The content of phosphorus forms in calcareous irrigated serozems of the Tashkent region of Uzbekistan

Abstract

Abstract In most cases, the irrigated soils of Uzbekistan provide low forms of phosphorus assimilated by plants due to their high fixation. Therefore, the bioavailability of P is one of the main factors limiting the yield of crops. The study aimed to identify the transformation of phosphorus in irrigated gray soils under the influence of the type of land use, age of development, and climate (location above sea level). For this purpose, the content of inorganic and organic pools of P was studied according to the Hedley method. The highest Pt values were noted in the soil of the Parkent region, where the amount of precipitation significantly exceeds that in other studied areas, as well as in the winterwheat-repeatedcrops-cotton (WW-RC-C) land use type with long-term use of high P fertilizer rates. In the studied soils, the share of Pi was 89-91%, while the share of Po was 9-11% of Pt. In the accumulation of labile P, in contrast to the accumulation of Pt, the greater availability of atmospheric precipitation and the WW-V type of land use, where the content of labile P. was significantly higher than in other studied soils. The obtained results indicate the need for individual consideration of the control of phosphorus nutrition of plants on soils used in various types of land use, their geographical location (altitude above sea level), and the age of development for agriculture, depending on the phosphate state of soils.