宁夏沙地立地分类评价和适地适树的研究

<正> 1.沙地立地分类的原则和系统1.1分类的原则a.多因子立地分类原则:在沙区不同地域的生态环境因子的组合是有差异的,这些因子包括气候、地质、地貌、土壤、水文以及沙丘的部位等均能决定各种植物的生存和发展,相似的生态因子产生相似的植物群体和生长量,即植物能反映生态条件量和质的特征,立地分类及评价原则正是以区别各种具有相似生态因子组合的不同地段划分类型,按

APPRAISAL OF SITE CLASSIFICATION OF SANDY GROUND & RESEARCH ON TREE SPECIES SUITABLE FOR DIFFERENT SITE TYPES IN NINGXIA

This paper takes the ecologic theory of forest as the basis, thinking over the regionclassificatory law of sandy ground in Ningxia, combining many-year productional experi-ments and lessons to establish grade-5 site classificatory system of sandy ground in Ningxiaand defining one site region, one site zone, three site kinds, eleven site type groups and thir-ty four site types. The quantitative theory was applied to draw up the quantitative table of the sites. Tak-ing the landforms, the sand-shifting condition, the size of sand dune, the place of a sanddune, the months of investigation, age, height, crown cover, the basal diameter of aerialpart and so on as the independent variable, taking the biomass of grow thickly as the depen-dent variable to draw up the quantitative table of Caragana korshinskii K., Carganaintermedia K., Hedysarm scoparium F., Salix cheilophyssa S.. This paper adopted the theoryof quanlity the quantity, Engaging comprihensive calculation and analysis on the site typeof sandy ground in Ningxia.