A Study of Soil Erosion and Sedimentation Between Two Different Seasons in Sembrong Catchment Using Cesium-137

Incidents of soil erosion and sedimentation occur frequently in catchments area around the world as a result of human activities and the impacts of global climate change. This research paper aims to determine the rate of soil erosion and sedimentation by using Cesium-137 (¹³⁷Cs) as a medium-term tracer in the Sembrong catchment over two different study seasons. The Sembrong catchment area is located in Kluang, Johor and is one of the most important ecosystems in Peninsular of Malaysia. Soil and sediment samples were collected using a standard metal corer and integrated suspended sediment trap samplers. A total of 50 samples were collected at 20 sampling stations consisting of various land uses in the vicinity of the site for both the dry and wet seasons. The dry season of soil erosion rate ranged between 5.09 t/ha/y to 65.2 t/ha/y. Meanwhile, soil erosion and sedimentation rates during wet season ranged between 8.02 t/ha/y to 39.78 t/ha/y and -4.81 t/ha/y to -50.81 t/ha/y, respectively. Rubber and oil palm plantations referring to station 17, stations 4 and 6 located near Sembrong Lake and Sembrong River had the highest rates of soil erosion and sedimentation at 51.03 t/ha/y and -50.81 t/ha/y, respectively. This situation may be due to the fact that rubber and oil palm plantations in these two areas are still new planting areas and allows the rainfall received in both seasons to continue to penetrate into the soil. In conclusion, ¹³⁷Cs as a medium-term tracer was successfully used to determine rates of soil erosion and sedimentation in two different seasons for the Sembrong catchment area. The data on soil erosion and sedimentation rates will be very useful for present and future land and water management in the Sembrong catchment area, and may be compared with other similar catchments in Malaysia. (author)