Allelopathic potential of <i>Lantana camara</i> for weed control in cowpea (<i>Vigna unguiculata</i> L. Walp)

Abstract

Smallholder farmers have challenges of weed control and mostly they use cultural control methods because chemical control with herbicides is usually costly. However, <em>Lantana camara </em>L. is known to be allelopathic to other plants hence a worthy candidate for biological control of weeds under cowpea production. A field study was conducted to determine the potential for <em>L. camara</em> to control weeds in cowpea at the University of Zambia Agricultural Experimentation Station. Leaves were harvested from two genotypes of <em>L. camara</em> (G1: Pink-flowered and G2: Orange-flowered genotypes) dried and pulverized to form a powder and applied at different rates (R0C: 0 kg ha^-1, R1: 100 kg ha^-1, R2: 200 kg ha^-1, R3: 400 kg ha^-1) using the following types of application: T0C: No application, T1: broadcasting, T2: incorporation in the soil and T3: spraying of soaked ground <em>L. camara</em>. The research was conducted at the University Of Zambia School Of Agricultural Sciences Field Station. The experiment was arranged in a split split-plot design with three replications. Weed population density and weed weight were reduced the most (38% and 12.5%, respectively) at the highest rate (R3: 400 kg ha^-1) of <em>L. camara </em>application. The cowpea grain yield was higher (<em>P</em>< 0.05) in fields treated with G1 (mean =876.90 kg ha^-1) than for G2 (mean =672.10 kg ha^-1). G1 increased cowpea grain yield by 36.04%. <em>Lantana camara</em> holds great potential to increase food security by reducing losses associated with weeds in cowpea.