| 其他摘要 | Water resources management in irrigation districts is important to ensure food security. The current water resources
management in China focuses on underground water and surface water (i.e. blue water), and precipitation (green water).
However, most studies are on large scale such as global or basin scales and few are on irrigation district scale. The aim of this
paper was to quantify and evaluate the consumption of different types of water resources in the irrigation district by the
concept of water footprint (WF). The maize and wheat production in the Baojixia Irrigation District of Shaanxi in China from
2008 to 2017 were selected as the case study. One hydrological station and two weather stations were included in the study
area. Data of runoff, precipitation irrigation and soil-related physical properties were collected. A regional distributed
hydrological model (Soil and Water Assessment Tool, SWAT) based on the hydrological cycle was established. The model was
constructed by coupling with the soil water balance model and considering the water delivery losses of the irrigation canals.
The blue and green water resources and WFs of crop production were quantified. The variability of the annual WFs of crops
during the study period was analyzed, and the WFs of crops on daily and monthly scales were also analyzed in three typical
years (dry, normal, wet). The runoff data was used to validate the SWAT model, and the MOD16A2GF Version 6
Evapotranspiration product (MOD 16) at a 500 m pixel resolution was used to verify the evapotranspiration simulation results.
Then, the change of WF was analyzed. The results showed that the model could simulate well the runoff with the values of R 2
of 0.74, Nash Efficiency Coefficient (NSE) of 0.69 during the calibration period. By validation, the model was still well and
both the values of R 2 and NSE were 0.51. It indicates that the model established in this study could accurately simulate the
hydrological process in irrigation districts. During the period from 2008 to 2017, the blue and green water resources in
Baojixia Irrigation District increased on the whole. The multi-year average blue water resources in Yangling was the highest
but the multi-year average green water resources in Jingyang was the lowest. The multi-year average total WF values of maize
and wheat (including the blue WF of irrigation delivery losses) were 573 and 779 m 3 /t, respectively, showing an overall rising
trend. The fluctuations of total WFs were mostly affected by the green WF. The green WF of crop production was higher at the
jointing and filling stages and lower at the maturing stage. The WFs of crop production were fluctuated the most on the daily
scale and the fluctuation decreased gradually from month scale to annual scale. The fluctuations of the green and blue WFs of
wheat were the largest in the dry year. Although the irrigation water in the dry year was lower than the normal and wet years,
the unit maize yield and the unit wheat yield were the highest and the total WF values of maize and wheat were the lowest.
This study can provide valuable information for crop production and management in irrigation districts.. |
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