Solubility Relationship of Metals in Acid Soils of Kumaon Himalaya Region of India

ABSTRACT

This study evaluated metal availability under acidic soil conditions and identified the solid phases that govern their solubility using Baker soil test. Free metal ion activity (Mⁿ⁺) expressed as negative logarithm value (pMⁿ⁺ = -log₁₀ Mⁿ⁺) of iron (pFe³⁺), manganese (pMn²⁺), copper (pCu²⁺), zinc (pZn²⁺), nickel (pNi²⁺), cadmium (pCd²⁺), and lead (pPb²⁺) ranged from 17.5 to 21.3, 5.2 to 8.4, 12.2 to 15.3, 9.3 to 11.9, 11.5 to 14.8, 11.8 to 15.1, and 10.9 to 13.4, respectively. The activities of Fe, Cu, Zn, Ni, Cd, and Pb in the soil solution are likely to be buffered by exchange reactions rather than precipitation-dissolution reactions. However, bixybite and manganite oxides are likely to govern the free Mn²⁺ activity in the soils. Based on intensity and quantity parameters, the soils were found to have sufficient supply power for plant essential elements (i.e. Fe, Mn, Cu, Zn, and Ni) except in the coarse-textured soils of Kosi. Nevertheless, the toxicity of iron in Someshwar and cadmium in Dhaili soils is expected under the prevailing soil conditions. The generated information on the solubility vis-à-vis availability of metals under acidic soil conditions will contribute to enlarge a field of research which is crucial for land management and deserves more attention, particularly in the fragile mountainous ecosystem.

KEYWORDS:

• Acid soil
• Baker soil test
• metals
• Free ion activity

Acknowledgments

The first author is grateful to the Ministry of Higher Education and Scientific Research, Syria for financial support. The first author is also thankful to the Head and Professor, Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute (IARI), New Delhi, India for providing the necessary facilities to carry out the research work.

Disclosure of potential conflicts of interest

All the authors display no financial or any other conflict of interest

Additional information

Funding

This work was supported by the Ministry of Higher Education and Scientific Research, Syria.