SIMULATION OF SOME PARAMETERS OF PLANT WATER RELATION IN MAIZE
2002, 3 (2) p. 95-104
Investigations on simulation of plant temperature and stomatal resistance in maize by using the microclimate simulation model of Goudriaan (1977) were carried out at Keszthely Agrometeorological Research Station, during the growing season of 2001. The size of plot was 0.5 ha, because of parallel investigations done on the elements of microclimate. To facilitate the validation of the model field observations were measured. Two watering levels, rainfed plots with natural rainfall only, and irrigated plant stand were applied in simulation study. We irrigated the plants by using the amounts of crop water stress index with +drop irrigation system. The limit value for watering was the CWSI >0,25. In summer of 2001 the weather was dry and hot. The lack of water was substituted by 170 mm irrigation water on 4 occasions. To validate the model the root mean square deviation (RMSD) between a number of pairs of simulated and measured microclimate elements was applied. The estimation of plant temperature was very accurate, the error of simulation was below 0.5 degree for noon irrigated plots and 0.3 degree for irrigated ones. The accuracy in stomatal resistance simulation was weaker than that of plant temperature, the error was 5.9 % for nonirrigated, and 21 % for irrigated plots. The estimation of stomatal resistance for irrigated plants need further refinement, but this requires changes in the basic equations of the model.