Long-lasting Effects of Bentonite on Properties of A Sandy Soil Deprived of the Humus Layer

Bentonite has been recognized as a very good material for the improvement of coarse textured soils. In microplot experiment, of a sandy soil deprived of the humus layer was enriched in 1973 with waste bentonite at the rates of 0, 3, 6 and 12 kg m -2 . Until 2002, the microplots were planted with different crops and regularly enriched with mineral and organic fertilizers. Since 2003, the microplots were left barren. In 2009, determinations of several features of the soils (in 5-30, 30-55 and 55-80 cm layers) showed that the historical amendment of the sandy soil with bentonite (especially its highest dose) ensured significantly higher contents of water, organic C, clay, silt and a sand fraction with particle diameter