The article discusses different ways to calculate evapotranspiration using lysimeter measurements. Lysimeters are tools that help measure water balance parameters like precipitation and evapotranspiration. One method involves subtracting leachate and storage change from precipitation, but this can be affected by errors from precipitation gauges. Another method averages lysimeter mass measurements over time to reduce random noise. Threshold values can also be used to separate real mass changes from noise. Overall, lysimeters are useful for understanding water processes and can help calibrate environmental models for managing water resources.