Growth and Yield Response of Upland Rice (Oryza sativa L.) to Different Nitrogen Fertilization and Weeding Levels
Summary
Weed interference and poor soil fertility are important factors resulting in the poor yield of rice in Nigeria. A 2-year field study was therefore conducted to evaluate the effect of different nitrogen fertilization and weeding levels on growth and yield of upland rice in a forest savannah transition zone of Nigeria. A split-plot design in three replicates was used with three nitrogen fertilization levels (0, 60 and 90 kg ha-1) as the main plot treatments, and four weeding levels (zero weeding, one hoe-weeding, two hoe-weedings and weed-free check) as the subplot treatments. Nitrogen fertilization levels had no significant effect on weed density, biomass and weed control efficacy. However, rice vigour, plant height, number of tillers and leaf area index increased significantly with increasing nitrogen fertilization levels up to 60 kg ha-1 and grain yield up to 90 kg ha-1. Two hoe-weedings increased weed control efficacy similar to the weed-free check better than one hoe-weeding. Rice vigour, tiller number, leaf area index and grain yield increased as number of hoe-weeding also increased. Weed-free check that included four hoe-weedings was not better than two hoe-weedings carried out 3 and 6 weeks after sowing (WAS). The result of this study showed that nitrogen fertilization application at 90 kg ha-1 and two hoe-weedings at 3 and 6 WAS would improve weed control and productivity of upland rice.
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