Key points are not available for this paper at this time.
Knowledge of timing and extent of weed emergence before and immediately after crop seedbed preparation is needed to decrease need for preplant herbicides and increase efficacy of postemergence weed control in crops with either mechanical or chemical methods. Such knowledge is important for weeds that infest most crops over a wide area. For these reasons a mechanistic seedling emergence model based solely on soil temperature was developed for common lambsquarters. The model was validated using four sets of field data collected in 1988, 1990, and 1991 near Morris, MN. Agreement of predicted and observed emergence values across all site-years was 0.95 and the coefficient of determination (R 2 ) was 0.98 (P < 0.001). Agreement for individual site-years was 0.96, 1.08, 1.08, and 0.98 and associated R 2 values were 0.99, 0.99, 0.99, and 0.98 (P < 0.001 for each site-year), indicating close agreement between predicted and actual emergence values.
Harvey et al. (Tue,) studied this question.