Quantitative analysis of the clay seperate of soils

Quantitative analysis of soil elay minerals after X-ray, differential thermal, infrared, cation exchange and chemica! analysis is treated. Partiele size, crystallite size, the grade of structural ordening in the minerals, and the surface being covered by an amorphous (Beilby) layer, have large influence on the results. Examples are given

Bijdrage tot de kennis van de kationen- en anionen-adsorptie van tropische en Nederlandsche gronden

When percolating a soil with neutral or weakly alkaline normal solutions (pH about 8.3) of different acetates, the order of cation adsorption, Mg>Ca>Ba>Na, follows that of solubility of the hydroxides. However cation adsorption for NH 4 , K, Ba and Na when percolating thereafter with the chloride solutions are alike.The above constant cation value (in m-equiv./100 g) does not change with repeated exchanges neither does it change when acid or alkaline solutions are used such as 0.05 N HCl, 0.5 N FeCl 3 , 0.5 N AICI 3 , about 0.2 N Ba(OH) 2 . Tropical soils may contain much material inactive or hardly active in cation exchange (quartz, iron-, aluminium hydroxides, silicic acid and kaolinite) which disturb the relation between total surface (particles After treating soil with HCl sp.gr. 1.035 for 0.5 h at 55°C, cation value decreases slightly but still remains proportional to the surface of the soil particles. The amount of silica in excess of (or less than) the amount of Fe 2 O 3 + Al 2 O 3 (in m- equiv.) dissolved by HQ sp.gr. 1.035 for 1 h at 55°C and the SiO 2 /Fe 2 O 3 + Al 2 O 3 ) quotient are correlated with the amount of PO4 3-which is fixed from Ca (H 2 P0 4 ) 2 solution. The amount fixed depends also on temperature, duration of the reaction and concentration of the components (soil and Ca (H 2 PO 4 ) 2 solution). Cl -and SO 42-are bound to the soil as iron and aluminium hydroxide compounds which, however, are easily hydrolyzed

Über die amorphen Stoffe in den Tonen verschiedener Böden

In der Feinfraktion des Bodens findet man die amorphen organischen Stoffe, die hauptsächlich aus Huminsäuren bestehen. W. Flaig und H. Beutelspacher (1950, 1951, 1954) konnten zeigen, daB sie im Elektronenmikroskop als kugelförmige Teilchen zu sehen sind