Determination of allelopathic potential of a weed Pluchea lanceolata through a multifaceted approach

Abstract

The allelopathic potential of soils from four sites infested with the weed Pluchea lanceolate (DC.) C.B. Clarke (Asteraceae) was investigated. All sites had similar precipitation, similar crops, and weeds in addition to P. lanceolata. The objectives of this study were threefold: first, variations in the allelopathic effects of P. lanceolata infested soils on growth of three crops; second, soil phenolic content as a result of P. lanceolata infestation; and third, if the chemical characteristics and mycoflora of soils and biotic characteristics of P. lanceolata are responsible for the differences in allelopathic potential. Allelopathic effects of P. lanceolata infested soils were assessed on seedling growth of onion, cucumber, and turnip. Qualitative variation in the soil phenolic content from the four P. lanceolata infested sites was observed. No significant differences in soil mycoflora, soil nutrients, and P. lanceolata biotic characteristics were observed. Growth experiments showed mat crops demonstrated variation in allelopathic response to the soils from the four P. lanceolata infested sites. The present study indicates mat in natural field conditions, allelopathic potential of P. lanceolata varies because of agricultural practices specific to each site. Keywords: allelopathy, Asteraceae, interference, phenolics, soil nutrients, weed.