Estimation of Agroforestry Land Erosion Based on The Water Erosion Prediction Project (WEPP) Application

ABSTRACT
The existence of land productivity is decreasing day by day, this is caused by the rate of
erosion. The characteristics of agroforestry land those are not suitable for its designation will
also result in decreased land productivity. Increasing the rate of erosion can make
sedimentation in rivers and reservoirs more and more. Villages in the Pujon Malang subdistrict
include villages that are in landslide-prone areas and most of them are at high risk of
landslides, droughts, and flash floods. This study aims to identify the value of erosion on
agroforestry land based on the WEPP application and to identify the value of the
classification of erosion hazard classes resulting from the erosion estimation using the
WEPP application. Primary data collection in the field includes soil sample data in the form of
soil texture, soil depth, albedo, percentage of sand, percentage of clay, percentage of
organic matter, value, exchange capacity, % rock, and albedo. Secondary data in the form of
rainfall data, topography, soil types, and land use. The total value of the erosion rate that
occurred was 657,700 tons/ha. The total erosion value comes from 364.715 tons/ha for
agricultural land, 8.898 tons/ha for agroforestry land as much as 283,200 tons/ha for
settlements, and forest land for as much as 0.882 tons/ha. The total value of soil erosion that
occurred was 657,700 tons/ha. The erosion value belongs to the Erosion Hazard Class V
including very heavy erosion.