More important, however, is the fact, that the curves for moisture 
values greater than 30 Z take a vertical course. That means, that higher 
water contents cannot be determined by experimentally gathered tem- 
perature gradients but they have to be calculated on the basis of quan- 
titative knowledge of all parameters which influence the physical pro- 
cess of heating the soil. But even the temperature gradients of samples 
with lower water contents vary considerably. 
Further limits of the method are given by the definition of thermal 
inertia. Moisture calculations can only be carried out if specific heat 
capacity and heat conductivity are known. Heat conductivity includes 
the fraction of air in the soil; but air contents depends on water con- 
tents, which is unknown. 
Thermal inertia and soil mapping 
Although thermal inertia does not seem to be useful for calculations 
of soil moisture, it can be taken as complex indicator for soil pro- 
perties. Therefore a method had to be found which allows to map soil 
differences in spite of an intensive land use pattern which hides 
borders between soil units. 
Basis for this research were thermal scanner data taken at 1000 m above 
ground before sunrise and before noon. The data were calibrated by the 
black body temperatures of the scanner and intersected in intervals of 
1,25 °C (night time) and 2,5 °C (day time). 
First attempts were made in the Kochel Moos area, where the following 
combinations of soil and vegetation were distinguished: 
- drained areas separated in fields with mown grass and in those 
with not mown grass, 
- poor drained areas and marginal parts between drained and undrained 
areas, 
swampy areas which were covered by much dead rush and reedgrass.