Evapotranspiration and Porometry

• Direct readout of stomatal conductance or resistance
• Simple absolute calibration in the field
• Minimises leaf stress during measurement

The AP4 is a highly practical field instrument for field work, based on the cycling diffusion principle, which makes it possible to have a lightweight sensor head (130g) and to run quick calibration checks in the field

• Calculates reference evapotranspiration (ET0)
• FAO Penman-Monteith and other calculations
• Daily and hourly (or timestep) ET0 results

Reference evapotranspiration (ET0) can be calculated by the ET2 Software from meteorological data.