Guan'gai paishui xuebao (May 2021)

Study of Dew in Cotton Field under Drip Irrigation

  • MA Ruisha,
  • QIAO Changlu,
  • GE Ruichen

DOI
https://doi.org/10.13522/j.cnki.ggps.2020588
Journal volume & issue
Vol. 40, no. 5
pp. 93 – 99

Abstract

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【Background】 Dew is an important part of water resources besides precipitation in arid and semi-arid regions. This ‘non-precipitation’ water is of great significance to the ecosystem and water balance. 【Objective】 The effect mechanism of dew in cotton field was analyzed to provided a scientific basis for the sustainable development of drip irrigation technology under mulch film. 【Method】 A large-scale weighing lysimeter was used to monitor the dew of cotton field. A typical day was selected from different growth stages to analyze the condensation process. Two drip irrigation methods, drip irrigation under mulch and drip irrigation without mulch, were compared to analyze the effect of drip irrigation under mulch on the dew amount. 【Result】 ①The condensation process started at 00:00 and ended at 08:00, which lasted for 8 hours. Condensation and evapotranspiration appeared alternately between day and night. ②The condensation process could be divided into three stages: slow condensation, rapid condensation and converting to evapotranspiration. ③In different growth stages, the condensation rate reached the maximum at 01:00—03:00, and then showed a trend of gradual decline. ④There was a positive linear correlation between the amount of dew and the relative humidity (RH) and dew point temperature (Td), and a negative linear correlation between the amount of dew and the surface temperature (Ts), wind speed (Ws) and ambient temperature (Ta) under the two drip irrigation conditions. The condensation process of cotton field dew mainly occurs at night, the amount of dew and evapotranspiration at different growth stages were as follows: blooming and boll stage> buding stage > boll opening stage > seedling stage. The amount of dew under no mulch condition is 25.86% higher than that under mulch. 【Conclusion】 Film mulching does not affect the dynamic change of water vapor condensation. However, no film mulching method is more conducive to the generation of dew, film mulching method is not conducive to the dew into the soil.

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