Leaf area index measurement and its agronomical incidence in apple trees | Mesure de l'indice de surface foliaire et incidence agronomique sur le pommier
2003
Monney, Ph. | Henriot, C. (Station federale de recherches en production vegetale de Changins (RAC), Conthey (Switzerland). Centre d'arboriculture et d'horticulture des Fougeres.)
Although many factors will influence yield, Leaf Area Index (LAI) of different orchards can be correlated with their fruit production as long as the light energy received is comparable. Related to average light exposition or not, LAI is a key factor for evaluating the agronomical potential of an orchard. In this paper, a LAI measurement method used for two different research scopes is presented. With orchard systems based on different shapes, canopy illumination and fruit quality may be similar if pruning is used to remove shaded branches. Such systems will reach the critical LAI level for fruit quality preservation within a few years. Combined with fruit-leave relationship, LAI allows to estimate optimal yield for each system. A yield increase of 10 to 30% with V-shaped systems is possible when compared to traditional axis orchard design. Apple leaf area develops quickly after full bloom stage. When removal of complet fruiting spurs (artificial extinction) is practised, part of the light interception potential is virtually eliminated. The tree is able to compensate this loss by an increased average vigor of spurs and extinction shoots. The frequency of more developed elements such as strong spurs and shoots increases to the costs of undersized spurs.
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