Spatial Temporal Pattern of Soil and Water Conservation Function in Trans-boundary Area of Yalu River Basin

Taking trans-boundary area of Yalu River Basin as the study area, based on multi-source data, remote sensing interpretation, InVEST model are used to quantitatively analyze the changes of soil and water conservation functions in the Yalu River Basin from 1988 to 2018, and the trade-off or synergistic relationship between them was discussed. The results show that forestland and cropland are the dominant land use type in the Yalu River Basin. In 2018, the areal percent of forestland is 76.78% and 75.84% on the China side and the North Korea side, respectively; the areal percent of cropland is 20.02 % and 21.63 % on the China side and the North Korea side, respectively; in the past 30 years, the change rate of paddy field area in the basin was the largest, the wetland area increased 330.63 % and 127.52 % on the China side and the North Korea side, respectively. With land use changes, the water yield increased by 118.40×10⁸ mm and 33.76×10⁸ mm on the China side and the North Korea side, respectively; the soil conservation decreased by 111.71×10⁸ t, 102.61×10⁸ t on the China side and the North Korea side, respectively. From 1988 to 2018, the water and soil conservation function showed a synergetic relationship and a synergy−trade-off−synergy relationship on the China side and the North Korea side, respectively. This study provides important data for the function improvement and sustainable development of basin ecosystem.