Geostatistical Modeling of the Spatial Distribution of Physico-Chemical Properties of Soil Cultivated with Cereals Under a Pivot Irrigation System in the Algerian Sahara: A Case Study in Biskra, Algeria

Assessing the sustainability of agricultural production systems in irrigated regions demands
meticulous examination of soil quality, particularly within cereal-cultivated areas under pivot
irrigation systems. This study investigates the intricate spatial dynamics of soil properties within
two distinct regions: Ourlal and El Outaya, both situated in Biskra, Algeria. Through systematic
sampling and analysis spanning four years of cereal cultivation, we rigorously assessed key
parameters including irrigation water quality, granulometry, pH, electrical conductivity (EC),
organic matter (OM), and equivalent calcium carbonate (total limestone).
In Ourlal, granulometry analysis revealed sandy loam soil dominance, with pH values ranging from
moderately alkaline in cultivated soils to slightly alkaline in the reference soil. Notable salinity
levels were observed in irrigation water, with EC values indicating high salinity levels in cultivated
soils and moderate salinity in reference soils. Total limestone measurements suggested a strongly
calcareous character across all sites with low organic matter content. Variogram modeling
elucidated Gaussian and Exponential patterns for pH and EC, respectively, underscoring the
complex spatial variability of these parameters within cultivated sites.
Similarly, in El Outaya, granulometry analysis showcased sandy loam soil dominance, with pH
values exhibiting a similar range as in Ourlal. Salinity levels in irrigation water were also
noteworthy, with EC values indicating high salinity in cultivated soils and moderate salinity in
reference soils. Total limestone measurements confirmed a strongly calcareous character across
all sites, accompanied by low organic matter content. The coefficient of variation highlighted
minimal spatial variability in organic matter content but significant fluctuations in EC and total
limestone values across study sites.
Overall, these findings underscore the profound impact of agricultural practices on soil
characteristics in both Ourlal and El Outaya, emphasizing the necessity for improved management
strategies to ensure the long-term sustainability of farming systems in irrigated regions. By viii

leveraging geostatistical techniques and interdisciplinary insights, future endeavors can further
elucidate the intricate dynamics shaping soil quality, paving the way for more informed decision-
making and sustainable agricultural practices in challenging environments like the Algerian Sahara