FEATURES OF THE STRUCTURE OF THE SOIL COVER OF THE NORTHERN PART OF THE AKTAY-SHENTALA LANDSCAPE LOW - LYING AREA

Abstract

The results of the analysis of materials of a large-scale soil and agrochemical survey, morphological structure and properties of representatives of forest-steppe soils of the northern part of the Aktay-Shentalinsky landscape lowland region of the Republic of Tatarstan are shown. The territory is a poorly divided polygenetic plain with absolute heights of 140-150 m. The bedrock deposits have sandy-loamy layers of the Neogene and Pleistocene, overlain by cloaks of Quaternary deluvial loams, up to 20-21 m thick. The soil cover is dominated by leached medium–sized chernozems, which is 52.6% of the area, typical low–power and medium-sized chernozems - 39.6%, podzolized medium-sized chernozems - 2.7%, gray forest – 4.8%. The humus content in the agrogenic horizon of typical chernozems is average – 4.2-5.2%, and in leached chernozems ranges from 4.6% in a slightly washed analogue to 5.4% in full-profile representatives, where the humus content gradually decreases to the soil-forming rock. The potential reserves of humus of the studied subtypes of chernozems according to typical sections are in the range from 230 t/ha to 462 t/ha. According to the materials of the agrochemical survey for 1972-2021, the dynamics of the content of mobile forms of phosphorus in the arable horizon ranged from 103 mg/kg to 158 mg/kg. The weighted average amount of mobile potassium gradually decreased from 140 mg/kg to 101 mg/kg of soil. The actual yield of spring wheat and the dynamics of the content of mobile forms of potassium over the years of observation have a reliable correlation between each other. The obtained regression equations can be used to predict the yield of spring wheat in a given area. According to the results obtained, for each hectare of arable land for 51 years, about 149.9 kg of phosphorus was received with organic and mineral fertilizers, and since it is sedentary and difficult to dissolve, this led to its accumulation in the soils of the territory. The potassium balance is negative and amounted to -775.9 kg.