河套地区玉米叶面积指数的动态模拟

Dynamic Simulation of Maize Leaf Area Index in Hetao Region

以河套灌区玉米为研究对象,设7个玉米播期,从4月1日开始每10d一个播期,通过观测玉米生育期气象条件和不同播期玉米叶面积指数,建立玉米叶面积指数LAI动态模型。首先建立以生理日数为自变量的普适模型,利用该模型计算的第1-4播期玉米叶面积指数最大值出现在吐丝期后23-26d,第5-7播期的LAI最大值则出现在吐丝期后13-19d,模型对准确描述叶面积指数生长规律有一定局限性。然后,以积温为自变量对模型进行修订,结果显示该模型计算的第1-4播期的LAI最大值点的活动积温为1901.2-1996.7℃·d,第5-7播期的则为1579.7-1825.6℃·d,但该模型并未剔除低于10℃的无效积温,仍有一定局限性。最后,采用修正的Logistic方程构建玉米相对叶面积指数动态普适模型,方程均通过0.01水平的显著性检验,标准化后数据点的离散程度明显下降,出苗后有效积温达1004.4℃·d时河套地区玉米叶面积指数达最大值。研究结果可为准确模拟玉米叶片生长及光合产物分配提供依据。

The maize experiment was conducted with 7 different sowing stages from April 1, with interval 10 days in Hetao region. A dynamic model of maize leaf area index （LAI） was established by observing meteorological conditions in maize growth duration and investigating maize leaf area index in different sowing date. Firstly, the pervasive model was established taking phyological date as independent variable, which had certain limitation to express the LAI growth of maize. The model calculated that the maximum LAI was found in 23 -26 days after silking stage for 1^st -4^th sowing stage, and 13 - 19 days after silking stage for 5^th - 7^th sowing stage. Secondly, the model was modified by taking accumulation temperature as independent variable, which also had certain limitation to express the LAI growth of maize as the model did not removed accumulation temperature ≤10℃. The model calculated that the range of active accumulation temperature for maximum LAI was 1901.2 -1996.7℃ · d for 1^st -4^th sowing stage, and 1579.7 - 1825. 6℃· d for 5^th -7^th sowing stage. Finally, the pervasive dynamic model on maize relative LAI was established with modified logistic equation, which undergone the significant test （P≤0. 01 ）. The maximum LAI value was found at active accumulated temperature 1004. 4℃ · d after seeding. The results could provide reference for simulation accurate to maize leaf growth and distribution of photosynthate.