VINE ROOT DISTRIBUTION UNDER IRRIGATION AND RAINFED CONDITIONS WITH SUPPLEMENTARY UNDERGROUND IRRIGATION

In grape vines grown both under rainfed condition in Jabal El-Akhdar of the Mediterranean climate or under irrigation in Fezzan Oasis of the dry desert climate, root distribution system both laterally and vertically is very important as it enables the vines to forage effectively for scarce water and nutrients.

Fibrous roots of rainfed vines in Jabal El-Akhdar, planted in heavy clay soil were found to grow down to 140 cm, but such growth was limited by compactness of the soil with resulting limitation in aeration.
In this area the top 20 cm soil layer dries out and at the same time is excessively heated with the result that root growth in this layer is drastically reduced.
Although laterally fibrous roots were found 3 m from the trunk, profiles dug 1 m from the vine trunks were richest in fibrous roots.
Most of the fibrous roots of irrigated vines in Fezzan Oasis grown in sandy loam soil not deep in comparison with the previous case were found between 0–50 cm depth.
There were 70% of roots in this layer and 30% of the roots were found from 50–90 cm depth.

In an attempt to reduce evaporation from the surface soil layer, young vines were supplied with water through hollow plastic tubes used as supporting stakes.
Water was applied on the surface, as is normally done, or was applied by drip.
Vines irrigated by drip system through the stake grew appreciably better and produced substantially more shoot and root growth per unit volume of water applied.
For the same amount of growth, surface irrigated vines required five times as much water as vines irrigated through the stakes.
Vines irrigated with drip on the soil surface gave imtermediate results.

X African Symposium on Horticultural Crops

H.M. Sawaf, S. Senfaz, S.O. Adam, A.K. Azaga, M.A. Ansari

https://doi.org/10.17660/ActaHortic.1985.158.23