SIMULATION OF BEHAVIOR OF FERTILIZER MATERIALS IN SOIL : II. On Potassium Release from Slowly Soluble Potassium Silicates in Soil Column
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概要
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As a trial of the quantitative evaluation of the availability of slow-release fertilizer, the dissolution and transport of K from slowly soluble potassium silicates (KSi) in soil columns were investigated by the simulation. The model of tri-ionic exchange chromatography was improved to include the source term of KSi. The column leaching experiments were carried out using K_2O・5SiO_2 (KSi5) and K_2O・6SiO_2 (KSi6). The results were compared with the computed ones. In the experiments, K^+ released from these slowly soluble KSi accumulated in the exchanger phase of the soil at the layer of placement and the next 2cm layer, while NH_4^+ from NH_4Cl moved downward to give broader distribution. These characteristic distributions owing to the dissolution rate of the materials were reproduced well by the simulation of the each experiment. The effect of granule or particle size on the K dissolution from KSi was investigated by the simulation of the column leaching under the water flow of 30 mm/day and at 25℃. The abilities of KSi5 and KSi6 to supply plenty of K, estimated by total K dissolved during 80 days in the soil (T_<sk>), decreased with increasing granule or particle sizes of each material. The pattern of K release during a long term, estimated by the rate of decrease in the amount of K dissolved in each successive period of 10 days (D_<r10>), decreased with increasing sizes. T_<sk> and D_<r10> were related to "Generalized Solubility Variable (GSV)" which was given by kC_sS_0 (product of rate coefficient, k; solubility, C_s; and initial total surface of the granules or particles, S_0). It was indicated that the desirable K released from KSi may be obtained by selecting the value of GSV within a certain limit.
- 社団法人日本土壌肥料学会の論文
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関連論文
- SIMULATION OF BEHAVIOR OF FERTILIZER MATERIALS IN SOIL : II. On Potassium Release from Slowly Soluble Potassium Silicates in Soil Column
- SIMULATION OF BEHAVIOR OF FERTILIZER MATERIALS IN SOIL : I. Model of Tri-component Exchange Chromatographic Transport