Study of phosphorus fixation capacity in Alfisol soil order of North-East India

Abstract

The surface soil samples of 3 soil profiles were used in the study representing one of the dominant soil order of North-East India i.e. Alfisol. The physical and chemical attributes of the 3 profile soils along with the ability of the profiles to fix phosphorus (P) were determined in this investigation. The order Alfisol comprised of 3 profiles viz., P1, P2 and P3 representing Changlang (Arunachal Pradesh), Sepahijala (Tripura) and Ri-Bhoi (Meghalaya), respectively. Results from the incubation experiment (P levels 0, 25, 50, 100, 200, 300,400, 500, 600 and 700 ppm for 24 h) indicated that phosphorus fixation capacity (PFC) (µg P g-1 soil) ranged from 223 to 471 for the soil profiles of Alfisol. The maximum PFC was obtained at the P application dose (µg g-1 soil) for Changlang (Arunachal Pradesh) at 500.The higher percent P fixed was in order of Ri-Bhoi, Meghalaya(94.1) > Sepahijala, Tripura (85.1) > Changlang, Arunachal Pradesh (74.4). The bulk density (BD), maximum water holding capacity (MWHC) and clay content ranged from 0.91 to 1.00 g cc-1, 32.7 to 51.8% and 15 to 40%, respectively among three soil profiles. The content of soil organic carbon (SOC), soil available nitrogen, phosphorus and potassium (Avl.N, Avl.P and Avl.K, respectively) ranged from 1.4 to 1.8%, 270 to 301 kg ha-1, 9.7 to 22.8 kg ha-1and 155 to 220 kg ha-1, respectively. Soil pH, exchangeable aluminium (Ex.Al), readily soluble aluminium (RS.Al), exchangeable calcium+magnesium (Ex.Ca+Mg) and base saturation (BS) ranged from 4.4 to 6.3, 0.12 to 3.59 meq 100-1g soil, 18.8 to 354 mg kg-1 soil, 2.8 to 8.1 meq 100-1g soil, 39.9 to 55.3%, respectively. The soils of Ri-Bhoi, Meghalaya showed the highest percentage of P fixation and Changlang, Arunachal Pradesh the least among the three profiles. In order to minimize the loss of phosphatic fertilizers, site-specific nutrient management is suitable and formulation of appropriate fertilizer dose should be undertaken to achieve maximum phosphorus use efficiency from these locations.