九宫山地带性土壤颗粒中粘粒矿物的特征

Characteristics of Clay Minerals in Particles of the Zonal Soils from the Jiugong Mountain

以湖北省九宫山的4种垂直地带性土壤(基带棕红壤、山地黄红壤、山地黄棕壤和山地草甸土)为材料,分离不同粒级的土壤颗粒(<2000 nm、450~2000 nm、100~450 nm和25~100 nm),并对各粒级颗粒的矿物组成进行分析,揭示山地土壤中粘粒矿物的演变特点。结果表明,随海拔升高,土壤中针铁矿、赤铁矿和高岭石减少,伊利石、1.42 nm矿物和三水铝石增加。随粒径减小,土壤颗粒中粘粒矿物组成和结晶状况发生明显变化,其中1.42 nm矿物、高岭石和伊利石减少,其结晶度变弱,而针铁矿和赤铁矿增多。土壤随山体海拔升高,三八面体矿物增加,二八面体矿物减少;而随颗粒粒径的减小,此变化规律反之。

Characteristics of clay minerals in various particle fractions( < 2000,450-2000,100-450 and 25-100 nm) of four vertical zonal soils( Base brown-red soil,Mountain yellow-red soil,Mountain yellow-brown soil,Mountain meadow soil) from Jiugong mountain in Hubei Province were investigated to reveal the evolution of clay minerals in mountain soils. Results indicate that the contents of goethite,hematite and kaolinite decrease but those of illite,14. 2  minerals and gibbsite increase in soils with increasing altitude. With reducing soil particles size,the changes of composition and crystallization of clay minerals are obvious,and the relative content of 14. 2  minerals,kaolinite and illite decrease but those of goethite and hematite increase. With the elevation of mountain,trioctahedral mineral increase while dioctahedral mineral decrease in soils. However,these changing rules are contrary to the reducing rules of soil particle sizes.