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Subject: Soil Science × Author: Bhat, Mohammad Amin × End date: 2019 × Start date: 2010 ×
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    ThesisItemOpen Access
    Kinetics of potassium release and its response to maize and oats in major soil orders of Haryana
    (CCSHAU, 2019) Bhat, Mohammad Amin; Grewal, K.S.
    The data on physico-chemical properties of the soil samples reveal that the soils were alkaline in reaction, non-saline, non-calcareous, sand to sandy clay loam in texture and having low to medium organic carbon and available P and low available N. The variation in soil properties reflects the diverse parent materials. The kinetics of non-exchangeable potassium release from whole soil and different soil fractions collected from major soil orders of Haryana was investigated using nitric, citric and oxalic acids. Calcium saturated soils and soil separates were equilibrated for 0.25 to 100 hr. The release of K increased as a function of time. Almost more than half of the potassium was released in first five hours of equilibration thereafter the release plateaued. The maximum K release was observed in clay fraction followed by whole soils, silt, fine sand and minimum in coarse sand at all the three concentrations of the acids concerned. Highest amount of K was released from the soils and soil separates using oxalic acid followed by nitric acid and lowest by citric acid. By and large, the release of non-exchangeable K was maximum in Alfisols followed by Inceptisols, Aridisols and least in Entisols.The kinetics of potassium release was evaluated using zero order, first order, Elovich, parabolic and power functions. In general, Elovich equation and power function equation best described the potassium release from soil and its fractions as evidenced by higher values of coefficient of determination (R2) and lowest value of standard error (SE) of estimate. Water soluble accounted for 0.06 percent, available K accounted for 0.56 percent, exchangeable K constituted 0.51 percent and non exchangeable K constituted about 3.21 percent of total K. More than 94 percent of the total K was in mineral form suggesting that parent material is the origin of most of the K. The positive and significant correlations amongst the forms of K are indicative of the existence of interdependency and dynamic equilibrium between K forms. Positive and significant correlation between non-exchangeable K and clay (r =0.80; p ≤ 0.05) and silt fraction (r =0.95; p ≤ 0.01) suggest that finer fractions would supply K when soil solution and exchangeable K are depleted. The potassium releasing power of various soils was assessed in screen house by growing maize and oats in succession. As far as total K uptake by crops is concerned, available K contributed 33.59 per cent whereas contribution from non-exchangeable sources was nearly 66.41 per cent to total K uptake. Better correlation coefficients between cumulative K uptake and non-exchangeable K release to oxalic acid can be used to predict and ascertain the long term K supplying power of the soils. The constants ‗a‘ and‗b‘ calculated from Elovich equation were significantly correlated with available K and cumulative yield. However, both the constants showed positive correlation with cumulative but non significant.