Vol. 9, Issue 10, Part G (2025)

Phosphorus dynamics in soil is a complex process, influenced by cultivation practices and land-use patterns. The knowledge regarding the forms of phosphorus, and conditions controlling their availability is of importance in the appraisal of their status in soil. Phosphorus fractions in soil profile samples of various land use systems in northern transect of Bengaluru were studied in relation to soil properties. The results indicated that soil texture of the surface horizons was varying from sandy clay to sandy clay loam while for subsurface horizons it varied from sandy clay to clayey in soil profiles of different land uses. The soil pH varied from moderately acidic to slightly acidic in surface horizons and moderately acidic to slightly alkaline in subsurface horizons. Soils were non saline in nature under different land uses and EC followed increasing trend with soil depth in all profiles. OC decreased with soil depth in all the soil profiles with higher values recorded in surface horizons of forest (20.10 and 21.70 g kg^-1 in profile 5 and 6, respectively) and organic farming (13.10 and 12.40 g kg^-1 in profile 9 and 10, respectively) land uses. Saloid P, Al-P and Fe-P contents decreased with increasing soil depth in soil profiles of different land uses with higher values recorded in surface horizons of agriculture (15.37, 121.63 and 145.83 mg kg^-1, respectively) and horticulture land uses (16.78, 146.25 and 157.02 mg kg^-1, respectively). Reductant soluble P was recorded higher in surface horizons of forest (112.29 mg kg^-1) and horticulture (102.61 mg kg^-1) land uses. Organic-P was recorded higher in soil profiles of forest (93.65 to 265.11 mg kg^-1) and organic farming (72.35 to 220.89 mg kg^-1) land uses while lowest values of organic P were recorded in fallow land use (27.19 to 80.25 mg kg^-1). Total-P ranged from 173.17 to 628.59 mg kg^-1, 161.26 to 717.68 mg kg^-1, 152.83 to 376.42 mg kg^-1, 199.27 to 569.83 mg kg^-1, 186.46 to 482.42 mg kg^-1and 76.52 to 221.77 mg kg^-1 in different horizons of soil profiles of agriculture, horticulture, sericulture, forest, organic farming and fallow land uses, respectively.