CHANGES IN THE MORPHOLOGICAL AND AGROCHEMICAL PROPERTIES OF THE DARK SEROZEMS OF THE CHATKAL RIDGE
The subject of the study is virgin, irrigated dark serozem their properties. The paper shows that the soil-forming rocks, on which dark sierozems are formed, are represented by stony proluvial and deluvial sediments. The virgin dark serozems are clearly distinguished by the soddy horizons, which have a thickness of 7-10 cm. In the virgin serozem at a depth of 17-73 cm, the carbonate-illuvial horizon is distinguished. In this horizon, caprolites, lime nodules, mold of carbonates are observed. A characteristic feature of dark serozem is the increased humus content of the sod horizon of the order of 4 % and its sharp decrease in the underlying horizons. Dark gray soils are formed in conditions of moisture deficiency, which creates a separate course and direction of the soil-forming process. Irrigation leads to a decrease in the content of humus, nitrogen, an increase in the total phosphorus due to the introduction of phosphate fertilizers in the order of 150-175 kg / ha. Changes in the content of humus, carbonates affect the composition and amount of absorbed bases. In virgin soils, the content of absorbed calcium varies within 81.6-86.9 % of the amount. In irrigated soils, the same indicator is in the range of 69.6-82.3 %. These changes occurred almost due to absorbed magnesium, whose share in irrigated soils compared to virgin soils increases about 1.6-2.9 times. In general, a decrease in the content of humus, absorbed calcium and the growth of magnesium in irrigated soils leads to a decrease in the potential fertility of dark serozems.