Evaluation on the accuracy of sap flow measurement in longkong and mangosteen trees by comparing between PSU-NECTEC1 and Greenspan Sapflow sensors
2000
Sdoodee, S. | Ormsubsin, V. | Limsakul, C. (Prince of Songkla Univ., Songkhla (Thailand). Faculty of Natural Resources. Dept. of Plant Science)
Sapflow of longkong and mangosteen trees was measured by heat-pulse method, and the accuracy of the measurement was evaluated by comparing between the 2 equipments : PSU-NECTEC 1 and Greenspan Sapflow Sensors (a commercial equipment). On containerized 2-year-old longkong tree, sapflow was evaluated by using Greenspan Sapflow Sensors. It was found that there was only 4 percent differnce between sapflow and transpiration measured gravimetrically. Then, the sap flow of field-grown trees of longkong (8-year-old) and mangosteen (12-year-old) was measured by using PSU-NECTEC 1 and Greenspan Sapflow Sensors. The sapflow of longkong and mangosteen trees measured by PSU-NECTEC 1 was found to be less than that of Greenspan Sapflow Sensors. Only a 5 percent difference was found in longkong trees. In mangosteen trees the difference was higher than 10 percent; this might be due to the effect of gumming from stem that was drilled for implanting the probes.
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