冬小麦农田中净辐射的研究

本文对陕西泾阳地区冬小麦田净辐射进行了分段和分层模拟，取得了较好的拟合效果，相对误差在１０％以内。确定了麦田相对叶面积函数最大值的出现高度为４．５／７Ｈ，介于高粱（４／７Ｈ）和谷子（５／７Ｈ）之间。计算了不同发育期、不同层次至冠层顶部累积叶片的消光系数，结果表明，消光系数因发育期和叶片层次而异，拔节期，由旗叶向下，消光系数增大，乳熟期旗叶的消光系数最大，比拔节期大一倍，倒二叶以上两个层次叶片消光系数较小。就平均而言，冬小麦消光系数拔节期为０．５１，乳熟期为０．５６。本项成果为进一步开展麦田小气候研究提供了有意义的数据和方法。

A STUDY OF NET RADIATION IN WINTER WHEAT FIELD

In this paper,net radiation in winter wheat field was modeled layer by layer and segment by segment respectively in Jingyang area of Shanxi Province.And good results were achieved with relative errors below 10%.The height at which the maximum leaf area thickness function presents was defined as 4 5/7 of the plant height.Extinction coefficient,calculated for developmental phases and canopy layers,was somewhat different.For example,in elongation stage,it rose from flag leaf downward.In the milky ripening stage,it was the biggest as to the flag leaf,and was twice as big as in the elongation stage.On average,the extinction coefficient of winter wheat reached 0 51 in elongation stage and 0 56 in milky ripening stage.This study may provide valuable data and a method for further research into microclimate in wheat fields.