The research on influence of chemical fertilizer for dispersion, flocculation and sedimentation of the Kunigami [Okinawa, Japan] maaji soil
2004
Yoshinaga, A. (Ryukyu Univ., Nishihara, Okinawa (Japan). Coll. of Agriculture) | Sakai, K. | Tokashiki, Y.
Abstract The storage water suspended in a sedimentation tank for several days can be seen very often in the Kunigami Maaji area These phenomena occur in cases where the effluence of muddy water from field is contaminated by chemical fertilizers, which makes it more difficult to remove the sediment of fine soil particles and exasperates the pollution of river and sea areas. In order to demonstrate the influence of chemical fertilizer extended to the long-term suspension phenomena, this research was conducted for the analysis of water-stable aggregates; testing of the settlement of muddy water contaminated and uncontaminated by chemical fertilizer; and for the analysis of the particle sizes of suspended soil. As a result, it was clarified that chemical fertilizers have the dispersion effect and the flocculation settling inhibitory effect which become the reasons of long-term suspension. It was also clarified that phosphate components profoundly affect the dispersion and flocculation settling inhibitory effects. In most cases of the water suspended in the Kunigami Maaji area in the Okinawa islands, the settling is inhibited by chemical fertilizers.
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