International Journal of Recycling of Organic Waste in Agriculture (IJROWA) Rice husk biochar and inorganic fertilizer amendment combination improved the yield of upland rice in typical soils of Southern Guinea Savannah of Nigeria Volume 12 (2023) Issue 3, July 2023 2023 11 17 Rice husk biochar and inorganic fertilizer amendment combination improved the yield of upland rice in typical soils of Southern Guinea Savannah of Nigeria 10.30486/ijrowa.2022.1951012.1409 EN Theophilus Olufemi Isimikalu Department of Agronomy, Faculty of Agriculture, University of Ilorin, Kwara State, Nigeria 0000-0003-4452-4263 John Olajide Olaniyan Department of Agronomy, Faculty of Agriculture, University of Ilorin, Kwara State, Nigeria Kehinde Olayemi Affinnih Department of Horticultural and Landscape Technology, Kogi State Polytechnic, Lokoja, Nigeria Okatahi Abdulmumin Muhammed Department of Horticultural and Landscape Technology, Kogi State Polytechnic, Lokoja, Nigeria Alexander Chubiojo Adede Department of Horticultural and Landscape Technology, Kogi State Polytechnic, Lokoja, Nigeria Abdullahi Haddy Jibril Department of Horticultural and Landscape Technology, Kogi State Polytechnic, Lokoja, Nigeria Emmanuel Atteh Department of Horticultural and Landscape Technology, Kogi State Polytechnic, Lokoja, Nigeria Segun Yusuf Department of Horticultural and Landscape Technology, Kogi State Polytechnic, Lokoja, Nigeria Taiye Juliana Ezekiel Department of Horticultural and Landscape Technology, Kogi State Polytechnic, Lokoja, Nigeria Journal Article 2023 11 17 Purpose Rice is a staple food in Nigeria, but its cultivation faces constraints of soil acidity, low soil fertility and rainfall variability. Research has shown that biochar has the potential to alleviate the effects of these conditions, but responses vary depending on soil and climate factors. Therefore, this study was conducted to evaluate the effects of different application rates of rice husk biochar on upland rice growth and yield. Method Two field experiments were conducted within two years in Kwara State located in the southern Guinea savanna agroecological zone of Nigeria. Four biochar rates (0, 5, 15 and 25 t/ha) were used and replicated thrice in a randomised complete block design set up on three soils in three locations. Agronomic data were subjected to analysis of variance (ANOVA) to quantify variations in treatment responses, followed by a separation of significantly different means using the least significant difference (LSD) at p≤ 0.05. Results Better growth was recorded in the first year compared to the second year. Percentage decreases of 9.4 and 11.4% were recorded in plant height (12 weeks after planting), and tiller productivity from the first to the second year, respectively. Biochar amendment significantly (p≤0.01) improved rice seedling emergence (34.6%) and seed weight (5.8%) relative to control. The highest grain yield of 5.24 t/ha was recorded under 15 t/ha biochar application rate compared to 2.37 t/ha under control. Conclusion The application rate of 15 t/ha increased rice yield by 55.0% relative to the control, whereas at 25 t/ha the growth and yield were reduced.   Highlights Biochar amendment brought faster growth and maturity of rice plants Upland rice yield decreased at biochar application rate beyond 15 t/ha Rice husk biochar improved upland rice yield in poor fertility loamy and sandy soils Rice yield under biochar amendment were lower in the second year of experiment than in the first year