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本文分析了华北平原冬小麦生态系统辐射收支、热量平衡以及蒸散在冠层蒸腾和土壤蒸发之间的分配特征。结果发现，在冬小麦生长过程中，系统截获的太阳短波辐射随小麦的生长而变，它占太阳总辐射的比例，初期为０．８左右，尔后随叶面积的增加而逐渐下降，在孕穗期最小，约为０．７５，之后，随叶片枯黄、麦穗的成长又上升，最后可达０．８６。净辐射占太阳总辐射的比例，可分成如下３个阶段：拔节期比值较低，约为０．４５；孕穗抽穗期约为０．５；灌浆期比值最大，约０．５７。随着叶面积指数（ＬＡＩ）的增加，土壤热通量与净辐射之比，由返青初期的０．１３迅速下降，直至较为稳定的０．０６。潜热通量消耗净辐射的大部分，且随ＬＡＩ的增加而增大。从返青到乳熟的５８天内（４月１日～５月２８日），麦田总蒸散量约为２５０ｍｍ，其中土壤蒸发量约为５０ｍｍ，冠层蒸腾约为２００ｍｍ，分别占总蒸散量的２０％和８０％。
In this paper, the radiation budget and heat balance of winter wheat ecosystem in North China Plain and the distribution of evapotranspiration between canopy transpiration and soil evaporation were analyzed. The results showed that during the growth of winter wheat, the solar shortwave radiation intercepted by the system changed with the growth of wheat, which accounted for the proportion of total solar radiation, the initial ratio was about 0.8, and then decreased gradually with the increase of leaf area. The smallest, about 0.75, then, with the leaves of yellow, the growth of wheat rose again, finally up to 0.86. The ratio of net radiation to total solar radiation can be divided into the following three stages: the lower jointing stage is about 0.45; the booting stage is about 0.5; and the highest filling stage is about 0.57. With the increase of leaf area index (LAI), the ratio of soil heat flux to net radiation decreased rapidly from 0.13 in the early stage of rejuvenation to a stable 0.06. The latent heat flux consumes most of the net radiation and increases with increasing LAI. Within 58 days (April 1 to May 28), the total evapotranspiration in the field was about 250 mm, of which the soil evaporation was about 50 mm and the canopy transpiration was about 200 mm, accounting for 20% of the total evapotranspiration % And 80%.