direction there is a ground moraine plateau with local diapirs of 
sand at domes. Here loamy underlaid sands are encountered that 
are partly slack or ground water influenced and have a different 
top sand layer thickness (fig. 3). The usable water capacity of the 
soil up to lm under field is at most 160 mm, because of the 
strongly changing thickness of sand the soil moisture regime as a 
whole is a decisive yield factor. The considerable heterogenity of 
the soil features in the test area is expected to give a 
remarkable time-spatial differentiation in yield formation of the 
agricultural crops. 
On two days during the experiment airborne radiometer missions 
with six lines per flight were conducted. During the period of the 
measuring dates there was dry weather, the moisture of the upper 
soil layers measured at a total of 32 ground control points 
decreased of 2 - 5 % (fig. 3). At noon the temperature of the 
upper soil which on the first date was still at 25°C on the 
average had increased to about 30°C on the second date. The 
vegetation too faced shortage of water, the plant moisture 
decreased of 4 18%, the temperature of the leaf surfaces 
increased from 17°C to 23°C on the average. In part however these 
changes can also be deduced by the process of beginning 
senescence . 
In the measurement profile the Havel channel was first stressed 
significantly with brightness temperatures of 180 K. Important 
vegetation areas were a small forest, a field of sugar beets as 
well as rows of trees along the road and field path. Corn and 
grassland for the given microwave band is opaque, so a differen 
tiation of soil moisture over these fields was not expected. The 
microwave signal, however, shows a different increase of the 
brightness temperature during the time of both dates indicating 
the decrease of moisture on major parts of the test sites 
investigated (fig3). Areal extrapolation made from the flight 
lines showed only some areas near the channel with a exceptional 
behaviour . 
The decrease of the brightnes temperature indicating an increase 
of moisture for plot 570 (sugar beets) can be explained by the 
stepping plant growth considering the sugar beet plant structure