Degradation of coating material for chemical fertilizer in soils
1995
Tsubouchi, M. (Central Glass Co. Ltd., Ube, Yamaguchi (Japan)) | Yamamoto, K. | Yamada, N. | Marumoto, T.
Coating resin chemical fertilizer using alkyd resin and polyethylene resin is added into soils, and it is a problem that these resins remain in the soils. Therefore, we investigated the degradation of these resins in the soils. The results obtained were as follows. 1) the degradation ratio of alkyd resin was higher than polyethylene resin. Three month later, the former was 4.5% and the latter was below 0.5%. The result that the degradation ratio of alkyd resin was higher in soil with a high humus content suggested that the degradation of the coating material is microbiological. 2) There were no differences between alkyd and polyethylene resins in the number of microorganisms on the coating membrane surface and in the soil around the coating membrane, but the number of fungi in the former was about 100 times higher in the coating membrane and was about 10 times higher in the soil around the coating membrane than in the latter. In addition, using the trial box for the measurement of enzymatic activity, soil enzymatic activity concerned with the degradation of alkyd resin membrane was measured, and the results showed that the activity of the soil enzymes was high nearer the membrane. 3) Under field conditions, we took the buried membrane out of soils and observed its surface by electron microscopy. It was observed that the surface of the alkyd resin membrane was consequently degraded than the surface of polyethylene resin. These results definitely show that the alkyd resin membrane was degraded faster than the polyethylene resin membrane by the microorganisms in soils, and it thus appears to be a good material for use in coated fertilizer
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