Assessment of soil resources of agricultural landscapes in Turkestan region of the Republic of Kazakhstan based on agrochemical indexes

Natural and climatic features of the soil cover formation of Turkestan region of the Republic of Kazakhstan are identified by a set of hydrological and bioclimatic factors serving as important environment-forming functions, which are reflected in the landscape organization of the territory. When assessing soil resources of agricultural landscapes, integrated index of soil fertility was applied – the “soil index,” which takes into account the reserves of humus, mineral elements, and hydrolytic acidity. Based on monitoring observations (1996–2019) of soil fertility in agricultural landscapes (agricultural lands) of Turkestan region, assessment of soil resources was performed, which showed that in general, the generalized “soil index” ranges from 1.086 to 4.800 units depending on natural features of the territory. It is found that the “soil index” in agricultural landscapes is significantly less than its maximum value (20.000 units), which suggests a pronounced humus deficiency, showing low soil fertility in all agricultural landscapes. To assess the soil resources of agricultural landscapes in Turkestan region, a new approach was applied, which is based on the assessment of energy costs for the soil formation process, which enables to quantitatively reflect the radiation balance of the earth surface, heat, and moisture supply of agricultural land for 1941–1960 and 2001–2020. The indicators applied are subject to the law of vertical zonation and change from the mountain to the arid zone, where the potential energy costs for soil formation range from 82.2–101.9 to 129.4–135.5 kJ/cm2, and natural energy costs energy costs for soil formation from 17.2–21.7 to 121.7–125.2 kJ/cm2.