水稻光合-蒸散耦合模型与不同株型的水分利用效率

Rice Photosynthesis-Evapotranspiration Model and the Effect of Crop Type on Water Use Efficiency

在前人研究的基础上 ,建立了水稻光合 蒸散耦合模型 (PE模型 ) ,其主要特点是 :①改进了Monteith的蒸散模型 ,使之由“大叶”模型成为群体分层结构模型 ;②通过提出阻风系数概念 ,建立了一系列可模拟群体中各叶层风速、边界层厚度、边界层阻抗、湍流交换系数、群体动力阻抗等要素的子模型 ;③应用群体光合作用模型和改进的Ball公式 ,将以上各要素连接起来 ,实现了光合模型与蒸散模型的耦合。利用PE模型 ,分别模拟了水稻前中期与后期不同株型的群体光合量、蒸散量以及水分利用效率。结果表明 :不论在前中期或后期 ,都以“上挺下披”株型的水分利用效率为最高 ,因为这种株型不仅光合量最高 ,而且蒸散量较小。

A coupling model of rice photosynthesis evapotranspiration model(PE Model)was established on the basis of former studies.The main characters of the model are:①improving Monteiths equation by converting it from a 'large leaf' model into a multiple layer model;②establishing a series of submodels which are able to simulate the wind speed within the canopy,boundary layer thickness,boundary resistance,turbulent exchange coefficient and canopy dynamic resistance,etc.by introducing a new concept of wind resistant coefficient(WRC);③realizing the connection of rice photosynthesis with evapotranspiration(PE) by using the improved Balls equation and the rice photosynthesis model,involving the elements mentioned above.Using the PE Model,the canopy photosynthesis,evapotranspiration and water use efficiency(WUE) for different rice plant types were simulated.The results indicate that both at the early and late stages in rice growing period,the plant type of UE/LF(upper erect lower flat)has the highest WUE,due to a higher photosynthetic product and lower evapotranspiration.There exists a good relationship between the simulated values and the observations for yield,evapotranspiration and the crop coefficient for rice.