Effect of Rice Husk Biochar and Inorganic Fertilizer on Growth and Yield of Lettuce (Lactuca sativa L.)

A field experiment was conducted from July to September 2024 at the Multipurpose crop nursery field of Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development, Mampong Campus, to evaluate the influence of rice husk biochar and inorganic fertilizer on soil properties, growth and yield of lettuce. The experimental design used was a Randomized Complete Block Design (RCBD) with seven treatments and three replications. The treatments were [(i) No fertilizer (control), (ii) 5 t/ha Rice husk biochar (RHB), (iii) 300 kg/ha NPK, (iv) 2.5 t/ha RHB + 150 kg/ha NPK, (v) 2.5 t/ha RHB + 100 kg/ha NPK, (vi) 1.25 t/ha RHB + 150 kg/ha NPK, and (vii) 1.25 t/ha RHB + 100 kg/ha NPK]. The results showed that 5 t/ha RHB and 1.25 t/ha RHB + 150 kg/ha NPK significantly enhanced the soil chemical properties (pH, P, N, K, Ca, Mg, OM and OC contents) as compared to the unamended plot and 300 kg/ha NPK treated soils. Lettuce plants that received 1.25 t/ha RHB + 150 kg/ha NPK and 5 t/ha RHB recorded significantly taller plants and higher number of leaves per plant than plants that received 300 kg/ha NPK from 2 to 5 WAT. The combination of 1.25 t/ha RHB and 150 kg/ha NPK showed significantly wider leaf area, canopy spread, highest shoot development, and overall yield (16.49 t/ha) as compared to the control (7.63 t/ha) and 300 kg/ha NPK (9.52 t/ha) treated soils. It is recommended that for enhanced soil fertility and higher yield, lettuce farmers should apply 1.25 t/ha RHB + 150 kg/ha NPK.