THE GROWTH AND DISTRIBUTION OF FRUIT TREE ROOTS: SOME CONSEQUENCES FOR NUTRIENT UPTAKE

Nutrient uptake can occur either through the roots or the leaves.
Under natural conditions most nutrient uptake is via the roots but where foliar sprays are being used considerable amounts can enter via the leaves.
Allen (1970) found that up to 90 per cent of a magnesium spray could be absorbed by the leaves, while Ford (1968) showed that magnesium sprays could increase leaf concentrations by over 50 per cent.
Turner, Ferguson and Sharples (1977) using calcium and phosphate sprays increased fruit calcium from 3.0 to 4.8 mg/100 g fresh weight and phosphate from 7.4 to 12.9. A similar result was obtained by Fochessati, Perring and Johnson (1977). However, despite these instances, it is probable that even where foliar sprays are being applied that the uptake of nutrients from the soil will provide the main path for nutrient entry to the fruit tree.

Uptake by the roots will be influenced both by the root system and by its environment which, as well as directly affecting uptake, will indirectly influence it through effects on root growth.
The total volume of the root system, root density, the periodicity of both growth and activity in relation to tree demand and the distribution of the system through a soil volume where all horizons are not equally able to supply nutrients will all be important.
These parameters can vary between fruit types, cultivars and rootstocks and can be modified by the soil environment and orchard management.
The influence of some of these features and of other factors which affect the efficiency with which edaphic resources are used are discussed in this paper.

Symposium on Mineral Nutrition and Fruit Quality of Temperate Zone Fruit Trees

D. ATKINSON, SANDRA A. WILSON

https://doi.org/10.17660/ActaHortic.1980.92.17