Impact of the changing winter wheat sown area on agriculture water footprint in the North China Plain

Introduction

The North China Plain (NCP) is the major winter wheat-producing area in China, accounting for more than 60% of China's total winter wheat sown area. However, the NCP region has one of the world's most severe water shortage problems, and water resources are seen as being over-exploited. Agriculture is the largest water consumer in the NCP, accounting for 60-70% of total water consumption. Groundwater has been the lifeblood of agriculture, especially during the winter wheat sowing period, as surface water is very scarce. Here, we consider the changes in the winter wheat sown area in the NCP since the late 1990s, according to official statistics and the result of our field survey. The main objectives of this study are as follows: 1) analyze the spatial distribution of the water footprint in the NCP; 2) estimate how green and blue water consumption changes with the changes in the sown areas of winter wheat in the NCP; 3) predict future changes in green and blue water consumption for winter wheat in the NCP driven by different land use change and climate change scenarios. Our purpose is to contribute science-based evidence that will enable policies affecting agro-land use change to alleviate water stress problems in the NCP.

Methodology

The China-AEZ model was used in my research to calculate the green and blue water footprint during the winter wheat sown period. Climate indicators in the base period 1981-2010, as well as future period 2011-2100 under A2, A1B, and B2 carbon emission scenarios predicted by the PRECIS model, were the main input of the China-AEZ model. The groundwater intensity index (GI) was used to subdivide blue water consumption (BWC) into blue water from groundwater sources (BWCg) and from surface water sources (BWCs).

Results and Conclusions

1) Across the NCP, the blue water footprint dominates; the green water footprint is dominant in the southern part of the NCP. Sowing winter wheat in the northern NCP is more water-intensive and blue water-intensive. 2) With the shifting of the winter wheat sown area to the southern part of the NCP during 1998-2011, GWC and BWCs increased 1188.17*10⁶t and 370.17*10⁶t, respectively, across the whole NCP, while BWCg decreased 100.92*10⁶t. 3) There is irrigation water conservation in northern NCP, especially in the Hebei Plain, including CSZ 61, 62, and 63; while in the southern NCP and along the Yellow River Basin, especially in CSZ 64, 67, and 81, more irrigation water was consumed in 2011 than in 1998.

Please note these Proceedings have received limited or no review from supervisors and IIASA program directors, and the views and results expressed therein do not necessarily represent IIASA, its National Member Organizations, or other organizations supporting the work.

Last edited: 19 August 2015