Competitive Interactions Between Weeds and Chickpea ('Cicer Arietinum' L.): Towards the Development of an Integrated Weed Management System

Abstract

The production of chickpea ('Cicer arietinum' L.) in the northern grains region of eastern Australia has great potential for breaking grass disease cycles, improving soil nutritional status, and alternating herbicides within crop rotations. However, the susceptibility of chickpea to weed competition has hindered its adoption in rotations. This thesis investigates the agronomic production of chickpea by examining how manipulations of sowing pattern, timing of herbicide applications, and selection of varietal material affect its competitive interaction with weeds. It was found that the manipulation of chickpea sowing pattern from narrow (32 cm rows) to wide (64 cm rows) had no detrimental effect on chickpea yield when grown in competition with varying densities of 'Rapistrum rugosum' (1.) All. (turnip weed) or 'Avena sterilis' ssp. 'ludoviciana' (Durieu) Nyman (wild oat). Increasing the weed (wild oat, turnip weed) density was found to reduce the chickpea yield in a manner best described by a rectangular hyperbolic model. From the model, weed densities of 8 turnip weeds M⁻² or 10 wild oats rn⁻² reduced chickpea yield by more than 50% compared with a weed-free control.