mechanistic models_lettuce by ekaputragunartha



I Gde Ekaputra Gunartha, 1995.-- MECHANISTIC MODELS FOR LETTUCE
GROWTH, (i – xix; 196 pages; Appendices: A1 – A85)

       This study concentrates on the biometrical aspects of numerical integration
when used as a predictive mechanism for plant growth.

       It considers further the Sweeney model for lettuce growth, developed in the
UK in a controlled environment but used in this study for both Australian glasshouse
and field data.

       We develop exact and approximate formulae for the relative error involved in
using the Euler method of numerical integration.         We recommend that the more
accurate Runge-Kutta method be used.

       We conduct four experiments to validate some of the assumptions of the
Sweeney model. On the basis of these experiments, we suggest a modified Sweeney
model and demonstrate its performance.

       We propose two other mechanistic models.

       The first, SIMPLEGROW, is based on a Runge-Kutta logistic prediction,
has just one parameter which is modified by daily mean temperature.

       The second, LETGROW, increases the dry weight of a lettuce plant on one
day by some amount which is modified by the plant’s stage of development, by daily
mean temperature and by daily total light intensity.

       All three models perform to some degree of success.

®Department   of Crop Sciences, Faculty of Agriculture                     Page 1/1
 The University of Sydney, Sydney, AUSTRALIA (1995)

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