Applicability of used disposable diapers for soil amendment and the effect of calcium supply

In recent years, the demand for disposal diapers has been increasing with population aging. We examined the applicability of using used paper diapers as soil improvement materials. Komatsuna were cultivated by using Entisols and Andosols with applying the materials that were recycled from disposal diapers. Diaper ash was prepared by sufficiently incinerating used disposable diapers at 800?℃ after they were dehydrated, washed, sterilized, and deodorized, and the calcium material with saturation by calcium chloride solution that were assumed the recycled super absorbent polymers of disposable diapers were used for materials. The prepared diaper ash and calcium material were applied to both soils. The shoot fresh weight and shoot dry weight of the plant with the diaper ash and calcium material were significantly higher in the case of the Entisols, and that with the diaper ash was significantly higher in the case of the Andosols. The calcium absorption amount in the plant was significantly high after the application of calcium material on the Entisols and that of diaper ash on Andosols. Overall, it was concluded that used disposable diaper can be used as the soil acidic correction and calcium materials and that they effectively promote plant growth.