Assessment of the effects of liquid and granular fertilizers on maize yield in Rwanda

Abstract

Maize (Zea mays L.) is the most widely grown cereal in the world, accounting for 1,116.34 MT of production in 2019/2020. In Africa, this crop represented approximately 56% of the total cultivated area from 1990 to 2005. About 50% of the African population depends on maize as a staple food and source of carbohydrates, protein, iron, vitamin B, and minerals. Lately, maize has become a cash crop which contributes to the improvement of farmers' livelihoods. For example, the Strategic Plan for Agricultural Transformation (SPAT) III outlined that fertilizer availability in Rwanda should increase to 55,000 MT per year, while fertilizer use should increase from 30 kg/ha in 2013 to 45 kg/ha for the 2017/18 cropping season. Only inorganic fertilizers are currently being used in maize production in Rwanda. This research was conducted to assess the effects of liquid (CBX: Complete Biological Extract) and granular fertilizers on maize crop yields in Rwanda. The study was conducted in the fields of the Rwanda Agriculture and Animal Resources Development Board (Rubona Station) during the 2018/2019 cropping season. Analysis of variance (ANOVA) was used to determine whether differences between treatments were statistically significant, with the threshold for statistical significance set at p < 0.05. Aboveground biomass differed significantly between treatments, with maximum and minimum values of 11,475 kg and 7,850 kg, respectively, being observed. Furthermore, the harvest index differed significantly between treatments, with minimum and maximum values of 0.2136 and 0.33, respectively, being observed. Grain yield also differed significantly between treatments, with the highest value (3,053 kg/ha) observed for a treatment which applied liquid and granular fertilizer at equal proportions (treatment 8), and the lowest one was found in treatment 3 with 1,852 kg/ha. In this study, the gap between the lowest and highest grain yields was about 39.3%. In conclusion, the combination of organic liquid fertilizer and granular fertilizer can significantly increase the grain yield of maize in Rwanda.