Growth and yield of maize towards N–P2O5–K2O recommendation in Northern Ghana

A 3-year (2015–2017) field experiment was conducted in Ghana, Nyankpala (09 o 23’ 33.8” N, 001 o 00’ 24.2” W, 169 m asl) to determine fertilizer recommendation for maize ( Zea mays L.) on Ferric Luvisols . Ten N–P 2 O 5 –K 2 O rates were formulated from five levels of N (0, 60, 90, 120, and 150 kg/ha), four levels of P 2 O 5 (0, 30, 60 and 90 kg/ha) and three levels of K 2 O (0, 30 and 60 kg/ha) and tested in 2015 and 2016 cropping seasons. Plots of 5 m × 4.5 m were planted to maize at 75 cm × 40 cm to maturity stages. The maize to nutrient response functions developed after the 2015 trials were: Y = 1.753 + 0.0207 N-0.0001N 2 , at 60 kg/ha P 2 O 5 and 60 kg/ha K 2 O (R 2 = 0.55); Y = 2.153 + 0.0339(P 2 O 5 )-0.0002(P 2 O 5 ) 2 , at 90 kg/ha N and 60 kg/ha K 2 O (R 2 = 0.66); and Y = 2.267 + 0.0292(K 2 O)-0.0002(K 2 O ) 2 , at 90 kg/ha N and 60 kg/ha P (R 2 = 0.78). The 2016 results revealed superior yields and yield parameters for 90-60-60, 90-90-60, 120-60-60, and 150-60-60 kg/ha. The four superior rates and a control (0-0-0) were further evaluated in the 2017 cropping season. The grain yields ranged from 710 kg/ha in the control to 3259 kg/ha under 150-60-60 kg/ha. The economic analysis indicated 90-60-60 kg/ha as the best N–P 2 O 5 –K 2 O rate for higher returns in investment (68.2%). However, further studies could be conducted on farmers’ fields to validate the recommendation.