Effect of trachyte and basalt rock powders on maize (Zea mays L.) growth and yield on Fluvisols in Cameroon’s Sudano-Sahelian zone (Central Africa)

Abstract. The Sudano-Sahelian zone of Cameroon, characterized by a low annual rainfall, faces challenges in soil fertility preservation due to agricultural intensification and unsustainable practices. This study aims to evaluate the effect of trachyte and basalt powders inputs on soil and maize yield in Guiring experimental farm. Fieldwork involved collecting and describing samples of trachyte, basalt, and soil and setting up the experimental design. In the laboratory, the ground rock samples underwent geochemical analysis, and the soil samples were analysed for their mineralogical and physicochemical properties. The experiment followed a completely randomized block design with six treatments (T₀, T₁, T₂, T₃, T₄, and T₅) and four replications. Growth and yield parameters of maize, include germination rate, plant height, number of leaves per plant, stem diameter, ear length, ear diameter, ear weight, 100-grain weight, and grain yield (kg ha^-1). The soil consists of kaolinite, smectite, sepiolite, and quartz. Its texture is dominated by sand fraction, with a neutral pH (7.0). The organic matter (2.6±0.67 %) and total nitrogen contents (0.1±0.0 %) are relatively low. The concentrations of potassium, magnesium, sodium, and calcium are 0.2±0.1 cmol_c kg^-1, 2.5±1.6 cmol_c kg^-1, 0.3±0.2 cmol_c kg^-1, and 3.9±1.5 cmol_c kg^-1, respectively. The cation exchange capacity is moderate to high (22.1±2.5 cmol_c kg^-1), while the available phosphorus content is high (19±7.0 mg kg^-1). This soil is classified as Ochric Dystric Fluvisols according to the WRB. These soil characteristics are moderately suitable for maize cultivation. Fertilization trials showed a significant improvement in maize growth and yield, within plots treated with basalt powder yielding higher (2558.6 kg ha^-1 and 2931.2 kg ha^-1) than those treated with trachyte powder (2362.9 kg ha^-1 and 2763.9 kg ha^-1) and the control plots (645.8 kg ha^-1). Plots treated with NPK fertilizer recorded the highest yield (3164.5 kg ha^-1). Although the treatment with conventional fertiliser resulted in a relative higher yield, the advantage of using rock powders lies in their environmental benefits, long-term effectiveness, and more affordable cost.