned. Previously, there are a while range of studies which focus on the role of Acacia planted forest in soil protection, however it is important to assess both the ability to regulate overland flow and soil loss, especially for Acacia at different ages. This study is conducted to determine the response of runoff generation and erosion to different land use, to elucidate the relationship between runoff, erosion and rainfall factor and to compare the result of runoff and erosion from this research to ones from other previous study on other land use types. Our finding may help reducing the negative effect of Acacia plantation model on soil and water resources in the headwater of Vietnam. |
