南流江流域森林土壤保持功能变化分析

Analysis on Changes of Forest Sediment Retention Func tion in Nanliujiang River Basin

以广西北部湾南流江流域为研究区,利用2009、2014和2019年的森林资源二调数据与森林资源管理“一张图”数据,结合ArcGIS和InVEST模型,定量评估南流江流域的土壤保持量,并利用实测数据进行验证。结果表明:2009—2019年间,研究区土壤保持功能持续增强,土壤保持量增幅达100.8%。各林地类型单位面积平均土壤保持量呈增长趋势;2009—2019年间,研究区桉树、阔叶树、竹林土壤保持总量呈现递增的趋势,经济林、杉木和松类呈现递减的趋势,各森林景观类型的平均土壤保持量大小为杉木>松树>阔叶树>桉树>经济林>竹林;研究区土壤侵蚀比较严重的地区分布比较分散,主要分布北流市的北部、玉州区的西部和东北部、陆川县的北部、博白县的中部、浦北县东北部地区。为增强流域土壤保持功能,可改变林分结构、发展松杉桉混交的营造林模式,提高森林质量,优化森林土地利用景观格局,完善相关的工程措施等。

Taking the Nanliujiang River basin in Gulf of Tonkin,Guangxi as the study area,using the secondary survey data of forest resources in 2009,2014 and 2019 and the″One map″data of forest resources management,combining ArcGIS and InVEST models,quantitative assessment of soil conservation in the Nanliujiang River basin,and the use of field data to verify.The results showed that the soil conservation function was continuously enhanced and the soil conservation amount increased by 100.8%from 2009 to 2019.From 2009 to 2019,the total amount of soil conservation of eucalyptus,broad-leaved tree and bamboo forest showed an increasing trend,economic forest,Chinese fir and pine showed a decreasing trend.The average soil conservation amount of each forest landscape type was Chinese fir&GT In the study area,the distribution of serious soil erosion is scattered,it is mainly distributed in northern Beiliu,western and northeastern Yuzhou District,northern Luchuan County,Central Bobai County and northeastern Pubei County.In order to enhance the soil conservation function of the watershed,it is necessary to change the stand structure,develop the mixed planting pattern of pine and fir,improve the forest quality,optimize the landscape pattern of forest land use,and perfect the related engineering measures.