Weed control using allelopathic plant species

Abstract

This project is evaluating the effects of allelopathic plant species on a range of weed species that are problematic in Kurdistan. (PhD student: Hadi Aliki)

Description

Allelopathy is a natural approach to weed control which is based on the beneficial or harmful effects of one plant upon another and can involve either cultivated or wild plant species. The allelopathic effect of these plants is produced through chemical compounds from the plant which pass into the soil by a number of methods (Weston, 2005).These compounds with allelopathic potential exist in all plant tissues, including leaves, flowers, fruits, stems, root, rhizomes and seed (Putnam and Tag, 1986).

Many crops such as sorghum, sunflower, alfalfa, barley, clovers, sesame, tobacco, sweet potato, rice, brassica, rye, wheat and oat can release allelopathic compounds and can have a suppression effect on weeds (Miller, 1996; Weston, 1996). Batish et al. (2002) also reported that many weeds themselves can affect crops by releasing allelopathic compounds.  Examples include Canada thistle, cocklebur, common lambsquarters, field bindweed, foxtail sp, Kochia, pigweed, velvetleaf, yellow nutsedge, wild oat and wild mustard. Allelopathic compounds produced by different plants include p-coumaric, syringic, vanillic, p-hydroxbenzoic and protoatechuic acid, scopolin, chlorogenic acid, isochlorogenic acid and a-naphthol (Chou and Lin 1976; Mandava1985).

There are numerous studies which show the beneficial effects of allelopathy.  However, there is little research about using allelopathic plants to control weeds in the Kurdistan region. Research exists in countries near to Iraq such as Iran, Syria, Jordan, Turkey and Saudi Arabia which have a similar environment and species distribution.

1. Identify allelopathic weed suppression from selected crop species.
2. Elucidate allelopathic chemicals responsible for weed suppression.
3. Investigate the effect of environmental factors on the range and quantity of allelopathic chemicals produced.
4. Determine the utility of allelopathic crops and chemicals as a component of integrated weed management strategies.
5. Determine the effect of allelopathic crops in relation to physical and chemical properties of soil on the physiological and morphological characteristics of weeds.