中文摘要：

选取桂林典型石灰土不同发育阶段土样（黑色石灰土、棕色石灰土、黄色石灰土）,对土壤中腐殖质组成、土壤钙的形态及其含量进行测定。结果显示：（1）石灰土发育过程中,黑色石灰土、棕色石灰土、黄色石灰土总碳量分别为230.15mg/g、37.49mg/g、17.94mg/g,胡敏酸所占比例分别为31.94%、9.44%、7.25%,富啡酸所占比例为1.04%、36.14%、66.16%,胡敏素为67.02%、54.41%、26.59%;（2）黑色石灰土、棕色石灰土、黄色石灰土中土壤钙全量分别为21 486.66mg/kg、6 913.33mg/kg、5 540.17mg/kg,且三种土壤中均是酸溶态所占比例最高,分别为57.58%、74.69%、80.83%,其次为可还原态、残渣态和可氧化态;（3）相关性分析表明,土壤钙及其各形态均与土壤有机碳总量、胡敏酸、胡敏素成正相关关系,与富啡酸成负相关关系,土壤腐殖质组成及其含量在很大程度上影响着土壤钙含量及赋存形态。

英文摘要：

Selecting the limestone soil samples at different developing stages（black limestone soil,brown limestone soil and yellow limestone soil）,the form and contents of the humus and calcium have been measured,the results show that：（1） at different developing stages of the limestone soil,the total carbon in the humus of black limestone soil,brown limestone soil and yellow limestone soil is 230.15 mg/g,37.49 mg/g and 17.94 mg/g respectively,the proportion of humic acid is 31.94 %、9.44 % and 7.25 % respectively,fulvic acid accounts for 1.04 %,36.14 % and 66.16 %,and humin is 67.02 %,54.41 % and 26.59 % respectively;（2） the total calcium of the black limestone soil,brown limestone soil and yellow limestone soil is 21 486.66 mg/kg,6 913.33 mg/kg and 5 540.17 mg/kg respectively,the acid-soluble calcium has the highest proportion,with the proportion of 57.58 %,74.69 % and 80.83 %,followed by the reduced calcium,oxidized calcium and residual calcium;（3）the correlation analysis shows that the soil calcium and the different forms are positively related with SOC,humic acid and humin,negatively related with fluvic acid.It means that the forms and components of the humus can influence the form and components of the soil calcium to a large extent.