夏玉米茎流和茎直径变化规律及其关系分析

通过对夏玉米生育期的茎直径微变化和茎流变化过程的监测,分析了茎直径微变化、茎流随土壤含水率和气象因子的变化规律,并对茎流与茎直径微变化之间的关系进行了分析。结果表明,茎直径微变化的日变化过程呈现明显的昼夜变化规律,白天收缩,夜间复原;茎直径日最大收缩量随含水量的升高而降低,可将其作为诊断作物水分状况的一个指标。茎流同样呈现明显的昼夜变化规律,白天茎流逐渐增大,在13:30左右达到最大值,然后减小。茎直径微变化、茎流的变化均受到太阳辐射、饱和水汽压差、空气温度、风速的影响。茎直径微变化与主要气象因子均呈负相关,茎流与其均为正相关关系。茎直径微变化与茎流之间呈负相关关系,且相关性很好。

The Movements and Relationships between the Stem Diameter Variation and Sap Flow for Summer Maize

It was presented that the change rules of stem diameter variation and sap flow for summer maize,as well as the relationship between them and the correlation with the meteorology factors,based on the field monitoring in Daxing experiment station.The results showed that the diurnal variations of stem diameter were very clear with shrinking in daytime and recovering in night.The Maximum Daily Shrinkage,MDS,could be a good diagnostic index of crop water message due to the significant change with the soil water content.The same movement was showed on the sap flow in day and night,and the maximum value of it appeared at 13:30.The change of stem diameter variation and sap flow were impacted by the field meteorology factors,such as solar radiation,vapor pressure deficit,air temperature,wind speed.However,the relationships were negative between the stem diameter variations and the main meteorology factors,and the sap flow was opposite.The regression analysis showed that the good negatively correlation between the stem diameter variation and the sap flow for summer maize.