Journal of Environmental Biology

Vertical distribution of cationic micronutrients across landscape positions on Meghalayan plateau in the North-Eastern Region of India

P. Debroy^1,2*, R.K. Jena¹, P. Ray¹, S. Bandyopadhyay³, S. Padua⁴, S.K. Singh⁵ and S.K. Ray¹    

¹ICAR-National Bureau of Soil Survey and Land Use Planning, Regional Centre, Jorhat-785 004, India

²ICAR-Indian Institute of Water Management, Bhubaneswar-751 023, India

³ICAR-National Bureau of Soil Survey and Land Use Planning, Regional Centre, Kolkata-700 091, India

⁴ICAR-Central Marine Fisheries Research Institute, Kochi- 682 018, India

⁵ICAR-National Bureau of Soil Survey and Land Use Planning, Nagpur-440 033, India

*Corresponding Author Email : partha.slg09@gmail.com

Paper received: 25.03.2019 ?????? ???????????????????????????????????????Revised received: 29.11.2019 ??????????????????????????????????? Accepted: 20.02.2020

Abstract

Aim: The study aims to get insight about the depth wise distribution of fractions of cationic micronutrients (Fe, Mn, Zn and Cu) and their availability across various landscape positions in an elevational gradient of Meghalaya.

Methodology: Soils were collected from four different soil depth viz. 0-15, 15-30, 30-45 and 45-60 cm representing major landscape positions, i.e., plateau top, side slope, foot slope and valley in a catenary sequence in the Umsning block of Ri-bhoi district, Meghalaya.     

Results: Cationic micronutrients and their fractions varied with soil depth and landscape positions in the study area. DTPA extractable Fe, Mn, Zn and Cu content was higher in surface layer as compared to the sub surface and found in higher amount in valley as compared to the other landscape positions. Zinc is the most limiting cationic micronutrient found in the study area, whereas poor availability of Mn was also observed in few sub-surface samples. Residual fraction was the largest fraction of cationic micronutrients in soil and varied from 58.4 to 71.0, 33.8 to 64.9, 66.0 to 84.1 and 30.1 to 65.6% of total Fe, Mn, Zn and Cu, respectively in the study area. Soluble and exchangeable fraction is the most labile pool of cationic micronutrients in the study area though its content was less. Organically complexed fraction contributed in large to the availability of Fe, Zn and Cu. Whereas, amorphous and crystalline Fe oxide occluded fractions of Zn and Cu and crystalline oxide occluded fractions of Mn were also found to contribute the availability of respective cationic micronutrients as an indirect source.      

Interpretation: Landscape position influences the distribution and availability of cationic micronutrients and their fractions in undulating terrain of Meghalaya through the distribution of clay, organic carbon and water content in soil profile. Moreover, present land use further modifies the availability of cationic micronutrients in the study area.       

Key words: Catenary sequence, Depth-wise distribution, Meghalaya, Micronutrient fraction

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