Five elements (Cu, Fe, Mn, Pb and Zn) were quantitatively analyzed on 122 samples of grasses including fodder crops collected at five districts of the Okinawa main island. The results showed that each element differed considerably according to harvested districts and to species of grasses. Especially variation in lead content was remarkable. Compared with fodder crops produced in Japan, avreage amounts of trace elements of grasses produced in Okinawa were larger for copper and iron and smaller for manganese and zinc.
　Aknowledgements : The authors are indebted to the Livestock Sec., Economic Bureau of the Okinawa Gov't., the Serum Producing Laboratory for Livestock Diseases, the Haneji and Ishikawa Stockbreeding Stations; the Nago and Koza Agricultural Research and Guidance Officer, the Central Agricultural Research and Guidance Office and the other local agencies, and Dr. Akio Sugawa who used to work for the Livestock Hygiene Experiment Station of the Ministry of Agriculture and Forestry. They were very cooperative in providing the authors with analytical materials for this experiment.