Abstract

                                The total biomass produced by the three green gram cultivars viz. Co 4, NARP I and Co GG 89047 from the herbicide applied field experiments at different phenological stages of crop growth were fitted into three mathematical models namely Gompertz, Richard's and Logistic to find out the critical weed competition period and its impact on crop growth. The Gompertz model showed high predictability (R) ranging between 95.6 and 99.9 per cent in estimating the TDMP of cultivars nearer to actual values. Besides the values of Chi-square (X2). RSS, RMSD the Gompertz model showed better goodness of fit to simulate the crop growth in terms of TDMP. Among the cultivars. the Co 4 showed comparatively higher value of R for all models at all weed management system with corresponding low values of X2, RSS and RMSD than other two cultivars. The hand weeding and pre-emergence metolachlor treatments recorded high R values than unweeded control indicating the suppression of weeds on crop growth

Key words : Green gram, weeds, competition period, modeling