Modeling rainfall influence to soil sediment yield in corn monocropping systems in Claveria, Southern Philippines through Water Erosion Prediction Project (WEPP)

Abstract

In this study, the Water Erosion Prediction Project (WEPP) was used to model the soil sediment yield in four monocropping systems in Claveria, Misamis Oriental in Southern Philippines, as influenced by rainfall. The rainfall data were analyzed and inputted into the WEPP model, together with the soil, climate, and other relevant data in Claveria. The sensitivity analysis was performed using four corn monocropping systems (CMS), including no-till (NT), light till (LT), medium till (MT), and heavy till (HT), considering rill cover, effective hydraulic conductivities of the soil, increasing annual rainfall, and rainfall-runoff factors. The WEPP model indicated that soil sediment yield is highly sensitive to the type of tillage practice and the increased rainfall in Claveria. Claveria’s average annual rainfall is over 3000 mm with nine rainy months and three dry months. During the 13 years, the annual rainfall increased by 28%, which is equivalent to 68 mm/year. The average annual erosion rates increased by 114%, 85%, and 54% in LT, MT, and HT CMS, respectively. One management option to keep sediment yields to an acceptable level is to shift from HT or MT systems to NT or LT systems, which maintain high levels of residue cover on the soil.