Cowpea ( <i>Vigna unguiculata</i> (L.): maize ( <i>Zea mays</i> L.) intercropping and fertilizer application affected soil properties in Guinea savannah agro-ecological zone of Ghana

Maize–legume intercropping is a common strategy that improves land-use efficiency and resource utilization, especially in developing countries with limited inputs. The present study was conducted from March, 2021 to October, 2022 in Botanga and Golinga under irrigation conditions in Northern Ghana to evaluate the effects of maize-cowpea intercropping on some soil properties under different fertilizer regimes. Sole maize, sole cowpea, one row of maize and two rows of cowpea, and two rows of maize and four rows of cowpea were grown with no fertilizer, NPK fertilizer and compost as a 5 × 3 factorial in a Randomized Complete Block Design with three replications. The study revealed that maize-cowpea intercropping systems treated with either NPK or compost significantly (p < 0.05) increased soil carbon and organic matter and reduced soil pH. However, no significant improvements were observed in soil nitrogen, phosphorus, potassium, or bulk density. In Botanga and Golinga, nutrient amendments increased organic matter content by 9.43 and 19.21%, respectively. Farmers in the study areas should alternate rows of maize with rows of cowpea in either compost or NPK fertilizer-amended soils to maximize soil fertility. Liming of soils with hydroxides, oxides, carbonates and silicates of calcium and magnesium should be encouraged among farmers to ensure availability of nutrients in cereal-legume intercropping systems supported with nutrient application. Future studies could include the impact of intercropping and nutrient application on soil erodibility, rainfall erosivity, gravimetric soil moisture content and biological nitrogen fixation.