In this paper,eddy covariance data from a winter wheat field on the Loess Tableland were used to
investigate the temporal variation of energy components,as well as the characteristics of energy partitioning and its
main controlling factors. Results showed that the total net radiation ( Rn) throughout the year was 2. 56 × 103 MJ·
m - 2·a - 1,and the energy balance closure degree was 0. 72. In the wintering and grain filling periods,the energy
components were dominated by upward sensible heat flux ( H) ,with a maximum value of 7. 09 MJ·m - 2·d - 1 occurring
in June. However,in other growing stages and the fallow period,the energy components were dominated by
upward latent heat flux ( LE) ,with a maximum value of 10. 71 MJ·m - 2·d - 1 occurring in May. The average of
Bowen ratio ( β) was 0. 57 in growing season and 0. 46 in the fallow period. The annual total amount of soil heat
flux ( G) was - 15. 26 MJ·m - 2·a - 1 . The daily total amount of soil heat flux ( G) reached a maximum value of
1. 85 MJ·m - 2·d - 1 in June,and it was negative from October to the next January,which showed the release of
heat from soil.
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