The Response of Hybrid Maize (Zea mays) to N and P Fertilizers on Nitisols of Yeki District, Sheka Zone

Low soil fertility, particularly nitrogen(N)and Phosphorus(P) are among the most yield-limiting nutrients in Ethiopia. Due to blanket NP application at the national level, the response of hybrid maize in Ethiopia is inconsistent and not satisfactory. Hence, a field experiment was initiated to investigate the response of hybrid maize (Zea mays L.) to the application of N and P fertilizer rates and their use efficiency on Nitososl. The study comprised two sets of experiments set I had seven levels of N each with30 kg P ha-1(0, 23, 46, 69, 92, 115 and 138 kg N ha-1) while set II had seven levels of phosphorus each with 92 kg N ha-1(0, 10, 20, 30, 40, 50, and 60 kg P ha-1). Both sets of experiments were replicated in two locations. The treatments were laid out separately in a randomized complete block design with four replications. Results showed that N and P rates of application significantly influenced yield and yield components, uptake and nutrient use efficiency. Generally, N and P use efficiency decreased with increased N and P fertilizer rates. Application of NP significantly increased the number of Kernels Cob-1, 1000-kernel weight, and above-ground dry biomass by at both locations. The maximum maize grain yield of 8093 kg ha-1at Tepi and 8158 kg ha-1at Addis Alem were obtained from 92kg N ha-1and 69kg N ha-1, respectively. The maximum grain yields of 8918kg ha-1at Tepi and 8298 kg ha-1at Addis Alem were produced by the application of 40kg Pha-1for both sites. Applications of 69kg Nha-1 at both sites, and 30 and 40 kg P ha-1were found to be most profitable rates at Addis Alem and Tepi, respectively.