Influence of prolonged agrogenic transformation on soil structure and physicochemical properties of Ukrainian Albic Stagnic Luvisols: a case study from western Ukraine

Albic Luvisol occupy large areas in Ukraine, have low natural fertility and high acidity. Effective use of such soils is possible in the agricultural system only after improving their fertility. This involves constant management of reclamation and technological measures in accordance with the longterm dynamics of soil processes. A long-term experiment was started in 1965 with different rates and ratios of mineral, and organic fertilizers as well as lime. The purpose of the study is to establish the influence of systematic application of different fertilization schemes and periodic liming on the change in the structural-aggregate composition and physico-chemical properties of Albic Stagnic Luvisol under different crop rotations. Studies have shown that the long-term use of different fertilization systems and periodic liming on Albic Stagnic Luvisol both in the 4th and 9th crop rotation caused a significant predominance of very fine (VF - 0.25-1.0 mm) soil aggregates over coarse ones (CO - 5-10 mm). Under the combined organo-mineral system of fertilization and periodic liming of 1.0 n CaCO3 (according to hydrolytic acidity), at the end of the 9th crop rotation, the content of large components is almost eight times higher than the content of very fine and medium ones (VM - 0.25-3.0 mm). The content 0.25-1.0 mm fraction along the profile increases significantly with increasing of depth in the control (without fertilizers) and with only mineral fertilization. This indicates deterioration of the waterproofing of the soil profile. Research results showed that the transformation of forest ecosystems into agricultural ecosystems improved the acid-base properties of Albic Stagnic Luvisol. The reaction of the soil became slightly acidic (pH 5.18-5.51) with the average multi-year application of a single norm of mineral fertilizers (N65P68K68), the norm of 10 t ha(-1) of cow manure against the background of the norm of 1.0 n CaCO3 pH(KCl). Hydrolytic acidity, beside the control, ranges from low to medium with maximum values in the middle part of the soil profile. We investigated the accumulation of humus only in the upper layers of the soil in the control and on various fertilization systems. The lower horizons contain less than 1% humus.