EFFECT OF DRAINAGE ON THE STATUS AND FABRIC OF CONCRETIONS IN GRAY FOREST GLEYED SOILS

The water regime determines the development of hydromorphic features i n soils as well as morphological and chemical properties of concretion s found in them. By the example of light gray gleyed soils, it was est ablished that with the increase of gleying (in the sequence from deepl y gleyed to slightly gleyed soils), the content of large concretions ( >3 mm in diameter), mobile Fe, and the begging index (the ratio of Fe to Mn 1 N H2SO4 in extraction) increased by 6 to 8, 1.7 to 2.7, and 2 to 3 times, respectively. The first eight years of the aftereffect of drainage with ceramic and plastic drains were characterized by changes in morphology, total mass (by 2 to 2.3 times), and fractional and che mical composition of ortsteins. Drained soils had a tendency toward a decrease in absolute values of the bogging index.