Purpose Production of oil palm seedling in the nursery mainly utilises top soil as polybag medium. These soils, especially in tropical regions, are acidic and have low organic matter content. The aim of this study was to investigate the effects of oil palm empty fruit bunch (EFB) biochar and compost incorporation as amendment in polybag medium for oil palm seedlings growth at the nursery stage. Methods A polybag experiment was conducted with four biochar rates (0, 0.5, 1.0 and 1.5% w/w C addition), two compost rates (0 and 30% v/v), and two fertiliser application rates (75 and 100% of recommended rate). The effects of biochar, compost, and biochar-compost combination on oil palm seedling growth was evaluated and the effectiveness of EFB biochar in retaining soil nutrients was determined indirectly by measuring amount of nutrient leached through the polybag medium. Results Biochar, compost, and biochar-compost amendment improved polybag media's chemical properties (pH, total C and N, C:N ratio, CEC, Mg, and Ca). There were no significant effects of the amendments on shoot biomass. However, root growth and shoot:root ratio significantly improved with 1.5% w/w C addition and 30% (v/v) compost with 75% recommended fertiliser rates applied. Furthermore, nutrient leaching measurement indicates that, EFB biochar significantly reduced ammonium-N leaching up to 21-46%. Conclusions Overall, this study demonstrates the potential of biochar and compost co-application to improve the chemical properties of polybag medium and root development of oil palm seedlings.

W-Beam guardrail system has been in use as a standard for roadside safety barrier since 1950s. Recently, its safety performance standard has been upgraded to absorb impact from large vehicles. This performance standard requires guardrail system to be capable of capturing and redirecting a large range of vehicle types and sizes but its effects on safety of motorcyclists are not yet understood.The paper describes a three-dimensional computer simulation of the kinematics impact of motorcycle and dummy rider with W-Beam guardrail inclined at angles 45 and 908 to the initial direction of travel. The simulation is based on the test procedure recommended by ISO 13232 on the configurations for motorcycle-car impact. The focus of this study is not on the motorcycle change in velocity, but on the rider's kinematics and acceleration vs. time history.Multibody model of motorcycle and finite element model of guardrail were developed in commercially available software. The simulation results are presented in this paper in form of kinematics and acceleration vs. time history.