持续性温强和土壤水分对玉米发育进程的影响及其模拟

作物的发育进程对产量形成有重要影响,在作物生长模型中也起着时间指针的重要作用。但目前逐日累积温度的发育模式无法解释作物播期不同而成熟期差距很小或基本相同的现象;目前对土壤湿度影响作物发育进程的规律也不十分清楚,多数作物生长模型也未予考虑。本研究以华北夏玉米为研究对象,首先对几种常用的作物发育模式进行稳定性比较,然后再分别探讨持续性温度强度和土壤湿度对夏玉米发育进程的影响规律,并构造相关模式。结果表明,积温(TSUM)、发育单位(CHU)和热量单位(THU)等发育模式中以THU的稳定性最高。夏玉米发育进程不仅由累积温度或热量单位决定,而且受持续性温度强度(某一发育阶段的平均温度)的明显影响。平均温度较高时,完成该发育进程需要累积更多的温度。据此建立的模式对夏玉米分期播种的发育进程模拟有明显改善。土壤水分对夏玉米发育进程有明显影响,水分增加将促使夏玉米营养生长阶段的发育加速,导致抽雄期提前。由此建立的模式对区域上夏玉米发育进程的模拟有一定改善。

Effects of Continuous Temperature and Soil Moisture on Development Process of Maize and Its Simulation

There is an important effect of crop development on yield formation. Development is the time pointer in the crop growth model. However, the current crop development model of cumulative temperature can not explain the phenomenon of different sowing date but same maturity. At the same time, how the soil moisture affects the crop development is not very clear and the majority of crop growth model does not consider this. In the paper, summer maize in north China was taken as the object to study the stability of several crop development models, effects of continuous temperature and soil moisture on development and its simulation method. The results showed that the stability of the heat units (THU) model was the highest in accumulated temperature (TSUM), developmental unit (CHU) and THU models. Summer maize development process was not only determined by the cumulative temperature or heat units, but also affected by the average temperature in a development phase. The completion of the development process needed more accumulated temperature while the average temperature was higher. A maize development model was established the base on this. This model obviously improved simulation of development process of summer maize, which sowed in different days. There was a significant effect of soil moisture on summer maize development. Increase of soil moisture would cause development acceleration of summer maize in vegetative growth stage. Thus, the tasseling stage would advance. The model based on this could better simulate summer maize development in regional scale.