The under ground heating system by warming water was one of the mordern, most approyed system of heating in a greenhouse, because the under ground heating was directly controlled the temperature of soil for many greenhouse crops.
This study was the objective to the materials in order to design the systems of under ground heating units.
Accordingly, this study dealt with the relationship between thermal conductivity and temperature, water content of soilFor measurement of thermalconductmty of soil, the stational method was used.
As the experimental result, it was cleared that the temperature had no influence over the apparent thermal conductivity(λ), and the correction figure(β) in relation to the soil characteristic increased in about 5% of volume water content, and the value of apparent thermal conductivity(λ) was silghtly larger than the value of real thermal conductivity(λ_h).