Impact of forest conversion to agricultural plantation on soil erosion

¹ Department of Water and Environmental Engineering, School of Civil Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
² Centre for Coastal and Ocean Engineering (COEI), Research Institute for Sustainable Environment, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
³ Centre for Environmental Sustainability and Water Security (IPASA), Research Institute for Sustainanble Environment, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia

^* Corresponding author: kogila@utm.my

Abstract

Agriculture in Malaysia makes up to twelve percent of the nation’s GDP and is supplying one-third of the world rubber export. Ambitious agriculture demand increases the intensity of forest conversion which is driven to the soil erosion. Thus, this study is to measure and analyse the impact of forest conversion on soil erosion relate to some manipulated variables such as slope, bulk density, soil moisture, canopy openness and ground cover, where rainfall and soil type are constant within the sites. Two different land-uses of High Conservation Value Forest (HCVF) and Mature Rubber Plantation of Timber Latex Clone (MRP) were selected around Kelantan state, due to the high land conversion compared to the other states of West Malaysia. Ground height change was monitored by using Modified Laser Erosion Bridge (MLEB) in between 17 to 48 transects. The result found that the annual soil erosion rate was 76.12 t.ha^-1.yr^-1 for HCVF is higher compared to the MRP was 6.37 t.ha^-1.yr^-1. Terrace soil conservation technique is practiced for MRP helps in reducing soil movement resulted significant low erosion rate compared to the HCVF. The results indicate that even a relatively limited forest conversion can be assumed to have a significant effect on regional soil erosion rate.