@article{oai:u-ryukyu.repo.nii.ac.jp:02006674, author = {鎮西, 忠茂 and Chinzei, Tadashige}, issue = {4}, journal = {琉球大学農家政学部学術報告, Science bulletin of Agriculture & Home Economics Division, University of the Ryukyus}, note = {1. Soils in southern Okinawa are mostly derived from calcareous clay (marl) or Ryukyu Limestone (coral reaf). The author collected seventy-nine soil samples from twenty four localities in the southern part. of the island and tested them by the Spurway Soil Test method for the same purpose as in the previous papers. 2. Soluble magnesium was generally high in most soil samples. indicating that the piants should not suffer from lack of this element. 3. Many samples gave negative, or low reserve test for iron which indicate, the possibility of iron deficiency in plants. No soils were found with toxic level of iron. 4. Negative active test for manganese were given in all samples except one soil which was the only one derived from a palaeozoic shale in the south of Okinawa. And also low reserve test were given in most samples. These results indicate the possibility of manganese deficiency in plants. 5. Test for sulfates were negative in all soil samples. However, soils may not be deficient in sulfur because the lower limit of the sulfate test by the Spurway Soil Test method is 20 ppm. 6. Tests of other than the above elements were also made, and the results are summarized as follows: a) Most soils were low in available nitrogen content. b) As to available phosphorus, there were several samples which gave considerable high reserve test. One of them was 160 ppm. in reserve test which is in the excess range of phosphorus. c) Reserve test for potassium were less than 20 ppm. in most soil samples. d) Ca^<++> content in reserve test were mostly high as may be expected from their reaction of a high pH. It is evident that most soils are immature, or lithosolic. These facts indicate that most soils in southern Okinawa are unsuitable for most acid-soil crops, for instance pineapple, tea and other acid. loving plants. e) Al^<+++>, Cl^- and N0_2- were all below toxic levels. 7. Elements other than the above were not checked because the Spurway Soil Test Kit does not include such testing methods., 紀要論文}, pages = {169--179}, title = {琉球産土壤の微量要素に関する研究 1. Spurway Soil Test Kit による予備試験 4. 沖縄島南部産土壌} }