The irrigated soils of Uzbekistan are calcareous and are characterized by low efficiency (15–20%) of applied phosphorus (P) due to their high fixation in the soil. Therefore, assessing various forms of P in these soils is of great importance for increasing the efficiency of using phosphorus fertilizers in agriculture. In this work, the P state of meadow-alluvial soils in the Tashkent region was studied. Phosphorus fractionation in soils was carried out using a modified Hadley sequential extraction method. The results obtained were subjected to standard methods of statistical processing. The research results showed that total phosphorus (Pt) content in arable soil horizons varies from 2359 to 2484 mg/kg. In this case, the share of inorganic phosphorus (Pi) is 89.94–91.56 percent, and organic phosphorus (Po) is 8.44–10.5 percent. The main part of soil P consists of stable P fractions with a multi-year renewal cycle. Thus, the content of calcium-bound Pi (1 m HCl−Pi) is 228–288 mg/kg, recalcitrant Pi (conc. HCl−Pi) is 62–90 mg/kg, and residual P (H2SO4 /H2O2) is 1730–1830 mg/kg. The content of labile Pi (H2O − Pi + NaHCO3 − Pi) was 32–46.5 mg/kg, and moderately labile Pi (NaOH−Pi) was 22–31 mg/kg. The Po content in labile and stable phosphorus fractions, available to plants after mineralization, deserves special attention. Thus, the content of rebellious Po (conc. HCl-Po) was 108–130 mg/kg, significantly exceeding the Pi content in this fraction. The same picture is observed in the Po content in labile and moderately labile fractions. The Po content in the labile P fraction (NaHCO3− Po) was 24–34 mg/kg in the moderately labile fraction (NaOH−Po) 65–86 mg/kg, significantly exceeding the Pi content in these fractions. Thus, when developing a phosphorus management strategy on irrigated meadow-alluvial soils to increase phosphorus efficiency, it is necessary to consider the content of phosphorus fractions in soils, paying special attention to the Po content in labile fractions.