四湖地区不同水型水稻土的腐殖质分布特征

Distribution of Humus in Paddy Soils with Different Gleyed Degree in the Four Lake Regions of Jianghan Plain

在四湖地区采集了不同潜育程度 5个水稻土剖面共 2 0层样品 ,用傅积平改进法测定了样品的腐殖质组成 ,分析了松结态和稳结态中胡敏酸和富里酸的含量。结果表明 ,潜育度越高 ,表层土壤的有机质含量上升 ,土壤松结态、稳结态腐殖质中的胡敏酸、富里酸含量和紧结态腐殖质的含量也越高 ,紧结态腐殖质在重组有机质中的比例下降 ,而稳结态和松结态腐殖酸的比例增高。胡敏酸、富里酸和紧结态腐殖质的含量范围分别为0 .4～ 8.8、0 .5～ 10 .1、8.4～ 14 .6g/kg。松结态胡敏酸和富里酸含量均高于相应土壤中稳结态的含量。胡敏酸 /富里酸比值 (H/F)在松结态中为 0 .6 7～ 0 .98,稳结态中为 0 .85～ 1,重度潜育土、中度潜育水稻土和潴育型中比值增大 ,依次为 0 .73～ 0 .92、0 .89～ 0 .98和 0 .91～ 0 .

Five paddy soils with totally 20 layers samples were c ollected from the Four Lake Regions at the different gleyed degrees. The fractio ns of humus in the soils were measured through modified Fujiping's method. Resul ts indicated that the soil having higher greyed degree accumulated more organic matter under the different water conditions . Among all soils, the content of hu mus in tight knot morphic was the highest and that of steady knot morphic was th e lowest. However,the ratio of humus with tight knot morphic went down with the higher greyed degree in the tillage layer . The humic acid/fulvic acid ratio in loosely knot morphic was from 0.67 to 0.98 and in steady knot morphic from 0.85 to 1.00 .