Profitability of Upland Rice (Oryza Sativa L.) Production under Different Weed Management Systems, Sources and Rates of Biochar in Kaduna State, Nigeria

Field trials were carried out concurrently during the rainy season of 2024 on the research farms of the Institute for Agricultural Research, Zaria (11o11ꞌN; 07o38ꞌE 686m above sea level) and Kaduna State College of Education, Gidan Waya (9o34ꞌN, 8o18ꞌE 740m above sea level) located in the northern and southern parts of Kaduna State, which also coincides with the northern and southern Guinea savanna ecological zones of Nigeria, respectively. The experiment was carried out to assess the profitability of upland rice (Oryza sativa L.) production under different weed management systems, source and rate of biochar. The treatments consisted of three different weed management systems [chemical weed control (Saflufenacil + Dimethenamid-P at 0.5 kg a.i/ha applied pre- emergence), integrated weed control (Saflufenacil + Dimethenamid-P at 0.5 kg a.i/ha applied pre- emergence + one hand weeding at 63 DAS) and cultural weed control (Hand weeding at 21, 42 and 63 DAS)], three sources of biochar (groundnut shell, maize cob and wood shavings) and three rates of the biochar (0, 2 and 4 t ha-1). All the treatments were laid out in a Split-Plot Design and replicated three times. The three rates of biochar and three different weed management systems were factorially combined and laid out as the main plot treatment. The sub-plot treatments consisted of the three sources of biochar. The results showed that application of Saflufenacil + Dimethenamid-P at 0.5 kg a.i/ha + one hand weeding at 63 DAS in combination with groundnut shell biochar at 2 t ha-1 gave the highest yield of 3,546 kg/ha and 4,106 kg/ha at Zaria and Gidan Waya, respectively. This also corresponds to the highest return on investment of ₦571,900 with a profit of ₦1.82 per every naira invested at Zaria and ₦702,300 with a profit of ₦2.17 per every naira invested at Gidan Waya. Therefore this treatment is considered most appropriate and profitable for upland rice production in Kaduna State, Nigeria.