Remote-sensing data reveals the response of soil erosion intensity to land use change in Loess Plateau, China

Developing an effective approach to rapidly assess the effects of restoration projects on soil erosion intensity and theirextensive spatial and temporal dynamics is important for regional ecosystem management and the development of soilconservation strategies in the future. This study applied a model that was developed at the pixel scale using water soilerosion indicators （land use, vegetation coverage and slope） to assess the soil erosion intensity in the Loess Plateau,China. Landsat TM/ETM＋ images in 2000, 2005 and 2010 were used to produce land use maps based on the object-oriented classification method. The MODIS product MOD13Q1 was adopted to derive the vegetation coveragemaps. The slope gradient maps were calculated based on data from the digital elevation model. The area of watersoil-eroded land was classified into six grades by integrating slope gradients, land use and vegetation coverage. Resultsshow that the Grain-To-Green Project in the Loess Plateau worked based on the land use changes from 2000 to 2010and enhanced vegetation restoration and ecological conservation. These projects effectively prevented soil erosion.During this period, lands with moderate, severe, more severe and extremely severe soil erosion intensities significantlydecreased and changed into less severe levels, respectively. Lands with slight and light soil erosion intensities increased.However, the total soil-eroded area in the Loess Plateau was reduced. The contributions of the seven provincesto the total soil-eroded area in the Loess Plateau and the composition of the soil erosion intensity level in eachprovince are different. Lands with severe, more severe and extremely severe soil erosion intensities are mainly distributedin Qinghai, Ningxia, Gansu and Inner Mongolia. These areas, although relatively small, must be prioritised andpreferentially treated.

Evaluation of soil erosion from chestnut forests: A case study in the Yanshan Mountains, China

Soil erosion from chestnut forests has many types and intensities. However, less attention has been paid to the increasing soil erosion in the chestnut forests of Yanshan Mountains region, North China. The objective of this study was to discuss forest ages(<5, 5~<10, 10~<20, and 20~ yr), slopes(5°~<15°, 15°~<25°, 25°~<35°, and 35°~), slope positions(upslope, midslope, downslope, and whole slope), and slope aspects(sunny, half-sunny, shade, and half-shade) effects on soil erosion types and intensities in chestnut forests. A field survey was applied to investigate in detail the contiguous chestnut forests near Changfu village of Hebei Province, China on October 9-30, 2016. Results showed that chestnut forests are dominated by moderate erosion in this region, and the soil erosionfrom chestnut forests tended to deteriorate gradually. The average land degradation index was 0.31. The erosion intensity from chestnut forests will gradually increase with the year of planting. Most of the slopes are greater than 15°, accounting for 86.7% of the total chestnut forests. Most of the chestnut forests occupy the whole slope, accounting for 47.5% of the total area. Moderate erosion occurs most commonly for different slope aspects. In conclusion, improving the preparation efficiency of chestnut forests and enhancing the construction standards of soil and water conservation measures would be useful measures to avoid soil erosion from chestnut forests reaching a more severe level.