Change of winter wheat planting area and its impacts on groundwater depletion in the North China Plain

Abstract

The North China Plain is one of the most water-stressed areas in China. Irrigation of winter wheat mainly utilizes groundwater resources, which has resulted in severe environmental problems. Accurate estimation of crop water consumption and net irrigation water consumption is crucial to guarantee the management of agricultural water resources. An actual crop evapotranspiration (ET) estimation model was proposed, by combining FAO Penman-Monteith method with remote sensing data. The planting area of winter wheat has a significant impact on water consumption; therefore, the planting area was also retrieved. The estimated ET showed good agreement with field-observed ET at four stations. The average relative bias and root mean square error (RMSE) for ET estimation were-2.2% and 25.5 mm, respectively. The results showed the planting area and water consumption of winter wheat had a decreasing trend in the Northern Hebei Plain (N-HBP) and Southern Hebei Plain (S-HBP). Moreover, in these two regions, there was a significant negative correlation between accumulated net irrigation water consumption and groundwater table. The total net irrigation water consumption in the N-HBP and S-HBP accounted for 12.9×10 9 m 3 and 31.9×10 9 m 3 during 2001-2016, respectively. Before and after 2001, the decline rate of groundwater table had a decreasing trend, as did the planting area of winter wheat in the N-HBP and S-HBP. The decrease of winter wheat planting area alleviated the decline of groundwater table in these two regions while the total net irrigation water consumption was both up to 28.5×10 9 m 3 during 2001-2016 in the Northwestern Shandong Plain (NW-SDP) and Northern Henan Plain (N-HNP). In these two regions, there was no significant correlation between accumulated net irrigation water consumption and groundwater table. The Yellow River was able to supply irrigation and the groundwater table had no significant declining trend.

Effect of deficit irrigation scheduling and planting pattern on leaf water status and radiation use efficiency of winter wheat

“…The North China Plain (NCP) is one of the main winter wheat‐producing areas. However, it has a severe shortage of water resources, and the growth and yield of winter wheat depend mainly on irrigation (Wu et al., 2019; Zhou et al., 2018). The rainfall in the NCP generally does not exceed 200 mm in which most rainfalls mainly falls from July to September and water deficit mainly occurred in the winter wheat growing season (October to June), whereas total evapotranspiration of winter wheat is approximately 400–500 mm (Liu et al., 2011).…”

Mapping the Dynamics of Winter Wheat in the North China Plain from Dense Landsat Time Series (1999 to 2019)

“…In fact, heat stress can severely affect the wheat's growing season and yield [48], so farmers would be forced to change the future cropping types to plant crop types having a higher resilience to warming in order to mitigate economic losses. The availability of water (rainfall pattern, river runoff, irrigation) could be another factor controlling changes in winter wheat planting and the cropping systems [49]. Although suffering from these different adverse impacts of climate change and water availability, this study suggests that winter wheat planting is steadily increasing in the NCP, mitigating the increased demand from a rapidly growing population and reducing the dependency on grain import.…”

Water scarcity will constrain the formation of a world-class megalopolis in North China

“…Instead of winter wheat, crops that consume less water, such as spring maize, summer maize, peanuts, cotton, or various cereals are encouraged to reduce the amount of water use. By applying this crop system replacement, each hectare of land can save 2700-3000 m 3 of water 57 . Given the planting area of winter wheat in Hebei was 2.35 million hectares in 2018 58 , this practice would at least bring about a water use reduction of 6.34 billion m 3 ,~50% of Hebei's total agricultural water use.…”