四川省安宁河流域土壤侵蚀时空演变及预测分析

Spatial-temporal evolution and prediction of soil erosion in Anning River Basin,Sichuan Province

为了解安宁河流域土壤侵蚀变化及未来发展状况,以修正土壤侵蚀方程为基础,对该地区1995~2018年各年份土壤侵蚀模数进行计算与分级,结合转移矩阵、斜率变化和CA-Markov模型对其时空演变和发展规律进行分析。结果表明:①各等级侵蚀区栅格占比为微度>轻度>中度>强烈>极强烈>剧烈,轻度及以下等级侵蚀区栅格累加比例达到全域的70%以上,流域整体处于中等侵蚀水平;②流域土壤侵蚀整体呈现西部和南部相对严重的分布变化;③23 a内,微度、轻度和剧烈等级的稳定性均较强,分别有83.58%,81.09%和68.73%的区域等级未发生改变,仅微度向更高等级转换,其他等级均向更低等级转换;④斜率变化及显著性检验显示,整个流域有94.35%的区域土壤侵蚀状况未发生明显改变,仅有0.39%的地区侵蚀状况显著加重;⑤预测结果及精度检验表明,CA-Markov模型适用于地区土壤侵蚀发展预测,2021年流域土壤侵蚀整体呈现良好发展的趋势。研究结果可作为区域土壤侵蚀综合治理提供重要的科学参考依据。

In order to understand the changes in soil erosion and future development of the Anning River Basin,we completed the calculation and grading of the soil erosion modulus of the region from 1995 to 2018 by the revised soil erosion equation,and the temporal and spatial evolution and development of soil erosion in the region were analyzed by using transfer matrix,slope change and CA-Markov model.The results show that:(1)the proportion of grids in each erosion level from high to low were micro,slight,mild,strong,very strong and severe.The accumulative proportion of grids of below slight levels had reached more than 70% of the whole area,and the overall soil erosion of the basin was at a medium level.(2)The overall soil erosion of the basin presented a relatively severe distribution change in the west and south.(3)During the 23 years,the micro,slight and severe levels of erosion were stable,83.58%,81.09% and 68.73% of areas were not changed respectively.Only the micro level was converted to a higher level,and the other levels were all converted to lower levels.(4)Slope change and significance test showed that 94.35% of the soil erosion in the whole area did not change significantly,and only 0.39% of the area was significantly worse.(6)Prediction results and accuracy tests showed that the CA-Markov model was suitable for the prediction of regional soil erosion development.In 2021,the overall soil erosion in the watershed showed a good development trend.The study can be used as a reference for comprehensive management of regional soil erosion.