Print ISSN: 2077-5822

Online ISSN: 2618-1479

Keywords : Geostatistics

Spatial Variability of Soil Properties in Palm Groves of the Central Algerian Sahara (Case of Zelfana)


Al-Qadisiyah Journal For Agriculture Sciences, 2022, Volume 12, Issue 1, Pages 48-57
DOI: 10.33794/qjas.2022.132994.1028

Monitoring soil quality in irrigated areas is essential for assessing the sustainability of production systems. In this respect, the spatial variability of the properties of irrigated soils is a mean to know the evolution of the latter. This study aims to determine the spatial variability of soil organic matter, salinity, pH and active limestone using a geostatistical approach. The present study was carried out in the region of Zelfana located in the Algerian central Sahara, the samples were collected from a depth of 0 to 30 cm and analysed for organic matter, salinity, pH and active limestone. The analytical results show that the soil is very poor in organic matter, very salty, alkaline to very alkaline and moderately calcareous. The geostatistical analysis revealed various patterns and levels of spatial distribution of the studied properties. The results showed a weak spatial dependence for organic matter, moderate for pH and salinity and strong for active limestone. The variographic analysis showed that the nugget effect is weak for organic matter and pH, moderate for salinity, while active limestone does not show a nugget effect. The range varies from 75 meters for salinity to 299 meters for organic matter, confirming the validity of the adopted sampling and allowing the optimization of future sampling plans. The Arcgis autoKriging function was used to select the best theoretical variogram model from those most commonly used in geostatistics (Gaussian, spherical, exponential and circular). This model was used to produce the spatial variability maps using ordinary kriging. Spatial variability of soil properties is influenced by agricultural intensification, something that must be taken into consideration for integrated and sustainable land management in similar regions.

Improvement of Interpolation Using Information From Rainfall Stations and Comparison of Hydroclimate Changes (1913-1938)/(1986-2016)

Hakim Bachir; Souheila Kezouh; M‘hamed Ait-oubelli; Ahcène Semar; Dalila Smadhi; Karim Ouamer-ali

Al-Qadisiyah Journal For Agriculture Sciences, 2021, Volume 11, Issue 1, Pages 54-67
DOI: 10.33794/qjas.2021.129350.1002

The primary objective of this study is to use a better method for rainfall mapping in areas with low density rain gauge networks. Secondly, to identify and study hydro-climatic change in the semi-arid high plains of eastern Algeria on the basis of a comparative mapping approach. The latter concerns the annual rainfall map produced by the authors of this paper for the period studied (1986/2016) and the annual rainfall map for the period 1913/1938, prepared by Chaumont and Paquin (1971). The results of this analysis show that isohyets between 300 mm and 350 mm cover a large part of the study area, they occupy an area of 14444 Km², followed by isohyets between 200 mm and 300 mm with an area of 5298 Km². In addition, the comparative analysis between the periods showed that hydro-climatic change was clear for the 200 mm, 300 mm and 400 mm isohyets, whereas there are no major changes for the 500 mm and above isohyets. Data processing based on a combination of statistical and geostatistical analysis (multiple linear regression and kriging) has once again shown the value of taking into account other parameters in the design of rainfall maps, such as geomorphological and geographical parameters.