桂林毛村岩溶区和非岩溶区土壤有机质与氮分析研究

The Primary Analysis of Soil Organic Matter and Nitrogen in Karst and Non-karst Areas of Maocun,Guilin

用五点混合取样法采集广西桂林毛村岩溶区和非岩溶区典型林地、灌草丛地和耕地的0～20cm,20～40cm土壤样品,以高温外热重铬酸钾氧化—容量法测定有机质含量,半微量凯氏法测定全氮含量,碱解扩散法测定有效氮含量,电位法测定pH值。结果表明:岩溶区和非岩溶区的有机质,全氮和有效氮的含量都是表层明显高于底层;相同土地利用类型下,有机质、全氮和有效氮在0～20cm的含量是岩溶区高于非岩溶区,且林地>灌草丛地>耕地;有效氮含量与全氮和pH值有显著的正相关关系。

The samples are collected with composite sampling method in karst areas and non-karst areas in Maocun,Guilin of Guangxi. And they are collected between topsoil （0- 20cm） and subsoil （20-40cm） in forest soil,arable soil and grassland soil respectively. Soil organic matter, total nitrogen, available nitrogen and pH are measured with high temperature potassium dichromate oxidation-capacity,semiminim karl method ,alkaline hydrolysis pervasion method,and the potentionmeter method respectively. The results show that soil organic matter, total nitrogen and available nitrogen is more in topsoil than in subsoil,and that with.the same land-use,the content of soil organic matter,total nitrogen and available nitrogen between 0-20cm is more in karst areas than in non-karst areas,more in forest soil than in grassland soil,more in grassland soil than in arable soil. Available nitrogen and total nitrogen is significantly and positively correlated with pH.