Author
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PAN, X - CROP SICIENCES UOFI URB |
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BEGONIA, G - JACKSON STATE UNI MS |
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Hesketh, John |
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Submitted to: Crop Simulation Workshop Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 4/11/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: The seasonal dynamics of the physiology and structure of the crop-weed leaf area index (LAI) are important in controlling crop photosynthesis, evapotranspiration, rainfall interception, soil erosion and crop-weed competition, as well how pure stands or species mixtures will respond to climate change. Following H.J.W. Mutsaers' impressive KUTUN' modeling effort (Annu. Bot. 51: 503-529, 1983a,b) we measured leaf appearance, expansion and senescence rates, along with internode extension rates, for mainstems and branches in four cotton cultivars, two soybean cultivars, corn, tomato, okra, zucchini, bean, sunflower, velvetleaf, jimsonweed, cocklebur, three morningglory species, pigweed, lambsquarter, black nightshade and foxtail. Rates of the appearance of unfolded and fully expanded leaves, as well as new and fully extended internodes, were derived from plots of areas and lengths vs. accumulated degree days calculated from the appropriate base temperatures. Earlier data of Begonia et al. were also plotted vs. accumulated degree days to obtain coefficients for different genotypes and growing conditions. There were branching differences among cotton cultivars as well as the earlier reported leaf senescence differences among corn and soybean cultivars and growing conditions. During the rapid growth phase in the morningglory species, internodes extended before young leaves expanded. These studies will be extended to other species; models for leaf and internode phenology will be developed further, based upon the ongoing modeling effort at the location. Data are available upon request. |
