| 摘 要： |
Accurately partitioning evapotranspiration (ET) remains one of the key research gaps in agro-ecosystem water research. The interaction of shallow groundwater with winter wheat increased the complexity of ET partitioning. Here we proposed a cutting method to partition ET into soil evaporation (E) and transpiration (T). Field multiple lysimeter experiments under 4 different watertable conditions were conducted at the Yucheng Experimental Station to investigate the partitioning of ET for winter wheat under shallow groundwater. Results showed that the cutting method is applicable and could obtain reasonable ratio of T to ET for crop land of winter wheat. Moreover, the T/ET could be generalized into a curve for representing the ratio of T to ET (i.e. K=T/ET) at the mid-and late-season stages of winter wheat. The maximum value of generalized T/ET curve (K-max) increased with the increase of groundwater table depth (DTW), and was 0.651, 0.768, 0.771 and 0.869 for the depth of 0.4 m, 0.7 m, 1.1 m and 1.5 m, respectively. The higher transpiration proportion corresponded to the higher yield of winter wheat, which indicated that increased groundwater depth was benefit to enhance the groundwater consumption by transpiration and hence yield when watertable depth was within 1.5 m. Moreover, the lower evaporation proportion might lower the soil salinization risk due to less soil evaporation. It is important for the understanding of the interaction between evapotranspiration components of crop with shallow groundwater and the sustainable management in the lower reach of the Yellow River Basin. |
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