A mechanistic model was constructed for common ragweed growth and development based on the generic plant model CROPSIM. Adaptations were made to CROPSIM's growth and development subroutines to enable common ragweed growth to be simulated. Data from field studies using a single-source common ragweed grown in monoculture and from the literature were used to parameterize the model. The influences of varying environmental conditions across years, densities, and emergence timing on leaf number, leaf area, leaf weight, height, and biomass accumulation were taken into account by the model. Deviations between simulated and measured values generally fell within a relatively narrow range. Deviations outside this range tended to be associated with common ragweed growth shortly after emergence, particularly during temperature and moisture extremes. Future versions of the CROPSIM model may need to include more detailed algorithms for upper soil surface layer temperature and moisture conditions and improved germination and emergence algorithms to reduce these deviations.
Nomenclature: Common ragweed, Ambrosia artemisiifolia L. AMBEL.