Effects of global climate change on the hydrological cycle and crop growth under heavily irrigated management - A comparison between CMIP5 and CMIP6

Authors: LI, XINLIN - China Agricultural University; TAN, LILI - China Agricultural University; LI, YINGXUAN - China Agricultural University; QI, JUNYU - University Of Maryland; FENG, PUYU - China Agricultural University; LI, BAOGUO - China Agricultural University; LIU, DE LI - Wagga Wagga Agricultural Institute; ZHANG, XUELIANG - China Agricultural University; Marek, Gary; ZHANG, YINGQI - China Agricultural University; LIU, HAIPENG - China Agricultural University; SRINIVASAN, RAGHAVAN - Texas A&M University; CHEN, YONG - China Agricultural University

Submitted to: Computers and Electronics in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2022
Publication Date: 10/11/2022
Citation: Li, X., Tan, L., Li, Y., Qi, J., Feng, P., Li, B., Liu, D., Zhang, X., Marek, G.W., Zhang, Y., Liu, H., Srinivasan, R., Chen, Y. 2022. Effects of global climate change on the hydrological cycle and crop growth under heavily irrigated management - A comparison between CMIP5 and CMIP6. Computers and Electronics in Agriculture. 202. Article 107408. https://doi.org/10.1016/j.compag.2022.107408.
DOI: https://doi.org/10.1016/j.compag.2022.107408

Interpretive Summary: Simulating the effects of projected climate change on agricultural crop production are key for assessing future impacts on irrigation groundwater resources worldwide. Although air temperatures and atmospheric CO2 concentrations are expected to rise in coming decades, their overall impact on crop production and irrigation resources are largely unknown. Simulation modeling using global circulation models may provide insight into potential effects on future irrigation and crop yield. Global Circulation Models (GCMs) are continually evaluated and revised to provide improved climate prediction data. Researchers from China Agricultural University, Wagga Wagga Agricultural Institute (Australia), University of Maryland, Texas A&M University and USDA-ARS Bushland compared simulation results for the Daqing River Basin in China using previously released and newly released climate forecast data using an improved a coupled crop-hydrologic model. Results indicated that although trends for the two climate forecast data were similar, the newer data exhibited greater spatial resolution and lower uncertainty in future scenarios. Projected increases in rainfall may actually support greater wheat and corn yields during the second half of the 21st century. Such information can be used by water policy makers when making decisions about the adequacy of infrastructure to support irrigation.

Technical Abstract: Quantifying the impact of future climate change on the water cycle and crop production at a basin level is essential for water resource management and agricultural production planning. This study compared the GCM projections of CMIP5 and CMIP6 and further used the selected GCMs to quantify the impact of future climate change on the water cycle and crop production in the Daqing River Basin of North China Plain using an improved SWAT model (SWAT-MAD). Taylor’s skill score was used to screen out six groups of GCMs with better simulation performance from 10 pairs of homologous GCMs of CMIP5 and CMIP6. The SWAT-MAD model driven by selected GCMs showed that the simulated changing patterns of CMIP5 and CMIP6 regarding the hydrological cycle were similar. During winter wheat growing season, average actual evapotranspiration (ETa) increased by 3, 3, 4, and 5 percent, respectively, under RCP4.5 2041-2070, SSP2-4.5 2041-2070, RCP4.5 2071-2100, and SSP2-4.5 2071-2100 scenarios. During summer maize growing season, those changes in average ETa were 4, 2, -0.2, and -3 percent. Compared to the historical period (1971-2000), precipitation, air temperatures, and surface runoff could increase, while irrigation could decrease as CO2 concentration and precipitation increased. The dynamic patterns of leaf area index of winter wheat and summer maize indicated that there is a tendency for early maturity and early decay of both crops in the future, and the overall daily total biomass increased with a clear increase in yields. The highest increases in yields of winter wheat and summer maize were 18.9 and 16.7 percent, respectively. This study not only contributes to improvement in the confidence of future projections using CMIP6 GCMs and bolsters our understanding of the relative uncertainty in SSPs and RCPs, but also provides data and theoretical support for water resource utilization and agricultural production decision making in the Daqing River Basin.