ISHS Acta Horticulturae 732: VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems
CAN REFLECTIVE GROUND COVER COMPENSATE FOR LIGHT LOSSES UNDER HAIL NETS? |
| Author: | M.M. Blanke |
| Keywords: | Malus domestica Borkh., apple, anthocyanin, colour, firmness, fruit quality, light, sugar |
| DOI: | 10.17660/ActaHortic.2007.732.101 |
| Abstract:
An orchard of five-year-old cv. 'Jonagold Wilmuta' apple trees on M.9 rootstock was partially covered with either black or white hail nets. White, reflective ground cover was spread on the grass alleys in July or August 2003 to improve light utilisation in the orchard. Uncovered rows served as controls. Maturity and quality of the apple fruit at harvest, judged by fruit size, fruit firmness, starch breakdown and sugar content, was mostly unaffected by the use of either hail nets or the reflective ground cover. White reflective ground cover on the grass alleys between the tree rows enhanced fruit colouration, to a larger extent when spread earlier, i.e. July rather than August. The improved colour occurred primarily in shaded fruits or portions of the fruit, i.e. the lower, above ground section of the apple tree compared with its upper part and the inner and bottom side of the fruit relative to its outer side. The improved fruit colouration with ground covers under both hail nets, which reflected most of the UV-A and UV-B radiation, reduced temperature fluctuations and prolonged longevity of the ground cover, is hence attributed to increased intensity of visible (but not UV light) and not to temperature fluctuations. The present work showed that enhanced fruit colouration with retention of good fruit quality is possible under white and black hail nets if reflective ground cover is spread in the tree alleys six weeks before harvest. | |
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