S.G. Middleton, J.E. Jackson
The use of solid tree models placed on a flat-bed solarimeter in the field is a simple, rapid method to measure Fmax (light interception by non-transmitting canopies) of even the most complex orchard designs. Estimates of light interception by real orchards of the same layout as the models can be calculated using Fmax and values for leaf area and the light extinction coefficient.

This approach was tested on four orchard systems at East Malling Research Station, Kent. Scale models based on field measurements of tree size and spread were designed to represent Cox's Orange Pippin trees grown as a three-row North Holland system on M.9 and M.27 rootstocks (2632 trees per ha), a zig-zag double-row system on M.9 (2000 trees per ha) and a single-row system on MM.106 (667 trees per ha). Light interception by these systems was also measured using selenium cells, to test the validity of estimates made with the flat-bed solarimeter.

The 'solid model' concept predicted the light interception of the four systems to within 5% of selenium cell measurements. By using models of different shapes and dimensions, and altering model positions to represent different planting designs, the flat-bed solarimeter can also be used to evaluate the potential light interception of orchard designs prior to planting.

Middleton, S.G. and Jackson, J.E. (1989). 'SOLID MODEL' ESTIMATION OF LIGHT INTERCEPTION BY APPLE ORCHARD SYSTEMS. Acta Hortic. 240, 83-86
DOI: 10.17660/ActaHortic.1989.240.12

Acta Horticulturae