Abstract:
Paddy field in Sendai area has suffered a huge damage after the Tsunami, caused by the great earthquake on 11th March 2011. Thick sludge covered the paddy field after brine receded, and some part of this field still became uncultivable. To restore cultivation, firstly the soil must be desalted, and then many lost nutrient elements should be resupplied. For the desalting of soil, the sodium absorbed by soil particles has to be removed by the supplement of calcium, and for the growth of rice, silicate is the most important nutrient. In such circumstances, the steelmaking slag, which is suitable for the above two purposes, has been proposed as a solution for recovery. Some trials have been made to the damaged paddy field in these years to clarify the effect of steelmaking slag addition. The existence of steelmaking slag promotes the paddy growth during sprouting and maturity season. Also within those periods, the paddy grows even better than in the normal cropping condition. In addition, for the clarification on the mechanism to supply nutrient elements form steelmaking slag, experiments by column incubation methods are conducted. In this experiment, the mixture of air dried soil with slag is loaded in a PVC pipe, then irrigated with water to simulate the paddy field condition and measure the dissolution behaviour of each element. The effect of slag as a fertiliser is clarifying quantitatively with this method.
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