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| DOI：10.13522/j.cnki.ggps.20180468 |
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| Response in Growth, Quality and Water Consumption of Greenhouse Tomato to Change in Matric Potential at 20 cm below the Emitter of Drip Irrigation |
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WAN Shuqin, YAN Zhenkun, KANG Yuehu, YUAN Baozhong, JIAO Yanping, Guo Jun
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1. Hebei Engineering Research Center for Agricultural Water Saving\Hebei Provincial Academy of Water Resources,Shijiazhuang 050057, China; 2. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; 3. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; 4. College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; 5. Agricultural Office of Tuanbo Town, Jinghai County, Tianjin 301636, China
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| Abstract: |
| 【Objective】Irrigation schedule needs to know the spatiotemporal dynamics of soil moisture in root zone. The objective of this paper is to investigate the feasibility of using matric potential measured at 20 cm below the drip emitter as a proxy for soil moisture in the root zone to schedule irrigation. 【Method】 The experiment was conducted in a greenhouse and the model plant was tomato. We compared seven matric potential (SMP) thresholds in that whenever the measured soil matric potential dropped below them, drip irrigation was resumed. The values of the SMP thresholds varied from flowering and fruit-setting stage to fruiting stage, and the seven combinations (flowering and fruit-setting stage /fruiting stage) were -15 kPa/-15 kPa (S1), -15 kPa/-30 kPa (S2),-15 kPa/-45 kPa (S3), -25 kPa/-25 kPa (S4), -30 kPa/-15 kPa (S5), -30 kPa/-30 kPa (S6), and -30 kPa/-45 kPa (S7). In each treatment, we measured growth, fruit quality, water consumption and water use efficiency of the tomato. 【Result】 Stem diameter increased with SMP threshold at both flowering and fruit-setting stage and fruiting stage, whereas the plant height was only responsive to SMP at flowing and fruit-setting stage. The relative chlorophyll content in leaf (SPAD) did not show significant difference between treatments at flowering and fruit-setting stage but inversely increased with the SMP threshold at fruit setting stage. Decreasing the SMP threshold at flowering and fruit-setting stage could reduce the percentage of defective fruits and increase soluble solids content. Yield increased inversely with SMP threshold at fruit setting stage, peaking when SMP was -45 kPa. Lowering the SMP threshold increased irrigation amount and hence water consumption, thereby decreasing water use efficiency.【Conclusion】Our experimental results suggest that setting the SMP at -30 kPa at the flowering and fruit-setting stage and -45 kPa at the fruiting period appears to be optimal to best balance yield, fruit quality, irrigation water use efficiency and water use efficiency for winter-spring tomato grown in solar greenhouse in North China. |
| Key words: Solar greenhouse; winter and spring growing tomato; drip irrigation; high yield and good quality; water use efficiency |
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