COMPARISON OF ACTINOMYCETE FLORA BETWEEN TROPICAL AND TEMPERATE UPLAND FARM SOILS .1. PHYSIOLOGICAL-CHARACTERISTICS

Actinomycete flora in upland farm soils was compared between tropical (Thailand) and temperate (Japan) areas. The percentage of chromogenic-positive actinomycetes to the total isolates was 52.4% on the average in the soils of Thailand and 11.9% in the soils of Japan with a significant level of 0.1%, while that of protease.positive actinomycetes was 60.1% in the former soils and 46.1% in the latter with a significant level of 2.5%. The percentage of cellulase-positive actinomycetes to all isolates of actinomycetes in the soils of Thailand was very high, amounting to 77.3%, while that in the soils of Japan was 29.1%. The percentage in each soil of Thailand was higher than that in any soils of Japan. A significant difference in the composition of actinomycete flora between the tropical and temperate soils, and marked difference among major tropical great soil groups were recognized. A correlation between carbon contents in soils and the ratios of chromogenic actinomycetes to the total isolates was obtained with a significance at the 1% level. It was also noticed that the chromogenic group contained high percentage (70%) of colonies positive to both protease and cellulase, in contrast to the non-chromogenic groUP (24%). These results indicate that tropical soils contain predominantly chromogenic actinomycetes with strong protease and cellulase activities and this trend is particularly evident in soils with low carbon content. © 1979 Taylor & Francis Group, LLC.