Prediction of annual weed seed emergence in garlic (Allium sativum L.) using soil thermal time

• Two annual weed seed emergence pattern in garlic field was studied.
• Model validation performed well in predicting the seedling emergence of both species.
• A. fatua showed lower TT requirements to start emergence after sowing than P. aviculare.
• A. fatua and P. aviculare required 480 and 615 TT for 90% emergence, respectively.
• The model would assist producers to determine the best time to apply a control measure.

Avena fatua L. and Polygonum aviculare L. are two competitive weeds in garlic (Allium sativum L.) fields. Knowledge of the temporal pattern emergence will contribute to optimizing the timing of control measures, thus maximizing efficacy. The development of predictive models can contribute to control measures at early growth stages. The objective of this study was to develop and validate predictive empirical models of emergence for A. fatua and P. aviculare based on thermal time. Cumulative seedling emergence data were obtained during two years from a garlic field and used to develop and validate the models. The relationship between cumulative seedling emergences and cumulative thermal time (TT) under field conditions was analyzed using the Gompertz function. The models accounted for 98% and 96% of the variation observed in A. fatua and P. aviculare, respectively. Model validation performed well in predicting the seedling emergence of both species. According to this model, A. fatua emergence started at 381 TT after sowing and reached 50% and 90% of total emergence at 407 and 478 TT, respectively, with a soil base temperature of 1 °C. P. aviculare started emergence at 410 TT after sowing and reached 50% and 90% of total emergence at 505 and 590 TT, respectively, with a base temperature of 0 °C. Results indicate that these models could be useful as predictive tool contributing to a effective control of A. fatua and P. aviculare populations in garlic crops.