Prediction and alternative conservation techniques of erosion at sugarcane plantation under wet tropical region

Soil erosion is a kind of the worst soil degradation phenomenon in the worldwhich could be due to soil mismanagement. The research aimedto predict the amount of soil erosion and to find out the alternative controlling techniques was conductedat sugarcane plantation in Lawang, Agam Regency and soil laboratory of Universitas Andalas, Padang, Indonesia.Soil sampling was takenat 5 slopes (0-8%, 8-15%, 15-25%, 25-40%, and >40%). Soil parameters were collected and analyzed at field and laboratory to get soil erodibility data.Soil erosivitywascalculated based on rainfall data in that area from the last 10 years. Soil erosion was predicted using USLE formula and tolerated erosion usingHamer concept. The results showed that eroded soil increased by steeperslope from 0 to 40%. The predicted soil erosion was higher than the tolerated one for each slope levelexcept under rather flat area (0-8% slope). The erosion hazard level in the research site belonged to low (for 0-8% slope), medium (for 8-15%), and high (for >15% slope). Therefore, alternative techniques should be introduced tocontrol the erosion, among which were soil hummock for all slope levels andterraces for steep slopes. Constructing traditional terrace at area having 8-15% slope, and perfect bench terrace at area having >15% slope would decrease the actual erosion from34.73 to 18.52 t/ha/y (at8-15% slope), from 147.4 to 6.55 t/ha/y (at 15-25% slope), from 415.4 to 18.46 t/ha/y(at 25-45% slope), and from 203.2 to 18.04 t/ha/y (at >40% slope).