利用湿筛法进行土壤团聚体分组(＞2、2～0.25、0.25～0.053、＜0.053 mm粒级),研究了其添加不同用量玉米秸秆,25℃恒温室内培养对团聚体中胡敏酸数量和结构特征的影响.结果表明:添加玉米秸秆培养后,土壤团聚体2～0.25 mm和＞2 mm粒级成为优势粒级,平均含量分别占51.41％和34.12％,其全碳含量为10.15～25.74 g kg-1,胡敏酸(HA)绝对含量为4.06 ～5.79 g kg-1,明显高于对照CK的9.79～10.48 g kg-1和3.70 g kg-1,并随玉米秸秆用量的增加而增大；各处理胡敏酸C/H及高温/中温比值均低于CK处理,并随玉米秸秆用量的增加逐渐减小,说明随玉米秸秆用量的增加使HA分子缩合度降低,结构趋于简单化.%Fractionation of a soil sample for soil aggregates of different size grades ( > 2 mm, 2 ~ 0. 25, 0. 25 -0. 053 and < 0. 053 mm) was carried out using the wet screening method for the study on effects of application of corn stalks on quantity and structural characteristics of humic acid in aggregates of the soil incubated indoors at a constant temperature of 25℃. Results show that after the application and incubation, aggregates of size fractions 2-0.25 mm and >2 mm turned out to be dominant in the soil accounting for 51. 41% and 34. 12% , respectively, on average. Their total carbon content ranged in 10. 15 ~25. 74 g kg-1, and their absolute HA content in 4. 06 ~5. 79 g kg-1, obviously higher than what was in the control, and the differences got bigger and bigger with the application rate of com stalks; However, the C/H and high/medium temperature exotherm ratios were lower in all the treatments than in the control, and negatively related to application rate of com stalk, which suggests that higher com stalk application rate makes HA molecules less condensed and simpler in structure.
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