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| Experiment on variation characteristics of hydrogen and oxygen stable isotopes of Lycium barbarum in Ningxia under different irrigation conditions |
| TANG Ying, XU Ligang*, WANG Huaibo, BAO Ziyun |
| Ningxia Institute of Water Resources Research, Ningxia, Yinchuan 750021, China |
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Abstract Considering the Lycium barbarum in Ningxia as research object, the rainfall data, root system and stem sample of the Lycium barbarum under different irrigation quotas and precipitations in the experiment filed were collected, then the δ18O and δD values were measured to analyze the variation characteristics of stable isotope in the Lycium barbarum. The IsoSource model was used to calculate soil water utilization efficiency of each potential water sources to the Lycium barbarum. The results show that there is a good linear relationship between δD and δ18O in precipitation and a line regression equation was built for the meteoric water line in the experimental field. The soil moisture content has a ne-gative correlation with the corresponding δD of the Lycium barbarum under different irrigation quotas(20-60 cm), and the δD value decreased with deepening soil layer. The variation pattern of δD in different soil layers was similar to that in 20 cm below 5 mm precipitation, where the maximum δD value was -64.39 ‰. The Lycium barbarum mainly utilizes the water in the surface soil layer(0-20 cm)and middle soil layer(20-40 cm)respectively with utilization efficiencies of 35.2% and 25.1%. The value of δD in 20-60 cm was richer(>-65.20 ‰)when the precipitation was 13.9 mm. The Lycium barbarum can make use of soil water content in 0-60 cm deep soil layer, especially the water utilization efficiencies in 1-20, 20-40 and 40-60 cm layers are 22.4%, 25.3% and 23.2%, respectively. The conclusion can provide a reference for reasonable irrigation of Lycium barbarum in arid regions.
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Received: 11 August 2018
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