RESUMO
With the climate data inside and outside a plastic greenhouse as driving variables, and the greenhouse structure, insect-proof net material, and characteristic breadth and leaf area index of Brassica chinensis L. as parameters; a canopy transpiration model for greenhouse B. chinensis was established, based on Penmam-Monteith transpiration model. This established model was validated by the experimental data of independent samples in a single greenhouse. The results showed that in lower reaches of Yangtze River, the vent discharge coefficient (Cd) of greenhouse covered with 20-, 25-, and 28- mesh insect-proof nets was 0.771, 0.758 and 0.736, and the wind pressure coefficient (Cw) was 0.33, 0.37, and 0.39, respectively. The determination coefficient (R2) between the predicted and measured canopy transpiration rate for the sunny, cloudy, and overcast days in summer was 0.95, 0.91, and 0.94, root mean squared error (RMSE) was 0.018, 0.014, and 0.015 g x m(-2) x s(-1), and relative prediction error (RE) was 14.27%, 18.05%, and 15.80%, respectively, suggesting that this model could better predict the transpiration rate of B. chinensis in the plastic greenhouse covered with insect-proof nets in lower reaches of Yangtze River.