Weed surveys were carried out in two citrus orchards at the National Horticultural Research Institute Ibadan, Nigeria to determine the variations in weed species composition in different citrus orchards. The orchards were organic citrus orchard treated with poultry manure (P.M) at 10, 15, 20t/ha N.P.K., 15t/ha P.M. +0.15t/ha N.P.K. and no fertilizer between 2006 and 2008, and intercropped citrus orchard planted with maize, cassava, pineapple, and mucuna between 1996 and 2008. Weeds were randomly sampled with 1m x 1m quadrat in W pattern between june and September 2009. Result shows that the most dominant weed families in organic citrus orchards were, Asteracaea, and Poaceae, while Serophulariaceae, Poaceae Commelinaceae Asteraceae were dominant in intercropped citrus orchard. Taking Relative Density and Relative Frequency into consideration, the Importance value of weeds were found in the following order, viz, Agerantum conyzoides, (23.35%), Imperata cylindrical (16.29%), and Tridax procumbens (12.20%) in the organic citrus orchard, while Perotis indica (19.87%), Scoparia dulcies (10.38%), Commelina benghalensis (9.57) and Tridax procumbens (9.50) were found in intercropped citrus citrus orchard. The greater the importance value, the more competitive is the weed and weed management required. Also, the Co-efficient of community (CC) 0.46 indicates moderate level of infestation of weeds species. Comparison of these orchards revealed the changes in ecological status of weed which is due to specific competition among them during the growth season
Evaluation of different sources of organic manure on the growth and yield of onion (Allium cepa L) and sweet pepper (Capsium annum L) intercrops.