LAUSR

Abstract Nitrogen partially regulates stomatal conductance and crop transpiration. We conducted greenhouse experiments into the effects of different nitrogen applications on the transpiration (T) of greenhouse pot-grown tomato plants with plastic film mulch in 2016–2017. We modeled the relationship between soil mineral nitrogen content and canopy resistance (rc) and incorporated our model into the Jarvis canopy resistance model to create the nitrogen modified Jarvis (N-Jarvis) model. We calculated transpiration under three nitrogen application levels, each with four irrigation programs using the Penman–Monteith (P–M) model with the Jarvis model and with the N-Jarvis model. Canopy resistance estimated by the Jarvis model differed greatly from observed canopy resistance, which was calculated by reformulating the P–M model and using the measured transpiration by sap flow system (TSF). The N-Jarvis model is more accurate than the Jarvis model in predicting rc. Similarly, the transpiration estimated by the P–M model with N-Jarvis model is more accurate than with the Jarvis model when compared to TSF, with higher values for the coefficient of determination and the modified efficiency coefficient, and lower values for the root mean square error and the Akaike information criterion. Including predictions from the N-Jarvis model improves the accuracy of the P–M model in estimating tomato transpiration under different nitrogen application levels.