Prediction of Italian ryegrass (Lolium multiflorum L.) emergence using soil thermal time

Italian ryegrass (Lolium multiflorum L.) is a highly competitive weed widely disseminated worldwide that affects both summer and winter crops. The development of predictive emergence models can contribute to optimizing management. aim this study was develop validate an empirical model based on soil thermal time. For development, cumulative in two locations obtained, the validated with data collected experiment conducted independently. Three commonly used were compared (Gompertz, Logistic, Weibull). relationship between time described best by Gompertz model. predicted start at 300 (TT), reaching 50% 444 TT, 90% 590 TT. Model validation performed well predicting proved be efficient describing its emergence. This potential tool for assisting farmers