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The tree-crop interface: representation by coupling of forest and crop process-models.

Lawson, G.J.; Crout, N.M.J.; Levy, P.E.; Mobbs, D.C.; Wallace, J.S.; Cannell, M.G.R.; Bradley, R.G.. 1995 The tree-crop interface: representation by coupling of forest and crop process-models. In: Korpilahti, E.; Salonen, T.; Oja, S., (eds.) Caring for the forest: research in a changing world. Vienna, IUFRO, 107.

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Abstract/Summary

Abstract in full: Three process-based approaches to agroforestry modelling are described. These are (a) coupling a continuous-canopy forest model (Hybrid) and tropical crop model (PARCH); (b) coupling an individual-tree model (MAESTRO) with a crop model (PARCH); and (c) incorporating a combined model of evaporation and radiation interception by neighbouring species (ERIN). The coupled Hybrid/PARCH was parameterised for maize and eucalyptus, and run in five contrasting weather-types, As expected, shade is the most important factor limiting yield in wet sites; water in dry sites. Year-to-year variability in crop yield is increased by light and water competition, MAESTRO/PARCH was run with similar assumptions, and gave comparable yield predictions, except at the driest site where it allows small areas distant from the tree sufficient water to produce a modest yield. Hybrid/PARCH predicted total crop failure in the same climate. Yields on drier sites were higher in the shade, but water competition was severe close to the tree. ERIN is simpler than the above models, but is unique in including the transfer of heat and water vapour between the two canopies. Transpiration from a moist understorey can humidify air in the overstorey, and reduce its transpiration; whilst a dry understorey will give off sensible heat, which increases the vapour pressure deficit in the overstorey and causes its transpiration to increase. Changes in overstorey transpiration due to fluxes from the understorey may approach 15-20%.

Item Type: Publication - Book Section
Digital Object Identifier (DOI): 10.1007/BF00708921
Programmes: CEH Programmes pre-2009 publications > Other
CEH Sections: _ Pre-2000 sections
Additional Keywords: Agroforestry
NORA Subject Terms: Agriculture and Soil Science
Date made live: 26 Jun 2009 15:24
URI: http://nora.nerc.ac.uk/id/eprint/7596

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