Effects of temperature, precipitation and carbon dioxide concentrations on the requirements for crop irrigation water in China under future climate scenarios
Graphical abstract
Irrigation water requirements with temperature-only (T-only), precipitation-only (P-only) and carbon dioxide-only (CO2-only) for (a) maize, (b) rice, (c) soybean and (d) wheat under the representative concentration pathway scenario RCP8.5 in China in the 2010s (2006–2020), 2030s (2021–2040), 2050s (2041–2060), 2070s (2061–2080), and 2090s (2081–2100).
Introduction
Irrigation has a major role in food security and the alleviation of poverty in China. Over 70% of the water consumed in China is used for agricultural irrigation, with irrigation water applied to >75% of crops on >30% of agricultural land (Thomas, 2008; Xiong et al., 2009). As irrigation is the major use of water in agricultural regions, the capacity to supply irrigation water is crucial in the long-term development of water resources and in decision-making about future agricultural production in China.
The irrigation water requirement (IWR) is the amount of water that must be supplied to a crop via irrigation to achieve optimum crop growth, taking into consideration the losses incurred during the transport and application of the irrigation water. Global factors such as climate change [i.e., increasing temperatures, fluctuations in precipitation and increasing concentrations of atmospheric carbon dioxide (CO2)] are placing increasing stress on agricultural systems and drive variations in the IWR (Wang et al., 2014).
A number of studies over the past few decades have quantified the impact of future climate change on irrigation at regional and global scales. Significant increases have been estimated for the long-term IWR as a result of a warming climate and increased evaporative demand (e.g., Fischer et al., 2007; Pfister et al., 2011; Konzmann et al., 2013; Elliott et al., 2014). Increased atmospheric concentrations of CO2 have been shown to directly affect transpiration via both the physiological and structural responses of plants, which tend to reduce their leaf stomatal conductance and thus the rate of evapotranspiration, improving the efficiency of water use by crops (Gerten et al., 2007; Hatfield et al., 2011). Therefore quantifying and analyzing the spatial and temporal characteristics of the regional demand for irrigation water by agriculture is important in developing strategies for water management under the future impacts of climate change and the associated demographic, socioeconomic and technological changes.
Assessments of the geographical distribution of crop water requirements in China are widely available (e.g., Leng and Tang, 2014). However, data on the extent to which variations in temperature, precipitation and atmospheric CO2 concentrations will affect future IWRs for specific crops start later and are fairly sparse. Some studies do not take into account the use of water by specific crops. For example, Thomas (2008) modeled the effects of climate change on irrigation requirements in China with high-resolution gridded climate datasets; but he identified the crops as main, second and third crops according to the cropping system. Some studies take into account the specific field crops without consideration of the effect of CO2 on the use of water by crops. For example, Liu et al. (2009) provided IWRs for 30 different crops estimated using the Food and Agriculture Organization (FAO) Penman–Monteith equation and the crop coefficient method based on meteorological data for the period 1970–2000 from observation stations and statistical data about the stages of crop growth in different areas of China. Cong et al. (2011) reported increases in the IWRs of crops in China due to increases in future temperatures using the FAO Penman–Monteith equation, crop coefficients and the Köppen climate classification system under future emission scenarios.
To improve these methods and to fill some gaps in research, this study applied a standard method of estimating future IWRs (including the crop coefficient approach and the FAO Penman–Monteith equation incorporating the effect of CO2) based on gridded climatic data from 2006 to 2100 simulated by six bias correction and spatial disaggregation climate projections in the fifth phase of the Coupled Model Intercomparison Project (CMIP5) archive under three representative concentration pathway (RCP) scenarios (RCP2.6, RCP4.5 and RCP8.5). The aims of this study were to: (1) explore the long-term temporal and spatial variations in the IWR of major crops (maize, rice, wheat and soybean) in China in the future; (2) conduct an analysis of how the IWR responds to climate change associated with variations in temperature, precipitation and CO2 concentrations; and (3) investigate the dominant climatic factors governing the behavior of the crop-specific IWRs. The results were compared with historical publications to determine the validity and precision of this method. These results may provide reference values for climate adaptation strategies and the sustainable development of agriculture under scenarios of climate warming and water shortages. The method developed in this study may also provide guidance for the scientific research in agro-climatology and the establishment of reasonable agricultural irrigation schemes.
Section snippets
Crop types
Cereal and legume crops—such as maize (Zea mays L.), rice (Oryza sativa L.), wheat (Triticum aestivum L.) and soybean (Glycine max L.)—are cultivated and produced in most cropland areas in China (http://data.stats.gov.cn) (Leff et al., 2004). The majority of the cropland areas are in southern and eastern China in the humid, rainy, monsoon climate zone, although a few are located in the dry area of northwest China. Potential changes in the IWRs for these four crops are important in assessing the
Relative changes in the IWR for different crops
For maize, the IWR decreased over a wide area of the IRB by the 2090s relative to the 2010s under the RCP2.6, RCP4.5 and RCP8.5 scenarios. The relative changes on the national scale were −42.40, −3.78 and −80.14%, respectively (Fig. 2, Fig. 3). The decrease was larger under the RCP8.5 scenario, but a sharp increase also occurred in some western parts of the IRB under the RCP4.5 scenario.
For rice, the IWR showed large increases in the PRB by the 2090s relative to the 2010s under the RCP2.6,
Comparison with similar studies
As per Table 4, this study showed identical or similar results of spatial variations in the IWRs of crops compared with the results reported by Döll (2002), Cong et al. (2011) and Konzmann et al. (2013). This study effectively simulated the decreased IWRs of maize and wheat in IRB and the fluctuant IWR of rice in PRB. And our simulations were closest to the results reported by Konzmann et al. (2013), who quantified global changes in the irrigation requirements of major crop types using the
Conclusions and perspective
This study investigated the effects of future climate change on the IWRs of maize, rice, soybean and wheat in China using the FAO Penman–Monteith equation (incorporating the CO2 effect) and the crop coefficient approach. Substantially different spatiotemporal patterns of the IWR were derived under different RCP scenarios due to the combination of increasing temperatures, regional increases in precipitation and the beneficial effects of CO2 on plants. The regions that will require irrigation
Acknowledgments
The authors are indebted to Jing Ge and Gaopeng Li at the Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, and Yao Li at the College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, for their suggestions. The authors are also grateful to the anonymous referees and the handling editor for the provision of constructive and useful reviews and advice that have led to a substantially improved revised paper. This study was funded
References (65)
Irrigation with saline water: benefits and environmental impact
Agric. Water Manag.
(1999)- et al.
Water resources and water use efficiency in the North China Plain: current status and agronomic management options
Agric. Water Manag.
(2010) - et al.
Sensitivity of groundwater recharge under irrigated agriculture to changes in climate, CO2 concentrations and canopy structure
Agric. Water Manag.
(2010) - et al.
Climate change impacts on irrigation water requirements: effects of mitigation, 1990–2080
Technol. Forecast. Soc. Chang.
(2007) - et al.
Projected water consumption in future global agriculture: scenarios and related impacts
Sci. Total Environ.
(2011) - et al.
Estimation of ET0 with Hargreaves-Samani and FAO-PM temperature methods for a wide range of climates in Iran
Agric. Water Manag.
(2013) - et al.
Estimation of regional irrigation water requirement and water supply risk in the arid region of Northwestern China 1989–2010
Agric. Water Manag.
(2013) - et al.
A method for estimating the direct and climatic effects of rising atmospheric carbon dioxide on growth and yield of crops: part 1. Modification of the EPIC model for climate change analysis
Agric. Syst.
(1992) - et al.
Future climate change, the agricultural water cycle, and agricultural production in China
Agric. Ecosyst. Environ.
(2003) Agricultural irrigation demand under present and future climate scenarios in China
Glob. Planet. Chang.
(2008)
Investing in irrigation: reviewing the past and looking to the future
Agric. Water Manag.
Responses of rice yield, irrigation water requirement and water use efficiency to climate change in China: historical simulation and future projections
Agric. Water Manag.
Winter wheat water requirement and utilization efficiency under simulated climate change conditions: a Penman–Monteith model evaluation
Agric. Water Manag.
Representing water scarcity in future agricultural assessments
Anthropocene
Climate change, water availability and future cereal production in China
Agric. Ecosyst. Environ.
Spatial-temporal precipitation changes (1956–2000) and their implications for agriculture in China
Glob. Planet. Chang.
Spatio-temporal variations in the areas suitable for the cultivation of rice and maize in China under future climate scenarios
Sci. Total Environ.
Standardized Precipitation Evapotranspiration Index is highly correlated with total water storage over China under future climate scenarios
Atmos. Environ.
Crop evapotranspiration: guidelines for computing crop requirements
Worldwide assessment of the Penman–Monteith temperature approach for the estimation of monthly reference evapotranspiration
Theor. Appl. Climatol.
Water supply, water demand and agricultural water scarcity in China: a basin approach
A tool for the evaluation of irrigation water quality in the arid and semi-arid regions
Agronomy
A comprehensive evaluation of precipitation simulations over China based on CMIP5 multimodel ensemble projections
J. Geophys. Res. Atmos.
Crop water demand in China under the SRA1B emissions scenario
Adv. Water Sci.
Water Productivity of Irrigated Crops in Sirsa District, India; Integration of Remote Sensing, Crop and Soil Models and Geographical Information Systems
Regional disparities in the beneficial effects of rising CO2 concentrations on crop water productivity
Nat. Clim. Chang.
Impact of climate change and variability on irrigation requirements: a global perspective
Clim. Chang.
Global modeling of irrigation water requirements
Water Resour. Res.
Constraints and potentials of future irrigation water availability on agricultural production under climate change
Proc. Natl. Acad. Sci. U. S. A.
Irrigation water requirements for seed corn and coffee under potential climate change scenarios
J. Water Clim. Chang.
Land and Water Development Division. CROPWAT Model
Potential future changes in water limitation of the terrestrial biosphere
Clim. Chang.
Cited by (45)
Projecting the impact of climate change and elevated CO<inf>2</inf> concentration on rice irrigation water requirement in China
2024, Science of the Total EnvironmentWastewater irrigation and its impact on crops in major cultivated belt of Rechna Doab, Pakistan
2023, Kuwait Journal of ScienceAnalysis of irrigation demands of rice: Irrigation decision-making needs to consider future rainfall
2023, Agricultural Water ManagementImpacts of meteorological factors and crop area changes on the variations in winter wheat water requirements in the lower reaches of the Yellow River Basin
2023, Agricultural and Forest Meteorology