Stefan Wirtz Vom Fachbereich VI (Geographie/Geowissenschaften ...

Experimentelle Rinnenerosionsforschung vs. Modellkonzepte – Quantifizierung der hydraulischen und erosiven Wirksamkeit von Rinnen
were spread in a 10 x 10 cm pattern (see fig. 2c). After the passing of 3 x 15 goats (= 45
goats), the translocation vector (distance and angle) of each rock fragment was measured.
The original position of each fragment was marked by a nail that was driven into the ground.
The resulting values were categorized into 4 segments according to the measured angles:
- (1) 0-89° forward-downslope
- (2) 90-179° backward-downslope
- (3) 180-269° backward-upslope
- (4) 270-359° forward-upslope
Since the bulk of our rock fragments landed in segment 1, this segment was further divided,
allowing for a more precise interpretation:
- (1a) 0-44° forward-forward-downslope
- (1b) 45-89° downslope-forward
Later on, we applied the law of sines to calculate the vertical up- and downslope translocation
distances of all moved rock fragments.
Experiment 4: Loosening quantity
The test plot of the 4 th experiment had a rectangular footprint of 4 m x 0.5 m (see fig. 2d) and
was characterized by a flat, crusted surface. It was covered sparsely by dead vegetation (about
5 %); rock fragments were not present. A flock of 15 goats was guided over the test plot 4
times (= 60 goats) before it was swept with a regular hand broom. The loosened fine material
was collected and weighed. This procedure was repeated 10 times in order to simulate the
gradual loosening process of a soil crust caused by a flock of 600 animals.
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