Weed emergence under simulated arable and no-till conditions: first year results

No-till management leads to beneficial effects on soil fertility preservation, erosion mitigation and cost reduction. However, weed management strategies should be adapted to no-till field conditions. A field experiment was set up on November 2011 to compare emergence behavior of three weed species (Abutilon theophrasti Medik., Sonchus oleraceus L. and Sorghum halepense L. Pers.) and to evaluate if a single model could be adopted to predict their emergence in arable and no-till managements. Two treatments were performed to simulate conditions of weed seeds in arable (seeds overwinter buried in the soil and are affected by soil disturbance due to spring seedbed preparation) and no-till managements (seeds overwinter on soil surface without any further disturbance). Four 100-seeds replicates were included for each treatment. Seedlings were counted weekly from March 2012. Mean percentages of emerged seedlings were calculated for each species, treatment and their combinations. Emergence dynamics was modeled using a logistic function from which time of 50% relative emergence (t50) was estimated. Factorial ANOVA (P<0.05) identified significant effects of species, treatment and their interaction on percentage and t50 of emergence. Regarding emergence percentage, significant differences were found between treatments for A. theophrasti and S. halepense, but not for S. oleraceus. Moreover, the two treatments of each species presented identical emergence dynamics without any significant difference for emergence t50. These findings may suggest that a single model could be adopted to predict seedling emergence for the three species in arable and no-till systems. However, this experiment has to be replicated to confirm these results under different environmental conditions.