Energy, production and biomass in ecosystems
1982
Thalen, D.C.P. (Rijksinstituut voor Natuurbeheer, Leersum (Netherlands))
A brief introduction is presented on the energy flow, primary production and biomass accumulation in ecosystems, based on information from literature sources. First the energy flow in the natural ecosystems is outlined emphasizing the losses at the various levels. This is followed by a comparison of biomass and productivity in the world's major vegetation units and agricultural areas with remarks on the limiting factors and the input of fossil energy in agricultural systems. A comparison of energy conversion efficiencies in woodlands and agricultural crops shows the relatively high values for the first. The possible causes are briefly discussed. Data from Van der Drift c.s. on energy conversion and fixation in an oak woodland in the Netherlands are summarized. Finally the calorific values of various plant materials are given.
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