Vol. 35 – 2009 - Ecologia Mediterranea - Université d'Avignon et des ...

Materials and methods
Choice of the study area
The Ouargla commune which is located at the
center of the Ouargla basin was chosen
because this site takes into account importance
of its date palm crop heritage (DPAT
2001) and, abandonment and deterioration of
several of its palm plantations caused by the
effects of groundwater rise on growth of the
date palm.
Date palm areas are chosen from five areas
which all are agrarian ecosystems: namely
Bamendil, Mekhadma, Ksar, Said Otba and
Beni Thour. Our investigation dealt with 167
palm plantations between 15 and 45 years old
(Figure 1). The whole of these areas forms
97% of the total surface, occupied by date
palm crops in Ouargla district (DSAO 2001).
Hydro-edaphic study
Our methodological approach consisted of
measuring the parameters of the degradation:
groundwater levels and salinity, crusts levels,
irrigation water and soils salinity.
Figure 1 – The date palm areas in the Ouargla basin.
ecologia mediterranea – Vol. 35 – 2009
Effects of hydro-edaphic environment on the rooting of date palm (Phoenix dactylifera L.) Deglet Noor
in the Ouargla Basin (south-east algeria)
Study was carried out during winter period
(2002) when groundwater level reaches its
maximum. We measured water table depth
(W.t.d.) compared to soil surface using an
electric probe, and we collected water to measure
electric conductivity of water table
(E.C. w.t. ) at 25 o C with a conductivimeter.
Groundwaters were classified in 4 water table
groups, ranging between 0-40 cm, 40-80 cm,
80-120 cm and higher than 120 cm of depth.
The gypseous crusts depths (G.c.d.) were
determined by a gradual survey. Nature of the
crusts is given following maps and soils toposequencies
of the Ouargla basin (Hamdi Aïssa
2001), and confirmed by fast tests at the laboratory.
First, the test of effervescence with
HCl enabled us to determine presence of
limestone, and secondly, the test of precipitation
of sulphates by BaCl 2 enabled us to determine
presence of gypsum (Aubert 1978). We
also measured the electric conductivity of irrigation
water (E.C. i.w. ), and soils salinity at 0-
40 cm depth level. The samplings of soil were
carried out with an auger and the measurement
of electric conductivity of soil-water
extract 1:5 (E.C. e1:5 ), at 25 o C.
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