Hydraulic weighing lysimeters are widely used for determining rates of evapotranspiration of agricultural crops. This paper contains the results of a laboratory study using a prototype size lysimeter to study accuracy and sources of error that might be caused by variable pillow contact area, temperature changes in various components of the indicating mechanism, and rate of lysimeter loading. The effect of degree of inflation of the hydraulic pillows on bearing plate contact area is examined in detail and found to have a significant effect on lysimeter calibration. Hysteresis in the indicating mechanism was not significant. The effects of rapid changes in lysimeter tank mass relative to gradual mass changes are evaluated and found not to significantly affect lysimeter response.
|Transactions of the American Society of Agricultural Engineers
|Published - Jan 1989
ASJC Scopus subject areas
- Agricultural and Biological Sciences (miscellaneous)