Abstract
The objective of this study was to determine the suitable type and dosage of biochar derived from agricultural and forestry by-products for the growth and yield of the HT1 rice variety, as well as to improve certain soil chemical properties under net-house conditions in Hue city. A two-factor experiment was conducted using four types of biochar (rice straw, rice husk, sawdust, rice straw + rice husk + sawdust (ratio 1:1:1)) and four biochar concentrations (0 - control, 1.25, 2.50, 3.75 g/kg soil) . The results showed that the types and rates of biochar affected growth indicators such as plant height, leaf area, SPAD index, fresh and dry biomass of rice stems, leaves and roots, as well as rice yield. Applying biochar (2,50 g/kg soil in the type of biochar from rice husk and combined rice husk, rice straw and sawdust) resulted in 45% and 47% higher rice yields compared to no biochar application. Biochar supplementation also improved some soil chemical properties, especially at rate of 3,75 g/kg soil at 4 types of biochar application. Further field research is needed to comprehensively evaluate the effectiveness of biochar types and rates on the yield of HT1 rice variety, economic efficiency, and soil properties in the future.