Crop models efficiency and performance under elevated atmospheric CO2

Radiation, water and CO2 are three major resources requirement for crops growth and development and within a wide range, increasing each of them would increase the biosphere productivity. Higher usage of fossil fuels is increasing the atmospheric CO2 and according to known crop physiological functions, such conditions should increase the crops production. However there is a possibility that these functions forced to modify as well due to such a change in atmosphere. In order to realize such a change, robust models are required which in turn demands high quality data and complete test of the models. Most climate change studies benefit from crop models however, all models are structured and developed based on current conditions. Our objectives in this study are verification of two crop models for such a possible future climate change and to find whether there are any required modifications for these crop models. Required data for this study were obtained from two international studies on rice plant under FACE experiment in Japan and on peanut crop in USA. Rice experiment included the effects of nitrogen and elevated CO2 and peanut experiment was looking for the effects of CO2 and temperature. Observed data were employed within CSM-DSSAT for peanut and Oryza2000 model for rice plant. The results showed that both models wrongly simulated the magnitude and direction of crops responses mostly for interaction of CO2 and nitrogen and/or temperature which indicated the requirement of modification of some relationships in the crop models in order to be used for any future recommendation under climate change.