modeling leaf area index (lai) extension of winter wheat as a function of moisture condition

the swleww computer model (soil water leaf extension of winter wheat) was developed in order to simulate the daily extension of winter wheat (triticum aestivum l. cv.ghods) leaf area as a function of soil moisture stress. the model consists of two main components: (1) the previously developed sw a tre (soil water and actual transpiration rate extended) program for simulating the soil water budget and (2) the leww (leaf area extension of winter wheat) program which was established for simulating the time variation of the lai. both programs operating simultaneously are linked at the end of each day. swleww model was tested using data of winter wheat monitored on an experimental field in karadj (iran), on a soil belonging to the mazraeh soil serie , (xerochreptic calciorthids, fine loamy mixed, thermic). close agreement was observed between measured and simulated leaf area extension. this implies predictive use of the model for simulating the leaf area extension of winter wheat as a function of soil moisture stress in the area.