Water shortage is a limiting factor for agricultural production in China, and climate change will affect agricultural water use. Studying the effects of climate change on crop irrigation requirement (CIR) would help to tackle climate change, from both food security and sustainable water resource use perspectives. This paper applied SDSM (Statistical DownScaling Model) to simulate future meteorological parameters in the Hetao irrigation district (HID) in the time periods 2041-2070 and 2071-2099, and used the Penman-Monteith equation to calculate reference crop evapotranspiration (ET 0 ), which was further used to calculate crop evapotranspiration (ET c ) and crop water requirement (CWR). CWR and predicted future precipitation were used to calculate CIR. The results show that the climate in the HID will become warmer and wetter; ET 0 would would increase by 4% to 7%; ET c and CWR have the same trend as ET 0 , but different crops have different increase rates. CIR would increase because of the coefficient of the increase of CWR and the decrease of effective precipitation. Based on the current growing area, the CIR would increase by 198 × 10 6 to 242 × 10 6 m 3 by the year 2041-2070, and by 342 × 10 6 to 456 × 10 6 m 3 by the years 2071-2099 respectively. Future climate change will bring greater challenges to regional agricultural water use.
Abstract. Fresh water is consumed during agricultural production. With the shortage of
water resources, assessing the water use efficiency is crucial to effectively
manage agricultural water resources. The water footprint is an improved index
for water use evaluation, and it can reflect the quantity and types of water
usage during crop growth. This study aims to establish a method for
calculating the regional-scale water footprint of crop production based on
hydrological processes, and the water footprint is quantified in terms of
blue and green water. This method analyses the water-use process during the
growth of crops, which includes irrigation, precipitation, groundwater,
evapotranspiration, and drainage, and it ensures a more credible evaluation
of water use. As illustrated by the case of the Hetao irrigation
district (HID), China, the water footprint of wheat, corn and sunflowers were
calculated using this method. The results show that canal water loss and
evapotranspiration were responsible for most of the water consumption and
accounted for 47.9 % and 41.8 % of the total consumption, respectively.
The total water footprint of wheat, corn and sunflowers were 1380–2888, 942–1774 and
2095–4855 m3 t−1, respectively, and the blue footprint accounts
for more than 86 %. The spatial distribution pattern of the green, blue and
total water footprints for the three crops demonstrated that higher values
occurred in the eastern part of the HID, which had more precipitation and was
further away from the irrigation gate. This study offers a vital reference
for improving the method used to calculate the crop water footprint.
Water and food safety are two major challenges which the world faces today. Traditional water management focuses on the reduction of water use through improvements in water saving technologies. However, quantitative research is needed to evaluate the effects of changing food consumption patterns on water resources. Here we report the water saving effects of changing diet pattern of the major crops and animal products in mainland China. By using the concepts of water footprint (WF) per weight unit and per calorie unit, provided by 13 primary crop and animal products, the WFs of the 13 agricultural products in each province are compared, and their water/energy conversion efficiencies are analyzed. Then, impacts of different scenarios of changing diet pattern on water consumption were explored. Results show that there are obvious differences between the WF per weight and calorie unit provided by crop and animal products due to the nutritional properties of the agricultural products. Promoting water savings from the food consumption side could give a positive feedback on water consumption. Scenario analysis of adjustments to the diet pattern proves that it is potentially feasible to reach the objective of alleviating stress on water resources while guaranteeing nutritional value of the residents.
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