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Sci Total Environ. 2018 Nov 15;642:1-11. doi: 10.1016/j.scitotenv.2018.06.028. Epub 2018 Jun 14.

Effects of water stress on water use efficiency of irrigated and rainfed wheat in the Loess Plateau, China.

Author information

1
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China.
2
Department of Plant and Soil Sciences, College of Agriculture, Food and Environment, University of Kentucky, KY 40506, USA.
3
National Meteorological Center, Beijing 100081, China.
4
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China; College of Resources and Environment, University of Chinese Academy of Science, Beijing 100049, China; School of Life Sciences, University of Technology Sydney, P.O. Box 123, Broadway, NSW 2007, Australia. Electronic address: qiang.yu@uts.edu.au.

Abstract

The Loess Plateau, the largest arid and semi-arid zone in China, has been confronted with more severe water resource pressure and a growing demand for food production under global changes. For developing sustainable agriculture in this region, it is critical to learn spatiotemporal variations in water use efficiency (WUE) of main crops (e.g. winter wheat in this region) under various water management practices. In this study, we classified irrigated and rainfed wheat areas based on MODIS data, and calculated the winter wheat yield by using an improved light use efficiency model. The actual evapotranspiration (ETa) of winter wheat and the evapotranspiration drought index (EDI) were also investigated. Then we mainly examined the synergistic relationship between crop yield, ETa, and WUE, and analyzed the variations in WUE of irrigated and rainfed wheat under water stress during the 2010-2011 growing season. The results suggested that winter wheat in the Loess Plateau was primarily dominated by rainfed wheat. The average yield of irrigated wheat was 3928.4 kg/ha, 22.2% more than that of rainfed wheat. High spatial heterogeneities of harvest index (HI) and maximum light use efficiency (εmax) were found in the Loess Plateau. The ETa of irrigated wheat was 10.2% more than that of rainfed wheat. The ratio of irrigated and rainfed wheat under no water stress was 31.55% and 17.16%, respectively. With increasing water stress, the WUE of rainfed wheat decreased more quickly than that of irrigated wheat. The WUE variations in winter wheat under water stress depended strongly on the synergistic effects of two WUE components (crop yield and ETa) and their response to environmental conditions as well as water management practices (irrigated or rainfed). Our findings enhance our current understanding of the variations in WUE as affected by water stress under various water use conditions in arid and semi-arid areas.

KEYWORDS:

Irrigated and rainfed wheat; Light use efficiency model; MODIS NDVI time series; Water stress; Water use efficiency (WUE)

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