Die Bodenkultur - Journal for Land Management, Food and Environment
The effects of the environmental factors on the evapotranspiration in different growth phases of soybean
In this paper the actual evapotranspiration of soybean was calculated in three growth phases - from emergence to 2nd leaf, from flowering to first pod and from pod maturity to harvest- by the Bowen ratio energy balance method in Gross-Enzersdorf near Vienna/Austria during the extremely warm season in 1992. The estimated energy balance of soybean was used to investigate the relationships between the measured evapotranspiration, in addition to the measured global radiation, air temperature, wind speed, vapour pressure deficit, soil water content in different depths, and leaf area index under different growth phases. It was found that the air temperature is an important factor for the first growth phase. The global radiation and the wind speed play essential roles for evapotranspiration during the first and second growth phases of soybean. In addition, specifically the leaf area index for all growth phases and soil water content at 15 cm depth far second and third growth phases affected the evapotranspiration of soybean.
Key words: Evapotranspiration, soybean, bowen ratio, agrometeorology.