Deficient soils of micro heavy elements and its stratigraphic relation on the terrace in the Miyazaki coastal plain, south Kyushu, Japan
1994
Nagatomo, Y. (Miyazaki Univ. (Japan). Faculty of Agriculture) | Rahman, S. | Hossain, B. | Takaki, H. | Tamai, M.
On the terrace in the Miyazaki costal plain, a physiological disease chlorosis of leaves, observed on the citrus trees grown area on some Andosols. This chlorosis was similar to the mottle leaf which is the typical Zn deficiency symptom of citrus tree. In this investigation, contents of some heavy metal elements, Zn, Cu, Fe and Mn, were determined with the soils and citrus leaves collected in that area to make clear the cause of this chlorosis symptoms appearing. In the same time, the origin of the soil in which the disease observed was studied geomorphologically and stratigraphically. The following results were obtained. Among the micro heavy elements contained in citrus leaves, the Zn content was apparently lower in the leaves of disease trees (10.8 ppm) than that of the normally growth trees (16.2 ppm). The available Zn of soil, extractable Zn with 0.1 N-HCl, was lower in the soils (3 ppm) in which the disease citrus trees were grown that normal soils (7 ppm). It is presumed that the chlorosis symptoms were caused by the deficiency of Zn. On the other hand, there may exist some influences of imbalance among some nutrient elements in plant and soil. Based on the stratigraphic relation, it is considered that the soil profile of this area is the same that of Koki-hyuga loam and that the horizon of low content of available Zn was formed with Awaokoshi scoria erupted from the Kirishima volcano
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