泰国北部山区土壤侵蚀调查报告

Investigation Report on Soil Erosion in Northern Mountain Area of Thailand

[目的]在泰国北部山区开展实地调查,研究该区土壤侵蚀特征,旨在为泛第三极暖湿区的土壤侵蚀预报和水土流失治理提供依据。[方法]以位于北部山区的清莱府为泰国土壤侵蚀典型区域的代表区域,选取18个调查单元(小流域/矩形区),于2018年11月22—29日调查了该区土壤侵蚀的类型与特征、土地利用类型及其空间分布、植被类型及盖度、耕地状况和作物类型、水土保持措施等。[结果]土壤侵蚀主要发生在道路、田地边坡、坡耕地(尤其是新耕种的坡地)和建设用地边坡,部分林下也可见侵蚀沟发育。未经硬化的土路大多存在不同程度的侵蚀,部分道路形成严重的侵蚀沟。坡耕地的侵蚀在新耕种的田块及其边坡处尤为严重,田块内部主要表现为细沟和浅沟侵蚀,以新近种植的菠萝地最为严重。林下土壤侵蚀主要出现在林下裸露的橡胶纯林内,甚至有浅沟和切沟出现。18个调查单元的平均土壤侵蚀模数介于480.9～3 565.3t/(km^2·a)之间,总体平均为1 767.9t/(km^2·a)。该区域土壤侵蚀模数及其空间变异的主控因素是地形因子。[结论]泰国北部山区虽有大面积的森林覆盖,但采用的水土保持措施相对简单,对开垦坡地的不合理利用引起了严重的人为加速侵蚀,加之该区地形复杂,导致土壤侵蚀严重威胁生态安全和粮食安全。同时,该区的土壤侵蚀基础观测资料缺乏,迫切需要加强土壤侵蚀的基础研究和基础数据的采集,提升对该区域土壤侵蚀过程与机理的认识,注重水土保持措施的综合运用,同时加强土壤培肥、污染防治和土壤保育等措施,保障泰国农业的可持续健康发展。

[Objective]This study investigated soil erosion characteristics in the northern mountain area of Thailand(Kingdom of Thailand)in order to provide evidence for soil loss prediction and control in the warm-wet area of the pan-third pole region.[Methods]Field survey was conducted in Chiang Rai Province from November 22 to 29 in 2018,and 18 sampling survey units/catchments were selected to investigate the types and characteristics of soil erosion,land use types and distribution,vegetation types and coverage,crop types,cropland conditions,and soil and water conservation measures.[Results]Soil erosion mainly occurred on roads,newly cultivated sloping croplands,the side slopes of cropland and construction sites,and even in some forests.Erosion gullies were found on most of the unhardened soil roads,and even on parts of the hardening roads.Sloping croplands,especially newly cultivated pineapple fields showed severe erosion,gullies and rills developed both in field and on its side slopes.Gully erosion in forest mainly occurred under pure forest with simple structure and little ground cover.Soil erosion rate ranged from 480.9 to 3 565.3 t/(km^2·a)with an average value of 1 767.9 t/(km^2·a).The slope length and gradient were the main factors affecting soil erosion of investigated units/catchments.[Conclusion]Severe soil erosion had significantly affected ecological security and food security in the northern mountain area of Thailand,which were mainly attributed to the irrational human activities such as deforest and reclamation,and the complicated terrain in this region.However,soil erosion control was limited by observation data shortage.Thus,there is an urgent need for the local government to enhance the understanding of the mechanism and process of soil erosion,to develop effective soil water conservation measures,to improve soil fertilization and control contaminants in soil,to ensure the sustainable and healthy agriculture in Thailand.