Agriculturae Conspectus Scientificus, Vol 89, No 1 (2024)

Effect of Biochar on Growth, Nodulation, Yield and Soil Properties of Cowpea

Aruna Olasekan ADEKIYA, Bolajoko Bisola AYORINDE, Elizabeth Temitope ALORI, Ojo Timothy ADEBIYI, Wutem Sunny EJUE

Pages: 27-36


It is necessary to search for an inexpensive soil additive capable of raising soil pH comparable to conventional agricultural lime. In 2020 and 2021 cropping seasons at the Teaching and Research Farm, Landmark University, Omu-Aran, Kwara State Nigeria, field experiments were conducted to evaluate the effects of various levels of wood biochar on soil chemical properties and bulk density, growth, nodulation and yield of cowpea (Vigna unguiculata (L.) Walp.). The soil of the experimental sites is an Alfisol classified as Oxic Haplustalf or Luvisol. The treatments were made up of five levels (0, 2.5, 5.0, 7.5, and 10 t ha-1) of wood biochar arranged in a Randomized Complete Block Design and each treatment was replicated three times. The application of biochar improved soil chemical characteristics (pH, N, P, K, Ca, Na, Mg and CEC), growth (vine length per plant, number of leaves per plant, leaf area/plant and tap root length), nodulation and yield parameters of cowpea (pod weight per plant and number of pods per plant) related to the control. Biochar application reduced exchangeable acidity relative to the control. The yield of cowpea was increased from 0 to 10 t ha-1 biochar rate. Using the means of the two years, relative to the control, application of biochar at 10, 7.5, 5, and 2.5 t ha-1 increased the pod weight of cowpea by 217, 118, 73 and 33%, respectively. This was adduced to a rise in soil pH and exchangeable cation and CEC and reductions in exchangeable acidity and soil bulk density which resulted in P solubility and availability, increased N fixation, enhanced root growth, increased nodulation leading to improved growth and yield of cowpea. Therefore, biochar can be used as an approach to improving the productivity of acidic tropical soil and hence improving crop productivity. Nevertheless, additional investigations are needed to show the rate of biochar that will result in optimum pH for cowpea production in the ecological zone.


biochar, cowpea, soil chemical properties, bulk density, pH, nodulation

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