Runoff and sediment were intercepted using a 1 m wide Gerlach trap

Runoff and sediment were intercepted using a 1 m wide Gerlach trap
(Gerlach, 1967) installed with a 40 L collector plastic tank. Total runoff
and soil loss were measured after each erosive event (i.e. an event producing measurable runoff) or, occasionally, after a series of events if
they were separated by a short time interval. The tanks were weighted,
the content of each tank was carefully mixed and 1 l sampled, dried at
50 °C and stored for chemical analysis. The erosion was calculated
using the concentration of the sediment per liter and related to the
total weight of the tank. The weight of the empty tank was subtracted
from the total weight.
Soil samples were collected at the beginning of the experiment (November) and after three months (February) in each plot. Three soil subsamples of each plot were taken at 0–15 cm and 15–30 cm depth along
the plot with an interval of 2 m from C4-SOC strip. The positions with respect to the plot are referred to as: upper (2 m), middle (4 m) and lower
(6 m) trams (Fig. 2). Furthermore, three soil subsamples for each plot
were taken in the C4-SOC strip (Fig. 2). All the soil samples were airdried and sieved with a 2 mm sieve for laboratory analysis.