Planting Problems and Improvements on the Soil from the Tertiary in Osaka

Abstract

There is a soil which is called by the name of “Sei-kai nendo”(Bluish gray clay), in soils (from the Tertiary) on plateaus around plains of Osaka, Nara, Wakayama and Kyoto in Kinki District, Japan. At some places of the Senboku New Town, surfaces of the soil exposed to turn the land into housing lots about a dozen of years ago go on still being not covered by the vegetation. At such a places, root developement and soil weathering were investigated by means of the soil profile survey and soil analysis. As the retult, it was judged that it is caused by extremdly intensive acid, reduction and compaction of the soil.
The following two effective methods to grow plants on the soil through the growth of Raphanus sativus var. minor as a phytometer were found through the second experiment for the soil improvement, that is;
(1) to neutralize chemically the intensive acid soil by means of magnesium lime.
(2) to neutralize it by lime and furthermore to oxidize forcedly it by an oxidizing agent on sale.
Weathering the soil for two years was a little effective to improve it.