Allelopathic Behaviour of Cyperus Rotundus L. On Both CHORCHORUS OLITORIUS (BROAD LEAVED WEED) AND ECHINOCHLOA CRUS-GALLI (GRASSY WEED) ASSOCIATED WITH SOYBEAN

Abstract

Allelopathic Behaviour ofCyperus RotundusL. On BothCHORCHORUS OLITORIUS(BROAD LEAVED WEED) ANDECHINOCHLOA CRUS-GALLI(GRASSY WEED) ASSOCIATED WITH SOYBEANPurple nutsedge (Cyperus rotundus) foliage and tubers were tested for allelopathic potential against the following weeds; juteChorchorus olitorius(broad leaved weed), and barnyard grassEchinochloa crus-galli(grassy weed) associated with soybean. In the greenhouse, during 2008 and 2009, foliage and tubers ofC. rotunduswere mixed with soil surface at 20, 40, 60 and 80 g/kg.C. rotundusnegatively affected those of jute and barnyard grass particularly at 80 g. Jute was more susceptible to allelopathy byC. rotundusthan barnyard grass. Inhibition in weed dry matter was higher with tuber than foliage residues. Tuber residues reduced the dry weight of jute and barnyard grass by 85.96% of the control and by 58.28% with 80 g, respectively. On the other hand, soybean growth and yield showed a high significant increase compared with unweeded pots. A high-performance liquid chromatography analysis showed thatC. rotundusfoliage contained the following phenolic acids: caffeic, ferulic, coumaric, benzoic, vanelic, chlorogenic and cinnamic. Tubers contained hydroxybenzoic, caffeic, ferulic, vanelic and chlorogenic.