Evaluating the energy flow in a model farm watershed
1991
Bebrova, J. | Gergel, J. (Vyzkumny Ustav Melioraci a Ochrany Pudy, Prague-Zbraslav (CSFR))
In the drainage area (7.11 km2) of the Budsky Creek in the Sumava foothill region, the main items of the energy balance were studied in 1987-1988 to get data for an investigation of the effects of complete land improvement systems. A considerable difference was demonstrated to exist between the two years in which the investigation was carried out. The values of input solar radiation energy, derived from the PhAR, ranged between 15 and 16 TJ per ha. The remaining parameters of energy input and output under study had significantly lower values: fertilizers 12 - 14 GJ 30 - 32 GJ, fuels 3.0 - 3.4 GJ manual work energy, depending on the species of the crop cultivated, ranged between the orders of mega and giga, and the power of the mechanisms used within the area ranged between 2.8 and 24 GJ. The yield, depending on the crop represented power values of 93 - 130 GJ, and the amount of nutrients carried away with water represented a power loss of 2.3 - 3.1 GJ per ha. The available PhAR energy for selected crops and their total power demand are determined in detail in the paper. The ratio of additional energy inputs and the energy outputs is also shown.
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