关键词: 植物功能性状, 铁杆蒿, 适应策略

Abstract: Subsurface irrigation is a type of water saving technology. Current subsurface irrigation emitters have poor anti-clogging abilities and consume a lot of energy. Considering the disadvantages of old subsurface irrigation emitters, a new type of subsurface irrigation emitter-a vertical tube emitter-was proposed based on energyefficient by decreasing pressure head and improving anticlogging characteristics. In this study, the characteristics of cumulative infiltration of vertical tube emitter were examined. The hydraulic head and infiltration time were considered as factors affecting infiltration of the vertical tube emitter. The experimental scheme was established with different pressure levels (0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 m) and different tube diameters (4, 8, 12, and 16 mm). A Mariotte bottle was used to regulate the hydraulic head. The total infiltration time was 5 h for each trial, with the time intervals of 1, 2, 3, and 5 min during 0-50 min, respectively. Then, the time interval was 10 min for every record. During 100-180 min, the time interval was 20 min, and the last interval was 30 min from 180 to 300 min. The cumulative infiltration was observed and recorded with different pressure heads. The results showed that at the first infiltration stage, the value of cumulative infiltration was remarkably fluctuated. As the infiltration time went on, the fluctuation of the value decreased slightly and then tended to be stable. Pressure head had a significant influence on cumulative infiltration. Such effect was weakened with the infiltration time. There was a significantly positive correlation between tube diameter and cumulative infiltration, but this influence decreased with the increasing tube diameters. The correlation coefficients between observed values of cumulative infiltration and predicted values using pressure head and tube diameter as predictor variables were 0.997 and 0.998, respectively, indicating a good relationship between cumulative infiltration and influencing factors. Our results are important for further study on infiltration performance of vertical tube emitters in subsurface irrigation and the application of vertical tube emitters.

Key words: plant functional trait, Artemisia sacrorum, adaptation strategy.