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| DOI：10.13522/j.cnki.ggps.2017.0399 |
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| Impact of Water Stress Occurring at Different Growth Stages on Water Consumption and Water Use Efficiency of Summer Soybean |
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HOU Zhiqiang, JIANG Shangming, JIN Juliang, YUAN Hongwei
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School of Civil Engineering, Hefei University of Technology, Hefei 230009, China; Institute of Water Resources and Environmental Systems Engineering, Hefei University of Technology, Hefei 230009, China; Key Laboratory of Water Conservancy and Water Resources of Anhui Province, Water Resources Research Institute of Anhui Province and Huaihe River Commission, Ministry of Water Resources, Bengbu 233000, China
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| Abstract: |
| 【Objective】The purpose of this paper is to examine water consumption and water use efficiency of summer soybean in response to water stress occurring at different growth stages in attempts to provide guidance to ameliorate yield reduction caused by drought. 【Method】 Pot experiments were conducted in 2015 and 2016 by adjusting soil moisture content at different growth stages. We considered nine water treatments: slight and severe water stress occurring at flowering-podding stage, pod-filling stage, branching stage and seedling stage respectively; and the control was no water stress (CK). For each treatment, we measured and calculated the water consumption and water use efficiency (WUE). 【Result】 Water stress reduced water consumption, and the reduction increased with the stress level. Taking the experiment in 2015 as an example. Compared with the CK, a slight water stress at seedling stage, branch stage, flower-podding stage and pod-filling stage reduced water consumption by 35.60%, 34.89%, 35.39%, 38.35% respectively; while a severe water stress occurring at these stages resulted in a reduction in water consumption by 62.01%, 69.19%, 57.83% and 83.50% respectively. In all treatments, including CK, the water consumption changed with growth stage in the order flowering- podding stage>pod-filling stage>branching stage >seedling stage, and the daily water consumption at pod-filling stage was the lowest under severe drought. The average yield loss caused by drought occurring at the four stages was in the order flower-podding stage>pod-filling stage>branching stage>seedling stage. Taking the experiment in 2016 as an example; the WUE under a severe drought happening at seedling stage, branching stage, flower-podding stage and pod-filling stage reduced by 4.74%, 13.01%, 35.90%, and 18.46% respectively, compared to those under a slight drought, indicating that the WUE decreased with increasing water stress level. It was also found that the impact of drought on WUE depended on the stage during which the drought occurred, and the impact of drought at seedling and branching stages was less significant than drought occurring at flowering-podding stage. 【Conclusion】 The effect of water stress occurring at different growth stages has noticeable impact on water consumption and WUE of the summer soybean. Flower-podding and pod-filling stages are critical stages in terms of water demand, and keeping sufficient water supply at these two stages is thus essential to ensure yield. Meanwhile, imposing an appropriate water stress at seedling and branching stages do not give rise to yield reduction and can be used as water-saving technique. |
| Key words: water consumption; yield; water use efficiency; drought stress; summer soybean; Huaibei plain |
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