准确模拟叶面积指数是作物生长模拟模型预测作物生长和产量的关键.本文通过系统分析扬州和武汉地区不同大麦品种高产群体叶面积指数变化动态，建立了大麦群体的叶面积指数模拟模型.大麦叶面积指数是品种叶面积指数扩展的遗传参数和气温日较差、日照时数、辐射量等气候因子及水肥丰缺因子的函数.孕穗抽穗期最大叶面积指数与该期最适叶面积指数是不同的概念，二者之间存在着极显著差异.利用扬州、南京和昆明地区不同品种的播期试验及氮肥试验资料对模型进行了检验，结果表明，模型对大麦叶面积指数的模拟效果较好，模拟值与观测值吻合度高，根均方差RMSE介于0.742～2.865，平均值为1.348.对模拟值与观测值进行y=x的线性回归分析，相关系数R2介于0.511～0.954，均呈极显著正相关.
To simulate leaf area index (LAI) accurately is the key for the prediction of crop growth and yield in a crop growth model. Based on the analysis of the dynamic changes in the LAI of high yielding barley cultivars in Wuhan and Yangzhou, a simulation model of barley LAI was established, in which, the LAI was the function of expansion coefficient of LAI for cultivar genetic property, climatic factors such as daily air temperature difference, sunshine hours, and accumulation of photosynthetic available radiation after sowing (∑PAR), and limitation indices of water and nutrients. It was indicated that the maximum LAI and optimal LAI at the stages of booting and heading were not the same conception, but differed significantly. The model was tested by the field experiments with different barley cultivars under different sowing dates and nitrogen application rates in Yangzhou, Nanjing, and Kunming. The results showed that this model gave thegood predictions of LAI at different development stages, with the RMSE values ranged in 0.742 and 2.865, and averaged 1.348. The simulated and observed LAI values were significantly positively correlated, and the correlation coefficient from y=x regression analysis was between 0.511 and 0.954.