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| DOI：10.13522/j.cnki.ggps.2017.11.004 |
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| Calculating Water Footprint of Rice Production Based on Experimental Data |
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WU Nan, ZHENG Yalian, LUAN Yajun, GONG Yan, WANG Ziyang, WU Mengyang
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College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China
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| Abstract: |
| Traditional methods for calculating water footprint (WF) of crop production areusually based on estimation, giving rise to uncertainties. This paper proposed a direct methodto calculate WF based on the data measured from rice growing in lysimeters in attempts to improve its accuracy. The blue-green water footprint (BGWF) of the rice was first calculated from water balance and the gray water footprint (GWF) was calculated using the nitrogen and phosphorus concentrationsmeasured fromall drains. We then applied the methods to four scenarios: frequent and shallow irrigation (FSI), wet irrigation (WI), controlled irrigation (CK) and rain-catching and controlled irrigation (RCCI). The results showed that the BGWF of the paddy field varied with time in increase-decrease – increase-decrease, peaking at jointing-booting stage (J).The BGWF appeared predominantly in the returning green stage (R) and the earlytillering stage (Te) due to fertigation and precipitation. The overallwater footprints changed with time in increase - decrease-increase -decrease over the growth season, higher at early tillering stage. BGWF was higher than GWF during R and Te stages, while the opposite was true during other stages. Overall, the BGWF and GWF were457.3～548.3 mm and 214.3～511.9 mm respectively, affected significantly by how the rice was irrigated (P<0.05). The proposed method for calculating water footprints based on the data measured from the experiment is more accurate and reliable than other methods. |
| Key words: rice; irrigation mode; field scale; water footprint; calculation method |
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