白浆土、黑土、草甸土土壤颗粒组成及微团聚体比较研究

用吸管法测定白浆土、黑土和草甸土的土壤颗粒组成和微团聚体,结果是白浆土普遍存在有粘化层,粘粒的淋淀指数为1.32—3.86,以典型白浆土粘化较重,淋淀指数达2.95～3.86;草甸白浆土和潜育白浆土淋淀指数为1.32—2.55。草甸土和黑土一般无粘化层。粉粒的淋淀指数,白浆土较小,说明粉粒在白浆层中有积累。土壤中的微团聚体组成变化比较复杂,三种土壤之间无一定规律。总的说来,因受腐殖质的影响,三种土壤表层分散系数较低,一般均小于10％;白浆土的分散系数较大,下部土层达20—37％,说明白浆土的母质有较大的分散性。有些黑土和草甸土分散系数虽大,但粘粒没有发生悬浮迁移,这可能与土壤渗透性弱有关。

COMPARED STUDY ON SOIL PARTICLE CONSTITUENT AND MICROAGGREGATE OF ALBISOL, BLACK SOIL AND MEADOW SOIL

The soil particle constituent and microaggregate of albisol, black soil and meadow soil were determined by means of pipette method. The results showed that the albisol has a Bt horizon in universal. The index of eluviation and illuviation of clay (<0.001mm ) of albisol is 1.32-3. 86, the argilluviation of the typical albisol is greater and the index of eluviation and illuviation is 2.95-3.86, and the index of meadow albisol and gley albisol is about 1.32-2.55. There is not any Bt horizon in black soil and meadow soil. The index of eluviation and illuviation of the silt in albisol is less. It indicates that there is silt accumulation in albic horizon. The variations of microaggregate in the three soils are more complicated. There is not any fixed pattern among them. Their coefficient of dispersion is lower(<10%) in humic horizon because of the influence of the humus. The coefficient of dispersion of albisol is higher (20-37) than others. It indicates that the dispersity of parent material of albisol is greater than that of its top horizons. Although some black soil and meandow soil have high dispersed coefficient, yet their clay illuviation don't accurred, that maybe is caused by the weak percolation ratio.