Effect of climate change on field crop production and greenhouse gas emissions in California's Central Valley

摘要

Predictions of climate change under various emission scenarios is highly uncertain but is expected to affect agricultural crop production in the 21st century. However, we know very little about future changes in specific cropping systems under climatechange in California's Central Valley. Here, we used DAYCENT to simulate changes in yield and fluxes of greenhouse gases under A2 (medium-high) and Bl (low) emission scenarios. In total, 18 climate change predictions for the two scenarios were considered by applying different climate models and downscaling methods. The following crops were selected: alfalfa (hay), cotton, maize, winter wheat, tomato, rice, and sunflower. The simulations suggest that future climate change under the different emission scenarios will lead to a broad range of impacts on crop yields. By 2097, yields under A2 decreased in comparison to the 2009 baseline in the following order: cotton (29%) > sunflower (27%) > wheat (17%) > rice (12%) > tomato (9%) > maize (8%).Yields were between 5% (alfalfa) and 21% (cotton) lower under A2 compared to Bl. Under A2, soil carbon (C) storage tended to decrease under climate change due to a decrease in C inputs to the soil and an increase in soil C decomposition. However, differences in nitrous oxide (N_2O) flux between A2 and Bl were not clear.