Weed Population Dynamics In An Irvingia (Irvingia Wombolu Vermeosen) Orchard As Influenced By Fertilizer and Population Density

Field experiment was conducted in an Irvingia (Irvingia wombolu) orchard at National Horticultural Research Institute, Ibadan, to assess the effect Irvingia population density and fertilizer application on weed density, weed biomass and growth of Irvingia wombolu. Three different populations of 7m x 7m, 7m x 6m and 7m x 5m, with plant densities of 204,238 and 285 plants/ha respectively were considered. The experimental design was a 5 x 3 factorial, laid out in randomized complete block design with three replicates. Treatment includes NPK 20:10:10 at 0, 75, 150, 225, and 300 kg/ha and three population densities of 204,238 and 285 plants/ha at spacing of 7m x 7m, 7m x 6m and 7m x 5m respectively. The experimental design was a 5x 3 factorial, laid out in randomized complete block design. Result obtained revealed that highest weed density of 125, 26 and 29 plants/ha were recorded from trees treated with 150, 225 and 75 kg/ha NPK 20:10:10 in populations of 238, 285 and 204 trees/ha respectively. Significantly higher (p<0.05) weed dry weight of 80 g/m2, 115g/m2 and 220 g/m2 was recoreded from trees treated with 150, 225 and 0 kg/ha NPK in populations of 238, 285 and 204 trees/ha respectively. While tallest palnt of 198.5cm, biggest stem girth of 15.8cm and largest canopy cover were obtained from trees with 75 kg/ha Npk in populations 285 and 238 trees/ha respectively. Improvements in the fertility of nutrient-poor soils of the tropics might increase weed pressure and make the development of effective weed management strategies more critical