Vol. 9, Issue 5 (2020)

Author(s):
Bidisha Borpatragohain, Dwipendra Thakuria, Ashish Rai, Bharati Upadhaya and Subhra Sahoo

Abstract:
A laboratory experiment was conducted in the College of Post Graduate Studies in Agricultural Sciences, Umiam, Meghalaya. The surface soil samples of 3 soil profiles were used in the study representing the soil order Entisol. 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 Entisol comprised of 3 profiles viz., P1, P2 and P3 representing Changlang (Arunachal Pradesh), North-West-1 Jorhat (Assam) and North-West-2 Jorhat (Assam), 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 103 to 577 for the soil profiles of Entisol. The maximum PFC was obtained at the P application dose (µg g^-1 soil) for North-West-1 Jorhat (Assam) at 200. The higher percent P fixed was in order of Changlang, Arunachal Pradesh (68.2) > North-West-1 Jorhat, Assam (46.2)> North-West-2 Jorhat, Assam (33.3). The bulk density (BD), maximum water holding capacity (MWHC) and clay content ranged from 1.02 to 1.18 g cc^-1, 33.6 to 55.5% and 3.7 to 10%, respectively among the 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 0.5 to 1.2%, 122 to 226 kg ha^-1, 20.8 to 24.6 kg ha^-1 and 115 to 126 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 5.8 to 7.7, 0.09 to 0.28 meq 100 g^-1 soil, 18.4 to 22.6 mg kg^-1 soil, 6.8 to 12.9 meq 100 g^-1 soil, 44.4 to 71.0%, respectively. The soils of Changlang, Arunachal Pradesh showed the highest percentage of P fixation and North-West-2 Jorhat (Assam), the least among the profiles. Thus, higher phosphatic fertilizers have to be applied for Changlang district of Arunachal Pradesh to render P available for plant uptake as compared to the other profiles. Furthermore, appropriate adaptive management practices should be designed to alleviate P losses and thereby, increase the percentage of phosphorus use efficiency.