Abstract: 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 (Cd) 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 (Cw) was 033, 037, and 039, respectively. The determination coefficient (R2) 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·m-2·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.

Key words: Brassica chinensis L., plastic greenhouse, insect-proof net, transpiration, lower reaches of Yangtze River, plastic film mulching, straw mulching, soil moisture, dryland, winter wheat.