摘要
在偏碱富钙的岩溶生态系统中,其土壤具以下特征:①形成速率十分缓慢,形成1m厚的土层需要250～7880ka,因而对岩溶区土壤侵蚀的评价应有新的认识;②高含量的钙离子使土壤腐殖质中胡敏酸的含量比例较高,且稳定性好,不易分解的腐殖质使石灰土供应营养元素具缓效性;③微量营养元素含量及有效态具有不平衡性,且随钙镁含量的降低,其有效率显著提高;④粘粒含量高,当有机质含量高时,具有良好的团粒结构,有较好的供水、供肥能力,反之其团粒结构就失去稳定性,使土壤有效水含量、抵御水土流失的能力降低;⑤岩溶地貌制约石灰土的类型及分布,并延缓其向地带性土壤演化。因此石灰土资源的有效利用应从岩溶学、土壤学与植物学相互协调的角度进行生态经济规划。
Many features of limestone soil are controlled by the carbonate rock with rich calcium:①the rate of limestone soil formation is very slow, and the formation of 1m thickness soil last 0.25～7.88 million years. However, the rate of soil erosion in karst area is from several decade to hundred times than that of the soil formation. Therefore, the damage of the soil erosion is more serious than we think;②the high concentration and good immobility of soil humus closely related with the high concentration and activity of calcium in soil, mainly, the humin acid could be combined with the calcium in the soil to form stable humin calcium, however, the nutrient elements are slowly provided for vegetation; ③ the content and validity of trace elements in limestone soil are unstable, the validity of trace elements would become more effective as the concentration of calcium and magnesium decreasing. By the way, the behavior of zinc in limestone soil is in particularity,because of zinc in alkaline soil usually depositing;④ limestone soil has more clay component than other soils, because its parent material is carbonate rock which precipitated in clean sea environment. So when the soil in high humus, it might have good aggregate structure and effectively to support water and fertilizer for vegetation growing; by contraries, when the soil in low humus, its aggregate stability is weak and the available water for vegetation become short, therefore, the ability of the soil to resist soil erosion become low; ⑤ the limestone soil types and their distribution controlled by karst geomorphology, the black limestone soil usually scatters in the upper hillside with 10～30 cm thick, the brown and yellow limestone soils are covered the foot of the hill, depression and valley, and they usually are used to cultivated land, and the red limestone soil can be found in the peak forest plain area. During the limestone soil development and evolvement, the losing and taking calcium action are the key factors. In other word, the rich calcium in karst environment postpones the limestone soil to approach to zone soil. Therefore the effective landuse planning should be designed taking use of karstology, soil science and botanic nutrion.
出处
《地球科学进展》
CAS
CSCD
2003年第1期37-44,共8页
Advances in Earth Science
基金
国土资源部重点科技项目"中国西南岩溶生态系统研究"(编号:2000208)
科技部攀登计划特别资助项目"全球岩溶生态系统对比"(编号:200026)
国家自然科学基金项目"我国西南岩溶生态系统的运行规律及石漠化趋势"(编号:40152002)
广西自然科学基金(编号:20010229)资助.
