Resulting from lower of clay fraction content, organic mater content, CEC, Exchangeable cations, all of Hanoi agricultural soils samples have smaller liquid limit, plastic limit, plastic index and activity than those of Japanese agricultural soils. | BÀI BÁO KHOA H C CHARACTERIZATION OF CLAY MINERALOGICAL COMPOSITION AND CONSISTENCY OF HANOI AGRICULTURAL SOILS – COMPARISON WITH JAPANESE AGRICULTURAL SOILS Nguyen Thi Lan Huong1 Abstract: Five agricultural soil samples from Hanoi, Vietnam were subject to clay mineralogical analysis and determination of the soil plasticity in addition to measurement of pH, organic matter content, cation exchange capacity (CEC) and exchangeable cations and particle size distribution. The pH, CEC and exchangeable cation of soil samples were similarly. In contrast, organic matter content and clay particle were comparable between the soils samples. The predominant clay minerals in soil samples were mica and kaolinite. In addition, to compare the plastic number, six Japanese agricultural soil samples were picked up. Resulting from lower of clay fraction content, organic mater content, CEC, Exchangeable cations, all of Hanoi agricultural soils samples have smaller liquid limit, plastic limit, plastic index and activity than those of Japanese agricultural soils. Keywords: Clay mineralogical, plastic number, agricultural soil. 1. INTRODUCTION1 It have been well-know that clay mineral it plays an importance role in determining soil fundamental physical and chemical properties and soil potential fertility, event through, it represents the smallest mineral substance in the soils. Especially, it takes an active part in the adsorptive process and nutrient exchange (cations and anions) with soil solutions. Therefore, clay content and mineralogical composition of soils to increase their fertility or productivities should be paid attention. Hanoi is the capital of Vietnam which is located in the deltaic plain of Red river in Northern Vietnam. Naturally, as a sedimentary process, the soil deposits in the City have been influenced by the Red River. The geological status of Hanoi City is described as being composed of Neogene system and Quaternary system (Yamadera and Suzuki, 2004). The Quaternary
