Physical and chemical properties of bentonite and its influence on acid and alkaline indicators and fertility of sod-podsolic sandy loamy soil (retisols)

The article presents data on how bentonite clay (applied at reclamation rates) affects acid-alkaline characteristics and fertility indicators of soil (sod-podsolic sandy loamy soil - retisols). The experiment was conducted in the Nizhny Novgorod region. Physical and chemical properties of the used bentonite clay were preliminary studied. It is characterized by alkaline reaction of aqueous solution (pH 10.9) and of salt extract as well (pH 9.8) and undergoes electrolytic dissociation. The micro-plot field experiment which lasted over 3 years revealed some positive effect of bentonite application. As a result, the lowering of exchangeable soil acidity (by 0.31. рНKCl units) and hydrolytic soil acidity (by 0.20 mg-eqv./100 g) was recorded, substantial reduction of aluminium soluble forms content (up to 48 %) was noticed as well, meanwhile the content of exchangeable Ca2+ and Mg2+ increased by 0.70 and 0.24 mg-eqv./100 g correspondingly. Bentonite application contributed to humus preservation in the soil and humus content was maintained at 1...