Hastening Potassium Release from Mica Waste by Treating Humic Substrate Solution: An Approach to Adopt Mica Waste as Potassium Amendment in Tea-growing Soil

ABSTRACT

Muriate of potash (MoP) is generally applied in soil for supplementing potassium (K) in agricultural soil; though MoP has some disadvantages as K-fertilizer especially under humic agro-climatic condition. In this context, mica waste (MW) could be a potential alternative for K supplementing in soil. However, slow K-releasing nature limits its application as K source in agricultural soil. In this study, humic substrates (HS) were externally applied along with MW for hastening its rate of K release in soil. Application of HS and MW combination significantly (P < .05) increased K availability in soil. A pot study revealed that the combination of HS with even half of the recommended K in the form of MW sustained plant growth and recorded at par exchangeable K content in soil as compared to recommended MoP treatment. The scanning electron microscopy and x-ray diffraction revealed the changes in the crystal structure of HS-treated MW, and that might be attributed to the enhanced release of K from MW. Based on the observations, it could be concluded that application of HS at 7.5 kg HS ha⁻¹ hastened K release from MW to support the plant growth even after supplementing half of the recommended amount of K through MW. This controlled experiment established the potential of HS-treated MW as an alternative K source in agricultural soil. However, it also implied that a field experiment is necessary to optimize the combination of MW and MoP as an integrated K management treatment for a specific agroclimatic condition.

KEYWORDS:

• K supplement
• mica waste
• humic substrates
• tea-growing soil

Acknowledgments

The authors are thankful to the Director, Tocklai Tea Research Institute, Tea Research Association, Jorhat, Assam, India for his kind support and encouragement during this study. The work was supported by the funding of National Tea Research Foundation (NTRF), Tea Board of India (NTRF: 183/2016).

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Additional information

Funding

The work was supported by the funding of National Tea Research Foundation (NTRF), Tea Board of India [NTRF: 183/2016].