Commercial soil thermocouple psychrometers of both the single junction and double junction types were tested to evaluate the magnitude and significance of Joule and resistance heating on water potential determinations near saturation. For water potential determinations about about minus 4 bars a cooling current of 8 mA produced significant heating and yielded unreliable results for both probe types. A cooling current of 3 to 4 mA applied for 15 s provided reliable determinations of water potential up to about minus 0. 5 bars when psychrometer output was read 6 s after cessation of cooling.
|Original language||English (US)|
|Number of pages||7|
|Journal||Transactions of the American Society of Agricultural Engineers|
|State||Published - Jan 1 1980|
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)