Impact of climate change on crop water requirements in eastern Canada.

摘要

Crop production is highly dependent upon weather; therefore, future climate change could adversely affect the burgeoning global population. The primary objective of this study was to predict the consequences of climate change on agriculture. Since current climate projections use general circulation models (GCMs) on a global scale, a statistical downscaling model (SDSM) was used to downscale these outputs into a local scale, essential for reliable crop model simulations.;Regarding predicted increases in temperatures and variability in precipitation, the SDSM-HadCM3 A2 scenario forecast the greatest increases, namely ∼3.5 and ∼2.5°C in average monthly maximum and minimum temperatures, respectively, during the growing season, compared to a 1961-1990 base period. Moreover, precipitation events were also predicted to be more frequent (8 to 30%) and intense (10 to 50%) during crop growing months.;With these future climate change scenarios, irrigated peach yield could increase 5 to 20%, since actual tree transpiration reached 0.8 kg/h (compared to a maximum of 0.4 kg/h without irrigation). Furthermore, with irrigation, fruit firmness, the best indicator of ripening and predictor of peach storage potential, is expected to improve by 20% over the current value of 340 kPa.;The most novel aspect of this study was development of the IRM, and its prediction of optimal irrigation needed to sustain or increase crop yield and quality, and concurrently conserve water.;By linking predicted changes in local climate to soil properties and crop characteristics through field and laboratory studies, thresholds of soil moisture content for efficient irrigation scheduling were defined, and an irrigation requirements model (IRM) was developed. Using the IRM, irrigation was triggered when soil moisture was 18 or 24 mm for peaches grown in clay and sandy soils, respectively, and was also triggered at 56 mm for grapes grown in clay soils. It was noteworthy that the IRM reduced irrigation needs by 20 to 25% without affecting yield of peaches (50 to 60 kg/tree).