Author
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McMaster, Gregory |
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Submitted to: Biological Systems Simulation Group Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 1/22/2001 Publication Date: 3/26/2001 Citation: Mcmaster, G.S. 2001. Modeling crop and rangeland canopy structure and dynamics. Biological Systems Simulation Group Proceedings. March 26, 2001. Interpretive Summary: Improving our ability to predict production and yield will require better representation of canopy developmental processes, and enhancing the efficacy of management practices (e.g., pesticide, fertilizer, irrigation, grazing) and simulating crop responses to extreme events (e.g., hail, frost) will necessitate more precise and detailed phenological models. Most crop, and essentially all rangeland, models are energy- or carbon-driven, where biomass is produced based on solar radiation captured by the plant via some function of LAI and canopy light extinction coefficients. Assimilates are usually partitioned to leaf, stem, seeds, and root components, with partitioning coefficients changed based on simple phenological growth stages. The poor morphological representation of canopy structure and dynamics in rangeland models reflects the lack of developmental research on rangeland plants. Fortunately, the numerous developmental studies since the 1960s on various crops has provided opportunities to better simulate canopy structure and dynamics in crop models. Further, general developmental principles we have learned can be applied to rangeland plants even though species-specific data may be lacking. Despite opportunities to include developmental principles in agricultural models, only a few models such as SHOOTGRO, ModWHT, and SIRIUS have incorporated many of the concepts. The developmentally-driven models provide alternatives to the carbon-based models. Technical Abstract: Improving our ability to predict production and yield will require better representation of canopy developmental processes, and enhancing the efficacy of management practices (e.g., pesticide, fertilizer, irrigation, grazing) and simulating crop responses to extreme events (e.g., hail, frost) will necessitate more precise and detailed phenological models. Most crop, and essentially all rangeland, models are energy- or carbon-driven, where biomass is produced based on solar radiation captured by the plant via some function of LAI and canopy light extinction coefficients. Assimilates are usually partitioned to leaf, stem, seeds, and root components, with partitioning coefficients changed based on simple phenological growth stages. The poor morphological representation of canopy structure and dynamics in rangeland models reflects the lack of developmental research on rangeland plants. Fortunately, the numerous developmental studies since the 1960s on various crops has provided opportunities to better simulate canopy structure and dynamics in crop models. Further, general developmental principles we have learned can be applied to rangeland plants even though species-specific data may be lacking. Despite opportunities to include developmental principles in agricultural models, only a few models such as SHOOTGRO, ModWHT, and SIRIUS have incorporated many of the concepts. The developmentally-driven models provide alternatives to the carbon-based models. |
