我国华南地区不同利用条件下土壤演变对障碍因子的影响

摘要

华南地区不同土壤利用条件下土壤性质演变和障碍因子的识别,对该地区土壤发生过程和管理利用有重要参考价值.本文根据中国土壤系统分类的检索原则,在收集华南9省土种志典型剖面资料的基础上,确定了系统分类的土壤类型,并基于此,研究了不同利用条件下,土壤性质的演变,分析了土壤障碍因子及其影响程度.总的来看,发育在林地条件下的土壤,粉粒、pH、阳离子交换量(CEC)、盐基饱和度(BS)、速效磷、速效钾都明显低于旱耕地土壤,有机质、全氮则相反.林地土壤随着风化作用增强,从雏形土、淋溶土、富铁土到铁铝土,土壤黏粒含量逐渐增加,而土壤pH、CEC、有效CEC(ECEC)、有机质、全氮、速效磷、速效钾等逐渐降低.对旱耕地而言,各种土壤性质基本具有与林地土壤性质一致的变化趋势,但是增加或减少的程度有所不同.结合主成分中土壤性质的组合特征来分析土壤障碍,结果表明华南地区土壤在不同土壤利用和类型下都存在养分贫瘠化、酸化、黏化、磷和钾供应能力低下的主要障碍因子,但各障碍因子发生的次序不同,随着风化作用加强,土壤黏化成为最主要的障碍因子.因此,在土壤利用和管理过程中应因土制宜,根据土壤类型来确定适当的改良措施.%The evolution of soil properties and identification of soil limitation factors under various soil use conditions in south China are important for the process of soil genesis and land use management. This paper determined soil classification with typical soil profiles in nine provinces in south China on the basis of Chinese soil taxonomy, evaluated the evolution of soil properties in terms of weathering intensity, and analyzed soil limitation factors influencing soil productivity. Generally, the soil properties such as silt content, pH, cation exchangeable capacity (CEC), base saturation (BS), available phosphorus and available potassium developed in forestlands were lower than those in dry farmlands, while organic matter and total nitrogen were opposite. With the strengthen of soil weathering, from Cambosols, Argosols, Ferrosols to Ferralosols, soil clay content was gradually increased, on the contrary, soil properties such as soil pH, CEC, effective CEC (ECEC), organic matter, total nitrogen, available phosphorus, and available potassium were gradually decreased. Although soil properties in dry farmlands had the same variation tendency as in those in forestlands, their variation were weak. The results of principal component analysis showed that the soil had main limitation factors as malnutrition, acidification, argillification, and low phosphorus and potassium availability for soil uses. The importance of the limitation factors was different in different soil uses and soil types and soil argillification became the most main limitation factor with soil weathering. So, establishment on suitable ameliorative measures would be based on the conditions of soil uses and types when the soils are used and managed.