|Dunan, Claudio - COLORADO STATE UNIVERSITY|
|Westra, P - COLORADO STATE UNIVERSITY|
Submitted to: Weed Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 31, 1996
Publication Date: N/A
Technical Abstract: Developing successsful weed management programs requires predicting the dynamics of weed populations. Different models have been built for this purpose. These models often require an extensive amount of data on weed biology that is not available for most species. We are developing a new approach that requires less information. A population of a weed species is sassumed to have a maximum rate of increase if it is not controlled, a maximum rate of decrease with complete control, and a seasonal pattern of emergence. The change in the population in a given year depends on the total level of control. The model estimates the proportion of the weed population that has emerged by the time of a weed control tactic and the proportion of the emerged population that is contolled so that the total level of control varies with the number, timing and efficacy of weed control tactics. Whether a population increases or decreases and the rate of change depends on the total level of control in a given year. The mode has been validated with data from experiments in which weed populations were studied under different crop rotations, tillage systems, and herbicide use. The model captured the impact of crop sequences and tillage systems.