Wu Lei, Liu Xia, Yang Zhi, Chen Junlai, Ma Xiaoyi
Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
Blackland Research and Extension Center, Texas A&M AgriLife Research, Texas A&M University, Temple, TX, 76502, USA.
Environ Sci Pollut Res Int. 2021 Jul;28(28):38374-38392. doi: 10.1007/s11356-021-13274-1. Epub 2021 Mar 17.
Water erosion is one of the main types of soil degradation, but few quantitative estimates have been done in the soil erosion intensity grades of different landscape scaling characteristics in a large-scale ecological restoration watershed. This study comparatively illustrates the utility of high-resolution data and geospatial technique, particularly the GIS-based RUSLE model, for an improved understanding of the spatial patterns of soil erosion under different land use types, geomorphological styles, vegetational regionalizations, and geographical zonings, aiming to promote ecological sustainable watershed management in practice. Results indicate the following:(i) The soil erosion intensity grade showed an overall decreasing trend from northwest to southeast in the Jinghe River Watershed. The percentages of intense erosion and extremely intense erosion in different land use types in 2015 were significantly lower than that in 2000 except middle- and low-coverage grasslands because of the effective implementation of "Grain for Green" project. e.g., the percentage of extremely intense erosion in dry land decreased from 41.72% in 2000 to 8.99% in 2015.(ii) The mid-elevation loessial beams and hills and mid-elevation loessial tableland were both the major sources of intense erosion and extremely intense erosion, with the contribution ratio of 41.89 and 53.94% and 35.79 and 20.83% in 2000 and 44.45 and 48.99% and 36.88 and 18.72% in 2015, respectively.(iii) The intense, extremely intense and severe erosion in the temperate typical grassland subzone accounted for 32.62, 44.47, and 9.6% in 2000 and 36.74, 40.7, and 8.1% in 2015, respectively. There were no severe and extremely intense erosion in the deciduous oak forest subzone of northern and southern warm temperate. (iv) The intense, extremely intense, and severe erosion of the loessial wide valley hills accounted for 32.19, 45.27, and 8.92% in 2000 and 36.32, 41.42, and 7.48% in 2015. The intense and extremely intense erosion of the loessial tableland accounted for 40.58 and 16.02% in 2000 and 40.57 and 14.27% in 2015. More importantly, land use types can be applied to the design and implementation of a development scheme more reliably than other landscapes because the land use system is a more scientific and fine classification based on topography, soils, and vegetation correlated with geology, geomorphology, and climate. The knowledge on the fine landscape scale will be useful for comprehensive watershed management by soil scientists, agronomists, environmental scientists, land managers, and policymakers.
水蚀是土壤退化的主要类型之一，但在大规模生态恢复流域中，针对不同景观尺度特征的土壤侵蚀强度等级，很少有定量评估。本研究比较说明了高分辨率数据和地理空间技术，特别是基于GIS的RUSLE模型，对于更好地理解不同土地利用类型、地貌样式、植被分区和地理分区下土壤侵蚀的空间格局的作用，旨在推动实践中的生态可持续流域管理。结果表明：（i）泾河流域土壤侵蚀强度等级总体上呈现出从西北向东南递减的趋势。由于“退耕还林还草”工程的有效实施，2015年不同土地利用类型中强烈侵蚀和极强烈侵蚀的比例，除中低覆盖度草地外，均显著低于2000年。例如，旱地中极强烈侵蚀的比例从2000年的41.72%降至2015年的8.99%。（ii）中海拔黄土梁峁和中海拔黄土塬均是强烈侵蚀和极强烈侵蚀的主要来源，2000年的贡献率分别为41.89%和53.94%、35.79%和20.83%，2015年分别为44.45%和48.99%、36.88%和18.72%。（iii）温带典型草原亚区的强烈、极强烈和严重侵蚀在2000年分别占32.62%、44.47%和9.6%，2015年分别占36.74%、40.7%和8.1%。暖温带北部和南部的落叶栎林亚区没有严重和极强烈侵蚀。（iv）黄土宽谷丘陵的强烈、极强烈和严重侵蚀在2000年分别占32.19%、45.27%和8.92%，2015年分别占36.32%、41.42%和7.48%。黄土塬的强烈和极强烈侵蚀在2000年分别占40.58%和16.02%，2015年分别占40.57%和14.27%。更重要的是，与其他景观相比，土地利用类型可更可靠地应用于开发方案的设计和实施，因为土地利用系统是基于与地质、地貌和气候相关的地形、土壤和植被进行的更科学、精细的分类。关于精细景观尺度的知识将有助于土壤科学家、农学家、环境科学家、土地管理者和政策制定者进行全面的流域管理。
