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| DOI：10.13522/j.cnki.ggps.20180360 |
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| Using Soil Matric Potential Underneath the Drip Emitter to Regulate Soil Moisture Distribution and Improve Greenhouse Tomato Production |
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WAN Shuqin, YAN Zhenkun, KANG Yuehu, YUAN Baozhong, JIAO Yanping, SONG Jia
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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】 Soil moisture controls crop growth. In this paper, we investigated how to regulate soil moisture distribution by drip irrigation using the matric potential measured underneath the drip emitter in attempts to improve greenhouse tomato production.【Method】The experiment was for winter-spring season tomato grown in a solar greenhouse. The treatments were to maintain soil matric potential 20cm underneath the drip emitter at seven levels: -15 kPa (S1), between -15 kPa and -30 kPa (S2), between -15 kPa and -45 kPa (S3), between -25 kPa and -25 kPa (S4), between -30 kPa and -15 kPa (S5), between -30 kPa and -30 kPa (S6), and between -30 kPa and -45 kPa (S7), during flowering-fruit setting and fruiting stage. In each treatment, we measured spatiotemporal soil moisture distribution, yield and visual defects of the fruits, as well as use efficiency of the irrigation water. 【Result】The matric potentials had a significant impact on moisture distribution in 0~100 cm soil. ① When the matric potential was controlled at -30 kPa or above during flowering -fruit setting stage, most water in 0~60 cm soil was taken up by roots while the water in soil below 70 cm remained almost unchanged; the average volumetric water content in 0~60 cm soil was 28.6%, approximately 84% of the field water capacity. In 60~100 cm, the average soil moisture was 36.2%, about 90% of the field water capacity. ②When soil matric potential was controlled between -15 kPa and -25 kPa during the fruiting stage, the soil water content was approximately 77% to 91% of the field water capacity, and most water in 0~60 cm was used by the crop, compared to water below 70 cm. ③When the soil matric potential was between -30 kPa and -45 kPa, crop could take water from 80~100 cm soil and the soil water content reduced to 66% of the field water capacity. There was a significant difference in tomato yield, fruit defects, and use efficiency of irrigation water between the treatments. The yield was comparatively high in S3 and S7, and low in S5 treatment; visual fruit defect rate was high in S1, S3 and S4, and low in S6 and S7; the irrigation water use was least efficient in S1 and most efficient in S7. 【Conclusion】Controlling soil matric potential at 20 cm below the emitter at -30 kPa during the flowering-fruit setting stage, -45 kPa during fruiting stage, improved tomato yield and irrigation water use efficiency; it also reduced visual fruit defects. |
| Key words: solar greenhouse; moisture; soil matric potential; irrigation; tomato; yield |
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