Open AccessDependency of parameter values of a crop model on the spatial scale of simulation
Author(s) -
Iizumi Toshichika,
Tanaka Yukiko,
Sakurai Gen,
Ishigooka Yasushi,
Yokozawa Masayuki
Publication year - 2014
Publication title -
journal of advances in modeling earth systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.03
H-Index - 58
ISSN - 1942-2466
DOI - 10.1002/2014ms000311
Subject(s) - scale (ratio) , environmental science , yield (engineering) , crop yield , phenology , crop , atmospheric sciences , growing degree day , cultivar , crop simulation model , mathematics , agricultural engineering , agronomy , geology , geography , biology , materials science , engineering , metallurgy , cartography
Reliable regional‐scale representation of crop growth and yields has been increasingly important in earth system modeling for the simulation of atmosphere‐vegetation‐soil interactions in managed ecosystems. While the parameter values in many crop models are location specific or cultivar specific, the validity of such values for regional simulation is in question. We present the scale dependency of likely parameter values that are related to the responses of growth rate and yield to temperature, using the paddy rice model applied to Japan as an example. For all regions, values of the two parameters that determine the degree of yield response to low temperature (the base temperature for calculating cooling degree days and the curvature factor of spikelet sterility caused by low temperature) appeared to change relative to the grid interval. Two additional parameters (the air temperature at which the developmental rate is half of the maximum rate at the optimum temperature and the value of developmental index at which point the crop becomes sensitive to the photoperiod) showed scale dependency in a limited region, whereas the remaining three parameters that determine the phenological characteristics of a rice cultivar and the technological level show no clear scale dependency. These results indicate the importance of using appropriate parameter values for the spatial scale at which a crop model operates. We recommend avoiding the use of location‐specific or cultivar‐specific parameter values for regional crop simulation, unless a rationale is presented suggesting these values are insensitive to spatial scale.