Evaluation of Chemical Extraction Methods for Determining Plant-Available Potassium in Some Soils of West Bengal,India |
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| Authors: | Suranjit Sarkar Sanmay Kumar Patra |
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| Institution: | 1. Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India;2. Chief Scientist, AICRP on Irrigation Water Management, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India |
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| Abstract: | The effectiveness of eight chemical extraction methods was evaluated on 15 Indian soils for the prediction of plant-available potassium (K+) to Sudan grass (Sorghum vulgare var. sudanensis) grown in modified Neubauer technique. Average amounts of soil K+ extracted were in descending order: Morgan’s reagent > 0.5 M sodium bicarbonate (NaHCO3) > neutral 1N ammonium acetate (NH4OAc) > 1N nitric acid (HNO3) > 0.02 M calcium chloride (CaCl2) > 0.1N HNO3 > Bray and Kurtz No.1> distilled water. The highest simple correlation with plant K+ uptake was obtained with NH4OAc-K+ (r = 0.866**) and the lowest with CaCl2-K+ (r = 0.45*). To develop the predictive models using stepwise regression, plant K+ uptake was used as the dependent variable and the extractable soil K+, pH, sand, silt and organic carbon (C) contents as the independent variables. Based on the final R2, the NH4OAc model was found to be the best predictor of plant-available K+ in the soils when used along with sand and organic C. |
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| Keywords: | Extractant Indian soils plant-available K+ prediction models Sudan grass |
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