南海诸岛土壤的形成和年龄  

FORMATION OF THE SOILS IN THE SOUTH CHINA SEA ISLANDS AND THEIR AGES

作　　者：龚子同[1] 刘良梧[1] 周瑞荣[1] 

机构地区：[1]中国科学院南京土壤研究所

出　　处：《第四纪研究》1996年第1期88-95,共8页Quaternary Sciences

基　　金：国家自然科学基金;南沙综合考察资助

摘　　要：本文在阐明南海珊瑚诸岛土壤的生物集聚过程、积盐和脱盐过程，以及有关的土壤诊断特性基础上，进一步介绍了那里的磷质石灰土和滨海盐土两大土壤类型，它们的空间分布及其与岛屿结构、地形、植被和鸟类活动之间的关系。最后，作者针对南海珊瑚岛土壤的特征，运用（１４）Ｃ方法探讨了它的年龄及其与土壤形成、发育之间的相互关系。Islands in the South China Sea consist of Dongsha, Xisha, Zhongsha and Nansha Archipelagoes, including 260 small islands, of which the biggest ones are Yongxing island with 1.85 km2 and Taiping island with 0.43 km2. Many cultural relics unearthed in the islands and official written documents in the history have convincingly demonstrated that the islands had already been a part of China since the Qin and Han Dynasties (B .C.221-AD.220 ).The formation processes of the soils in the South China Sea Islands are apparently different from allitization of the tropical and subtropical soils in China.The islands soils are characterized by Ca-enriched parent materials, special biolgoical activities and salinization- desaliinization etc.1. Lithological characteristics and Ca-enrichment parent materials The soil parent materials of the South China Sea islands are mainly loose fragmentary sands of corals and shells with 95% of carbonate. Under the tropical oceanic climate, calcium carbonate affected by humic acids and abundant rainfall moves down from soil surfaces. Due to coral contribution, soil mass still contains high carbonate (62%-83%). In addition, the soils are light loam to loose sand in texture and remain lithological characteristics of obvious rock-like coral and shell fragments.2. p-enriched property and accumulation of phosphorous Diverse biological activities, especially sea birds leave large amount of guano to soils. Under humid and thermal conditions, the guano is quickly decomposed and forms phosphate. Then the phosphate moves downward and combines with Ca derived from corals and shells, finally resulting in p-enrichment property of soils with 7%-22% of P2O5.3. Accumulation of organic matter and isohumic property A great deal of organic matter accumulates on soil surfaces through decayed leaves and then increases soil organic matter content to a certain degree. This enhances further eluviation to deeper part of soil profiles, thus forming organic epipedon with dark brown color and organic subsurface horizon wi

关 键 词：南海 诸岛 磷质石灰土 土壤 年龄 碳14 

分 类 号：S151[农业科学—土壤学] S151.24[农业科学—农业基础科学]