攀枝花干热河谷区环境对水分的影响

Effects of environment on soil water in dry-hot valleys of Panzhihua

以'水分'为核心,通过对区域气候、土壤水源涵养功能、植物的耗水特点和土壤水分动态4方面的分析,提出攀枝花干热河谷植被恢复的一些关键技术.得出:1)旱季水热的非同步性是植被恢复困难的所在;坡向导致的微气候差异是干热河谷阴坡、阳坡植被分异的主要原因.2)攀枝花干热河谷地段粗骨性红壤土层浅薄,蓄水能力较弱,土壤层饱和蓄水量和稳渗率分别为3.8～5.0 mm/cmm土层、0.77～4.72 mm/min),土壤有效水约为饱和蓄水量的50%.3)该土壤母质因其特殊性,仍有较强的蓄水能力,饱和蓄水量(1.8～2.8mm/cm土层)和人渗率(0.13～0.26 mm/min)虽低于土壤层,但其有效蓄水量却与土壤层相近.4)深层土壤,特别是母质层水分数量对维持植物旱季生存有着重要的意义.因此,增加土层厚度、提高土壤,特别是母质层的入渗能力是该类土壤植被恢复的关键技术措施.5)不同植物旱季日均耗水量差异较大,树种的合理配置与否直接影响植被恢复成效.目前该区营造的麻疯树、番麻、构树、加纳比松、车桑子和台湾相思均具有较强的耐早能力.

The deficiency of soil water in dry season was the main limited factor for restoration of vegetation in dry-hot valleys.In this paper,focusing on the water environment,some key approaches for the restoration of vegetation in the area of Panzhihua were advanced according to four aspects with the regional climate,water-holding capacity of soil,the water-consuming feature of vegetations and dynamics of soil water,and some main conclusions were also made as follows.(1) The difficulty in restoration of vegetation mainly owed to non-synchronization between water and temperature in the dry season.The climate difference of microenvironments,such as amount of evaporation determines distribution and type of vegetation.(2) The water-holding capacity of the red soil with more gravel is poor owing to bad soil structure and thin depth of soil layer.Saturated storage and infiltration ratio of soil are respectively 3.8-5.0 mm with every centimeter soil layer and 0.77-4.72 mm/min,but amount of the available water is only 50% of saturated water in soil layer.(3) Because of its particularity possessed by this soil,saturated storage and infiltrative ratio of parent material layer were both less than soil layer,and there were the same amount of available water in two layers.(4) The water in deeper soil,especially in parent material layer played a crucial role in maintaining existence of the vegetation in dry season.Therefore,to add he thickness of soil layer and improve infiltrative ratio of parent material layer were important technical measures for the restoration of vegetation in the red soil.(5) The dayly water-consuming amount in dry season was considerable difference among tree species for forestry,and the rational structure collocation of tree species was a key for restoration of vegetation.Presently,plants practically afforested such as Jatropha curcas,Pinus caribaea,Dodonaea viscosa,Acacia dealbata,India neem,Lantana camara,Broussonetia papyrifera have strong capacity of tolerance to drought.