ISHS Acta Horticulturae 276: II International Symposium on Computer Modelling in Fruit Research and Orchard Management
A COMPUTER MODEL OF SHADE CAST BY SHELTERBELTS AROUND KIWI FRUIT ORCHARDS |
| Authors: | J.W. Palmer, W.P. Snelgar, P.J. Manson |
| Abstract:
Kiwi fruit orchards in New Zealand are bounded on all four sides by shelterbelts to protect the fruit from rubbing and to prevent the new shoots being blown out. Although the shelterbelts undoubtedly protect the vines from wind damage they also reduce the light reaching the vines. Shading trials in New Zealand have already shown that the yield of kiwi fruit is reduced by shading. The shelterbelts may be up to a height of 20 m and each orchard typically is 150 m long by 50 m wide, although there is considerable variation in all these dimensions. A computer model of the shade cast by the shelterbelts would obviously allow rapid assessment of the effects of shelterbelt height, porosity, orientation and block size on the light available for the kiwi fruit. A computer model originally developed to calculate light interception by hedgerow apple orchards in England was taken to New Zealand in the beginning of 1989 and modified to calculate the irradiance over the orchard above the kiwi fruit vines. The model was validated by measuring irradiance above the canopy in commercial kiwi fruit orchards in the Te Puke area of New Zealand at the same time. These orchards had a range of shelterbelt species - poplar, willow and Casuarina - and also an artificial material. Calculated irradiance from the model compared well with measured values under both sunny and diffuse conditions. This project illustrates the great versatility of computer models, that once developed they can relatively easily be modified for different crop species and locations. | |
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