Strongly acidic soils distributed throughout the plateaus

Abstract

In recent years, road construction work and land development are being carried out on a large scale using construction machinery. Due to this, the soil has become strongly acidic causing a serious problem to slope seeding and planting. The author collected many soil samples of this kind from 5 places throughout the whole country (Hokkaido, Ishikawa, Shizuoka, Kumamoto and Okinawa) and conducted some fundamental experiments on them
The conclusions obtained are summarized as follows:
1) Soil color is almost bluish-gray and olive-gray except for Kumamoto soil.
2) pH of the soils indicates oxidization of about 2 to 3.
3) Soil hardness is about 16-31mm, electrical conductivity ranged from a minimum of 1.3mΩ/cm to a maximum of more than 10mΩ/cm.
4) Specific gravity of the soils is about 2.4-2.7, and texture consists mostly of silt fraction and clay fraction.
5) Three phases of the soils is extremely low in the gas phases with a large water retentivity
Strongly acidic soils may be due to the large amounts of mudstone accumulated during the Neogene period, Pleiocene epoch and the Quaternary period, Pleistocene epoch.