Allelothic Effects of Some Weeds on the Germination of Selected Seeds of Crops Grown In Akwaibom State Nigeria (Published)
In this work, a laboratory and polypot experiments were conducted to study the effects of water extracts of the tops and roots, and the decomposing mulches of the tops, of six (6) dominant weeds at the Teaching and Research Farms of the AkwaIbom State University, ObioAkpa Campus and adjoining areas, on the germination of seeds of six (6) most commonly grown seed crops. The weeds were Apiliaafricana, Emiliasonchifolia, Crotolariaretusa, Chromolaenaodorata, Panicum maximum, and Cyperusesculentus; the test crops were Zea mays, Citrullus vulgaris,Abelmoschusesculentus, Vignaunguiculata, Glycine soja, and Arachis hypogea. 500g of finely chopped tops and roots of each weed was extracted with 1litre of distilled water and applied to seeds in petri dishes after standing for 24hours. Finely chopped tops of each weed were also applied to 1.0kg of heat-sterilized soil in planting polybags as mulches at an equivalence of 0, 2.0, 4.0, 8.0 and 12.0 Mg ha_1.These were watered twice (2) daily and incubation for 48hours before planting of seeds. Germination counts (%) of seeds in petri dishes and seedlings emergence counts (%) from polybags were arranged for use with the randomized complete block design (RCBD) in 3 replications. Both the water extract and the decomposing mulches of tops of all the test weeds significantly (p<.05) inhibited the germination of all test seeds to varying degrees. Cyperusesculentus showed the highest inhibitory effect.