THE UTILIZATION OF TROPICAL SECONDARY FOREST AND THE CHANGE OF SOIL PHYSICAL PROPERTIES
热带次生林利用与土壤物理性质变化

By Using the data from the long term ecological observational station in forest region of Diaoluo Mountains, Hainan island,and by testing physical properties of soil sampled periodically,the effects of different secondary forest felling intensity and utilization ways,including quadrats of secondary forest control,selective felling 50% selective felling70%.clear felling slash, cultivating rubber,slash-and-burn and cultivating sugarcane and sweet potato,etc., on main soil physical properties,such as soil temperature,soil water content,soil aggregate structure,soil mechanical composition,soil volume weight, porosity and water retention property,were analysed Results show that,over-felling of tropical secondary forest and the unreasonable slash-and-burn cultivation seriously influences,the main soil surface temperature and temperature differences,decrease soil water content and water retention ability,destroy soil structure,and lead to soil clay loss,soil sandification and so on,resulting in deterioration of soil ecological environment,directly influencing forest regeneration,forest land exploitation and utilization.Among them,the influences of slash-and-burn cultivation and clear felling slash are most serious.It is suggested that selective felling 50% and strip cropping of rubber would be the reasonable management and utilization ways if soil physical properties are only considered.