Abstract Although shelterbelts in kiwifruit (Actinidia sp.) orchards reduce the negative effects of wind, they reduce the direct sunlight received. The shadow lengths of shelters 10 m taller than the kiwifruit canopy in theoretical blocks (150 x 50 m) orientated in 10° intervals from 0° (north-south) to 90° (east-west) were calculated at every minute for New Zealand locations. These shadow lengths allowed calculation of sunlight duration at each of 6439 transect points across the 0.6 ha canopy blocks. From these the average sunshine minutes of blocks were compared on a number of dates for various shelter orientations and locations. Contour maps displayed the variation in sunshine duration received across blocks at Tauranga in December, March, and June. There appears to be no obvious disadvantage of shelter orientations of 10°-40° compared with 0° (north-south). Lack of sunlight uniformity in blocks is discussed in relation to potential for fruit segregation at harvest.
Keywords kiwifruit; Actinidia; shelter; orientation; sun; shadow; wind; model
H03044; Online publication date 11 November 2004 Received 30 April 2003;
accepted 30 August 2004
New Zealand Journal of Crop and Horticultural Science, 2004, Vol. 32:
407-417
0014-0671/04/3204-0407 $7.00 © The Royal Society of New Zealand
2004
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