2.1.4 Crop yield loss calculation
The total loss of crop production in the watershed was calculated by
multiplying the total surface area coverage of the gully (area of land
devoid of production because of gully erosion) and the productivity of
the Teff crop. To find the main causes of gully formation and
development frequent field visits and observation during the 2017 rainy
season, interview with farmers working in their fields using transect
walks and discussion with development agents (DA) working with farmers
in the watershed long years have been conducted.
2.1.5
Dry soil mass and bulk density calculation
To calculate the dry soil mass lost from volumetric measurements, soil
density was required. Hence, soil samples were collected. The first
sample was taken 50 cm below the edge of the gully, the second sample
was taken at the middle and the third at 50 cm above the gully bed using
cylindrical core sampler. The collected samples were oven-dried at 1050C in the laboratory and density was calculated
weighing the dried sediment and subtracting it from the wet sediment
mass.