<div style="text-align: justify;">Depletion of nitrogen and phosphorus in terraced hilly areas of Rwanda has lowered maize (Zea mays L.) production. Trials were carried out in 2017 and 2018 in four-year-old-terraced Lixisols and Acrisols of medium and high altitudes to determine effect of nitrogen and phosphorus fertilizer application rates on maize yields. A factorial arrangement of four levels of nitrogen (0, 60, 120 and 180 kg N ha-1) and phosphorus (0, 40, 80 and 120 kg P2O5 ha-1) in a randomized complete block design with 3 replications, was used. Results showed that combinations of 120 - 180 kg N ha-1 and 80 - 120 kg P2O5 ha-1 resulted in significantly (P &lt; 0.05) higher increases in plant height (45 &ndash; 60 % and 56 &ndash; 70 % over the control), stem collar diameter (63 &ndash; 74 % and 43 % over the control) and grain yields (3 times over the control; i.e. 6.40 &ndash; 6.46 t ha-1 and 6.02 - 6.12 t ha-1) in medium and high altitude sites. The optimum fertilizer rates are 176.6 kg N ha-1 and 96.2 kg P2O5 ha-1 in terraced Lixisols of medium altitude area. Land use needs to adjust fertilizer application to these optimum rates for enhanced maize yields in this area and other regions with similar agro-ecological characteristics. Further studies on integrated effects of N and P fertilizers are recommended.</div>

<div style="text-align: justify;">Effects of Nitrogen and Phosphorus Fertilizer Rates on Maize (<em>Zea mays</em> L.) Growth and Yields in Terraced Lands of Medium and High Altitude Regions of Rwanda</div>

Effects of Nitrogen and Phosphorus Fertilizer Rates on Maize (Zea mays L.) Growth and Yields in Terraced Lands of Medium and High Altitude Regions of Rwanda