The influence of soil, hydrology, vegetation and climate on desertification in El-Bayadh region (Algeria)

Figures & data

Fig. 1 Geographical position of the study area ‘‘El Bayadh”.

Table 1. Land area for soils of different classes of vulnerability (Forest Service of the wilaya of El Bayadh, 2012)

Class	Area (ha)	%
Little or no vulnerability	31255.71	0.44
Moderately vulnerable	1144627.8	15.97
Vulnerable	3240757.76	45.20
Highly vulnerable	2594871.41	36.19
Desertified	157714.35	2.20
Total	7169227.03	100

Table 2. Mean Monthly rainfall of El Bayadh Metrology Station (1971–2010)

Months	Sept	Oct	Nov	Dec	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug
Ravg (mm)	23.1	21.9	21.6	18.9	20.1	18.5	30.3	22.6	22.08	20.03	10.5	16.2
Rmax (mm)	72.5	109.3	96	61.5	86	54	65.3	74.2	71.8	86.1	32.2	43
Rmin (mm)	0.2	0	0	2.9	0	0	2	0.4	0.9	0	0	0.1

R_avg, R_max and R_min: mean values.

Fig. 2 Year classification according to rainfall.

Table 3. Distribution of average monthly temperatures (Period: 1971–2010)

Months	Sept	Oct	Nov	Dec	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug
Tavg (°C)	21.8	16.5	10.3	5.9	5.2	6.5	10.8	11.5	18.2	22.3	27.4	26.9
Tmax (°C)	28.0	21.9	15.5	10.2	9.7	11.8	16.7	19.6	22.7	31.1	35.0	31.7
Tmin (°C)	15.7	11.1	5.0	1.5	0.7	1.1	2.9	7.4	11.8	17.5	21.1	20.2

Fig. 3 Ombro-thermal diagram for the study area ‘‘El Bayadh” (1971–2010).

Table 4. Wind speeds in the wilaya of El Bayadh (Period: 2006/2007)

Station	Sept	Oct	Nov	Dec	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug
Wind (m/s)	1.5	1.1	2.9	1.2	1.4	2.9	1.9	2.0	2.0	1.8	1.6	1.3	1.8 (average speed)
Frosts (days)	0	0.6	6.3	10.8	11.9	11.4	1.8	1.3	0	0	0	0	44.1 (total number)
Sirocco (days)	0.3	1.1	0	0	0	0	0	0.2	0.9	0.9	1.0	2.5	6.9 (total number)

Table 5. Nature of water in the wilaya (This data is obtained from the National Agency for Hydraulic Resources of the wilaya of El Bayadh, NAHR, 2012)

Nature	Available	Consumed	Rate%
Superficial waters (hm^3)	123	11.50	9.35
Groundwater (hm^3)	292.25	71.34	24.41
Total (hm^3)	415.25	82.84	19.95