DYNAMICS OF SALT COMPOSITION IN BARABA SOLONETZES EXPOSED TO GYPSUM EFFECT DURING 27-32 YEARS

Abstract

The most continuous and efficient way to improve solonetz fertility is chemical reclamation that creates conditions for proper development of crop plants. A single application of gypsum in the solonetzes of Novosibirsk region northern forest-steppe produces a continuous reclaiming effect. It is established that for the first two years after the ameliorator having been applied and due to exchange reactions proceeding in the 0-20 cm reclamation layer the content of salts largely rose up to 21-23 t/ha versus the control 3-5 t/ha. The salts were mostly represented by Ca, Mg, Na and sulfate ions. In the subsequent years, when exposed to atmospheric rainfalls and with comparatively stable level of mineralized ground water-tables, the salts were washed through to the lower horizons. From the year 1987 and further, the depth of ground water-tables varied from 240 to 265 cm and this influenced the direction of soil formation process: the degree of soil profile gleyzation went down. In the too wet year 2013, ground waters went up to the 50 cm depth and this intensified solonetz salinization in the gypsum applied option. Solonetz alkalinity increased, carbonates and bicarbonates content, particularly Na cations, rose. Ground waters pH value has been in the alkali interval since the year 1987.The highest value of the index involved was 8.5 in 2013. In the solonetzes with low Na content the salinization process ran more intensively than in those with high Na content. In the fall, ground water-tables went down to 200 cm and reclaimed solonetzes desalted again.