Effect of a fly ash and gypsum mixture on rice cultivation |
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| Authors: | Yong Bok Lee Ho Sung Ha Bum Ki Park Ju Sik Cho Pil Joo Kim |
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| Affiliation: | 1. Department of Agricultural Chemistry, Division of Applied Life Science, Graduate School , Gyeongsang National University , Chinju, 660-701, Korea;2. Product Development Team, Namhae Chemical Co. Ltd. , Yeosai, 550-701, Korea;3. School of Environmental and Agricultural Science , Sunchon National University , Sunchon, 315-540, Korea |
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| Abstract: | Abstract The salt titration (ST) method was evaluated as a method to determine ZPC in comparison with the potentiometric titration (PT) method for 26 soils with variable charge clays, i.e., Oxisols and Ultisols from Thailand and Andisols from Japan. In addition to the determination of ST-pH0 as the zero point of charge, a calculation procedure (STPT method) was adopted here in order to acquire more information from the titration curve. Furthermore, for the purpose of cross-checking of ZPC determined by the PT method, the ST procedure was successively applied to the samples analyzed by the PT method (PTST method). The soil to solution ratios of 1: 10 to 1: 5 gave almost an identical ST-pH0 value for every soil. The values of both ST-pH0 and PT-ZPC ranged from 4.7 to 6.3 for the Andisols, while for the Oxisols and Ultisols, they were always below 4.2. The difference between the values of ST-pH0 and PT-ZPC was only slight for the Andisols, whereas it was sometimes large (0.4 pH unit) for the Oxisols and Ultisols. Nevertheless, it was concluded that the ST method with its modification (STPT) was comparable to or even better than the PT method for the soil characterization work due to its convenience and simplicity. |
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| Keywords: | fly ash gypsum paddy soil rice silicate |
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