In general, rates of applications per hectare in Ghana average around 90 kg N. 60 kg P2O5 and 60 kg K2O. However, fertilizer N levels up to 120 kg/ha are recommended for cultivation in degraded soils. When your soil is tested for fertility status and pH levels, you can be informed about the additional amount of fertilizer needed to meet target yields.
The number of bags of each fertilizer needed per hectare depends on the amount of N, P and K contained in the grade of fertilizer you purchase. Seek help from your local agro-input dealer and agricultural extension agent to determine the number of bags you will need for your plot. Animal manure can be a significant source of nutrients in areas where livestock is part of the farming systems. To supply 90 kg N/ha from organic sources apply either 7 t/ha of cow dung or 4 t/ha of chicken manure or 5 t/ha of good quality compost to the crop. Fertilizer application should be carried out after weeding so that weeds do not benefit from applied fertilizers. Integrated use of mineral and organic fertilizers should be employed to maximize economic yield and to improve the physical, chemical and biological properties of the soil.
Do not grow maize continuously on the same piece of land for more than two seasons as this practice will deplete soil of major plant nutrient resulting in lower yields. Crop rotation strategies as well as intercropping maize with legumes can be used to maintain soil fertility. Growing cowpea, groundnut and soya bean before maize will add residual nitrogen to the soil, which can then be utilized by maize.