Plant transpiration and net entropy exchange on the Earth's surface in a Czech watershed

Abstract

The influence of plant transpiration on the entropy exchange was quantified as associated with the degradation of solar energy on the Earth's surface covered by plants. Two surfaces were studied: (1) productive surface - plant transpiration taken as equal to the potential one, (2) non-productive surface - plant transpiration taken as equal to zero. The entropy exchanges associated with the absorption of solar radiation and with the conversion of absorbed solar radiation into the sensible heat and latent heat were taken into account. These processes were examined in the experimental watershed Liz (828-1074 m a.s.l.) located in the Bohemian Forest (Czech Republic). We found that in the growing season 1992 the net entropy exchange in humid hydrologic period (the Earth's surface is productive) was considerably higher than in the arid one (the Earth's surface was productive in 39% of days, and non-productive in 61% of days). Considering that the biotic effect on the Earth's functioning can be measured with the help of the net entropy exchange, we can assume that the theory that biotic activities - represented by plant transpiration here - are the cause of the self-organizing processes in Earth's environment is proved in the watershed scale. © 2007 Institute of Botany, Slovak Academy of Sciences.