Potential impacts of climate change on carbon dynamics in a rain-fed agro-ecosystem on the Loess Plateau of China

Linjing Qiu; Mingde Hao; Yiping Wu

doi:10.1016/j.scitotenv.2016.10.178

Potential impacts of climate change on carbon dynamics in a rain-fed agro-ecosystem on the Loess Plateau of China

Sci Total Environ. 2017 Jan 15:577:267-278. doi: 10.1016/j.scitotenv.2016.10.178. Epub 2016 Nov 6.

Authors

Linjing Qiu¹, Mingde Hao², Yiping Wu³

Affiliations

¹ Department of Earth and Environmental Science, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
² Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China.
³ Department of Earth and Environmental Science, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China. Electronic address: rocky.ypwu@gmail.com.

PMID: 27829504
DOI: 10.1016/j.scitotenv.2016.10.178

Abstract

Although many studies have been conducted on crop yield in rain-fed agriculture, the possible impacts of climate change on the carbon (C) dynamics of rain-fed rotation systems, particularly their direction and magnitude at the long-term scale, are still poorly understood. In this study, the sensitivity of C dynamics of a typical rotation system to elevated CO₂ and changed temperature and precipitation were first tested using the CENTURY model, based on data collected from a 30-year field experiment of a corn-wheat-wheat-millet (CWWM) rotation system in the tableland of the Loess Plateau. The possible responses of crop biomass C and soil organic C (SOC) accumulation were then evaluated under scenarios representing the Representative Concentration Pathways (RCPs) 4.5 and 8.5. The results indicated that elevated CO₂ and increased precipitation exerted positive effect on biomass C in CWWM rotation system, while increasing the temperature by 1°C, 2°C and 4°C had negative effects on biomass C due to opposite responses of corn and winter wheat to warming. SOC accumulation was enhanced by increased CO₂ concentration and precipitation but impaired by increased temperature. Under future RCP scenarios with dynamic CO₂, the biomass C of corn exhibited decrease during the period of 2046-2075 under RCP4.5 and the period of 2016-2075 under RCP8.5 due to reduced precipitation and a warmer climate. In contrast, winter wheat would benefit from increased CO₂ and temperature and was projected to have larger biomass C under both RCP scenarios. Although the climate condition had large differences between RCP4.5 and RCP8.5, the projected SOC had similar trends under two scenarios due to CO₂ fertilizer effect and precipitation fluctuation. These results implied that crop biomass C and SOC accumulation in a warmer environment are strongly related to precipitation, and increase in field water storage should be emphasized in coping with future climate.

Keywords: Biomass C; CENTURY; Rain-fed rotation system; SOC.