土攘 및 植物의 水分포텐셜과 HR-33T 露點式 微電壓計에 의한 그의 測定 = Water Potential of soil and Plant and Use of HR-33T Dew Point Microvoltmeter for Its Measurement

다국어 초록 (Multilingual Abstract)

Development of water potential concept is reviewed firstly for the Korean scientists, and implications of water potential measurement in irrigated crop culture are discussed. Development and theoritical aspects of psychrometric methods of water potential measurement are outlined.
Also, the HR-33T Dew Point Microvoltmeter and sensors, C-52 sample chamber, L-51 leaf thermocouple and Pt-51 soil thermocouple, makes of the Wescor Inc, Logan, Utah, U.S.A and donations by Grant 69 of the International Foundation For Science, Stockholm, Sweden, were characterized ofr practical application in nutrio-irrigation culture of crops:
Cooling time requirement, moisture equilibrium time requirement, and linearity of μV output of the equipment over the range of water potential from -5 bars to -70 bars were as follows: cooling time was sufficient with 10 seconds for C-52, and L-51, and 15 seconds for Pt-51; moisture equilibrium time required was 5 minutes for C-52 and L-51, and about 1 to 2 hours for Pt-51 at the water potential of about -5 bars; shorter time was requried as the water potential of the sample decreases; linearity was Y(μV)=-0.617+0.597X (-bars) for C-52, Y=1.678+0.627X for L-51, and Y=1.378+0.624X for Pt-51; linearity was good enough and sensitivity of the thermocouples was much improved in the dew point method than the sensitivity of 0.47μV/bar in the psychrometric method, but it was still practically difficult to measure correctly the water potential higher than -0.5 bars.