长江下游防虫网覆盖塑料大棚内小白菜蒸腾模拟

Transpiration of Brassica chinensis L.in a plastic greenhouse covered with insect-proof nets in lower reaches of Yangtze River:A simulation study

根据Penmam-Monteith蒸腾模型,建立了一个以单栋塑料大棚内外气象条件为驱动变量,以单栋塑料大棚结构、防虫网覆盖材料、大棚内小白菜特征宽度和叶面积指数为参数的小白菜蒸腾模型,并利用单栋塑料大棚内试验数据的独立样本对模型进行了检验.结果表明:长江下游地区覆盖20目、25目、28目防虫网单栋塑料大棚的流量系数分别为0.771、0.758和0.736,综合风压系数分别为0.33、0.37和0.39,模型对该地区夏季晴天、多云、阴天蒸腾速率预测值与观测值的决定系数(R2)分别为0.95、0.91和0.94,回归估计标准误差(RMSE)分别为0.018、0.014和0.015g·m-2.s-1,相对误差(RE)分别为14.27%、18.05%和15.80%.蒸腾模型能较好地预测长江下游地区防虫网覆盖单栋塑料大棚内小白菜的蒸腾速率.

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 （ Ca ） 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 （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.