Maize dominates crop production by smallholder farmers in the Lake Albert Crescent (LAC) zone in Uganda; where 50kgha-1N and 25kgha-1P fertilizers and an inter-row spacing of 75x60cm are adopted. Given the clay soils with high phosphorus fixation capacity, redeveloping appropriate fertilizer combination rates and inter row spacing for the LAC zone is important to enhance maize yields. Evaluation was conducted in two sites in 2014 to establish the appropriate fertilizer combination rates and inter-row spacing for maize in two districts. Treatments included; sole N(urea) at five levels; N+P(triple super phosphate) at six levels, and N+P+K (muriate of potash) at three levels, and inter-row spacing treatments of 75x30cm and 75x60cm set in a split plot design of a randomized complete block design. Maize grain yield increased by 490% with sole N at 120kgha-1N, 644% with 90kgha-1N and 15kgha-1P and 626% with 90kgha-1N+15kgha-1P+10 kgha-1K at on-farm. It increased by 61% with sole N at 90kgha-1N, 125% with 90kgha-1N and 15kgha-1P and by 122% with 90kgha-1N+15kgha-1P+10kgha-1K at on-station, all at an inter row spacing of 75x30cm. Maize yield increases were significantly (p<0.001) higher with 90kgha-1N and 15kgha-1P than with sole N and N+P+K fertilizers, confirming that N and P are the most limiting nutrients for maize productivity. An inter row spacing of 75x30cm and fertilizer combination rates of 90kgha-1N with 15kgha-1P are appropriate in improving maize yields in the zone.
Key Words: Fertilizer combination rates, Maize yield, Inter-row spacing.