Effect of nitrogen fertiliser rates and plant density on grain yield of maize
AbstractLow soil fertility has constrained maize production in Sidama district in the Southern region of Ethiopia. The effects of four levels of nitrogen fertiliser (0, 46, 92, 138 kg N ha-1) and four plant populations (44000, 53000, 67000 and 89000 plants ha-1) on grain yield of maize were evaluated over four years (1995-98) at Awassa Research Centre. The experiment was laid out in a randomised complete block design arranged as a complete factorial with three replicates. Effect of N application was dependent on seasonal distribution of precipitation (P<0.01). The mean yields from N fertilised, under favourable and unfavourable rainfall, were 7802 and 5931 kg ha-1, respectively. N fertiliser had a very large effect under erratic rainfall and accounted for 81% of the variations in yield. Both the linear and quadratic responses to N were significant. Fertiliser use efficiency was more for the 46 kg N ha-1. Generally, increased application of N fertiliser resulted in higher yields and accounted for 83 % of the variation. Response to higher plant density was significantly higher when moisture was favourable.
Key Words: Ethiopia, moisture distribution, soil fertility, Zea mays
(African Crop Science Journal 8(3) 2000: 273-282)