Application of the described method to other soils
" cen-
To prove the usefulness of the method, developed for the Kochel Moos
area, thermal scanner data of three other areas with different soils
jer were processed in the same way. Fig. 12 shows the results.
0
ated The Sindelsdorf and Iffeldorf areas are situated at about 5 - 10 km
north of Kochel Moos area (see fig. 1). Sandy soil covers fluvial gra-
vels of changing grain sizes. The difference between Kochel Moos and
Iffeldorf is marked by a higher morning temperature at Iffeldof. In
this area, too, small scale variations, i.e. variations in prevalent
grain size, could be detected on the basis of heating gradients.
>
fe- The last test area "Reichelsheim" is situated north of Frankfurt in the
s- Wetterau. Loamy soils predominate. The comparison with the Bavarian test
areas seens to be difficult because year and month of the flights are
different. But fig. 12 shows that gradients and morning temperatures
re differ from those of sandy and peaty soils. In the Reichelsheim area,
g too, temperature gradients allowed to distinguish between loam and
em- loam with a thin coverage of sand.
As mentioned before the data processing was carried out manually.
ndence Therefore temperatures were averaged over squares of 30 m by 30 m. The
0. comparison between the "thermal maps" and existing maps shows that this
geometric resolution is convenient for soil mapping. Moreover it seems
its to be necessary in a region were small scale variations in the soil
se caused by intensive land use and treatment can hide original soil
d characteristics.
em-
ties Conslusions
trol.
Utilizing heat flows during night time in combination with thermal scanner
the data it is possible to calculate soil moisture in grass covered areas
W with an accuracy of + 10 %. The results can only be referred to the
rences upper 0.1 m. But those calculations include many ground truth measurements.
able Density of the soil lei), temperatures of the soil and air tempera-
lative ture at + 0.2 m. Even assuming a map of soil densities, for every den-