COMBINED EFFECTS OF BIOCHAR CONCENTRATIONS AND FERTILIZER TYPES ON UPLAND RICE DEVELOPMENT UNDER DRIP IRRIGATION SYSTEM

Abstract

This study evaluated the combined effects of biochar concentrations and fertilizer types on Rice (Oryza sativa L.) yield under drip irrigation system. The Upland Rice variety, New Rice for Africa (NERICA 2), was planted at the Teaching and Research Farm of Agricultural and Environmental Engineering Department, FUTA. Two experiments were conducted from October 2018 to April 2019 (season 1) and from October 2019 to April 2020 (season 2). The experiment was laid out in a Randomized Complete Block Design (RCBD) of four fertilizer types with four levels of biochar applications at 0 t/ha, 5 t/ha, 10 t/ha and 15 t/ha. The four fertilizer types were Liquid Organic Fertilizer (fertigation), NPK 15:15:15, Farm Yard Manure (FYM-poultry based) and Zero Fertilizer (control). The treatments were factorially combined to get 16 plots with three replicates each, making a total of 48 experimental plots, while water was supplied to all the plots through drip irrigation system. The combined application of fertilizers and biochar contributed significantly to inprovement in the soil’s physico-chemical properties such as Bulk Density, Base Saturation, soil pH, Organic Matter, Nitrogen, Phosphorus, Potassium and Cation Exchange Capacity (CEC). Average reference and crop evapotranspiration (ETr and ETc) estimated using Penman-Monteith-Model for the 16 weeks growth period was 27.01 mm/day and 24.55 mm/day in season 1 and 27.09 mm day -1 and 24.75 mm day -1 in season 2 respectively. Treatments NPKB15, PMB15 and LOFB15, in that order, performed well than F0B15 and F0B0 in agronomic parameters such as plant height, stem girth, number of leaves and leaf area in the two seasons. These parameters also performed well according to the biochar concentrations – B15, B10, B5 and B0 in that order. The highest average yield of paddy and processed rice of 6.31 t/ha and 6.20 t/ha in season 1 and 6.36 t/ha and 6.21 t/ha in season 2 respectively were recorded in NPKB15, followed by poultry manure with yields of 5.74 t/ha and 4.69 t/ha in season 1 and 6.00 t/ha and 5.07 t/ha in season 2 respectively in PMB15. Liquid organic fertilizer recorded the highest average yield ofpaddy and processed rice of 3.51 t/ha and 2.54 t/ha in season 1 and 4.55 t/ha and 4.08 t/ha in season 2 respectively in LOFB15, while Zero Fertilizer (control) recorded yield of 2.50 t/ha and 2.03 t/ha in season 1 and 3.36 t/ha and 3.26 t/ha in season 2 respectively in F0B15. There was a minimum of 50 % increase in paddy and processed rice yields in all the treatments when compared with the control (F0B0). NPK fertilizer at biochar concentration of 15 t/ha, which gave the best result in rice agronomic and yield responses is recommended as the best treatment for rice production under similar conditions as used in this study. Similar research should be carried out for three or more growth cycles on the same piece of land to ascertain if increase in rice yield would be sustained with the same one time biochar application.