Critical Period for Weed Control of Chickpea in a Semi-Arid Region

Abstract

Field studies were conducted to determine the critical period of weed control in chickpea (Cicer arietinum L.) cv. ‘Jam’. The treatments consisted of two different periods of weed interference and weed control. Weed interference and weed-free treatments were set up after the crop emergence. Beginning of CPWC was determined by allowing weeds to compete or were kept weed-free at 2 weekly intervals for 2 (weed-free control) to 12 weeks after emergence (WAE). The Gompertz and logistic equations were fitted to relative yield and total dry matter representing the critical weed-free and the critical time of weed removal, respectively. Results indicated that Crop yield, total dry matter, 100 seed weight, number of pod in plant and number of seed in plant declined steadily as the duration of weed competition increased, indicating weed infested conditions for the entire growing season led to 76.4-85.8% and 78.5-85.7% reduction in chickpea dry matter and seed yield compared with full-season weed-free treatments. Also, the major weeds in experiment were Stachys byzantine, Tragopogon dubius, Gypsophila pilosa and Euphorbia helioscpia. To prevent >10% yield and total dry matter loss, the maximum time weeds could be allowed to grow after crop emergence were 43 and 36 DAE respectively and Also, critical period for weed control at 5 % yield and total dry matter loss was 36-60 DAE and 26-71 DAE. But critical period at 2.5 % yield and total dry matter loss was widespreader than other loss level. These results suggested that weed control upgraded all of agronomical traits of chickpea especially seed yield and to minimizing loss level of yield removal weeds must be done at 19-80 DAE.