Simulation in maize–water relations: a case study for continental climate (Hungary)

Abstract

AbstractLocal consequences of the global climate change in the Carpathian Basin were followed on the basis of simulated stomatal resistances. The Crop Microclimate Simulation Model of Goudriaan was applied in our study. The expected weather, plant and soil modifications were based on long‐term observations during the time period 1961–1990 in the Keszthely area (Hungary, N 46°44′, E 17°14′; altitude 112 m). Besides application of the A2 and B2 SRES scenarios, the impact of extreme hot days was also included in the study. This was necessary as these events have recently occurred more and more frequently. Demonstration of weather scenarios with relatively high warming rates was made possible by the high resolution of the model, simulating even daily changes. The stomatal resistance significantly increased in all scenarios, as was indeed experienced in the last decade (1997–2006). A twofold increase in CO2 concentration approximately halves stomatal openings even under unchanged weather conditions. This can be considered as an advantageous side effect of the global climate change on the plant's water balance, important in continental climate because of scarce precipitation. In Scenarios A2 and B2, increases in resistance were close to the effect of doubled CO2 concentration. Surprisingly, the effect of an increase in the number of extreme hot days on stomatal resistance was moderate, below than what might have been expected. The common impact of the environmental and biological factors on stomatal resistance was realized using normalized leaf area indices, where the highest increases were predicted by using the hottest and driest scenario. Moderate changes in water loss and photosynthesis indicated a certain amount of available soil moisture reserve even in the extreme weather situations in July, at Keszthely. Decrease in carbon assimilation can occur in days with extreme temperatures. Our scenarios do not include significant precipitation decline because of forecast uncertainties. A significant precipitation decrease would fundamentally reshape our results, so we do not propose to extend our conclusions in the case of significant modification in rainfall amount or distribution. Copyright © 2010 John Wiley & Sons, Ltd.