Agricultural residues are generated during the production and processing of agricultural crops. Under modern date palm plantation practices, field operations generate huge quantities of residues, which are discarded with little valorization. The date palm agro-industry produces significant amounts of waste. The accumulation of these residues can cause ecological damage to the oasis ecosystems. There is a lack of comprehensive data on long-term research studies that aim to assess the impact of date palm waste management practices. Composting and/or pyrolysis of date palm residues showed benefits for improving soil physical and chemical properties, particularly in sandy soils. This claim holds particular significance for arid and semi-arid regions, which are characterized by low fertility and are susceptible to soil degradation, accentuated by ongoing climate change. This review summarizes the existing literature concerning the valorization of date palm residues with regards to compost and pyrolysis processes, as well as the impact of their application on soil quality. Further research is required to assess the effects of using date palm residues for better soil amendment management. Research should focus on composting and biochar technologies for date palm residues and their application in arid and semi-arid regions to combat soil erosion and degradation. Increasing the beneficial uses of date palm residues could lead to sustainable and economic growth in dry areas.

Generally, soils of arid and semi-arid regions have low water retention properties due to high sand and low organic carbon contents. This study aimed at quantifying the effect of date palm-based organic amendments (OAs) on the water retention properties of two soils (sandy loam and silty loam), as well as the influence of sand supplementation (0.5–2 mm) on the magnitude of the effect of OAs. Different grain size distributions were obtained by adding sand to natural soils. For this purpose, sand was added to the two soils (1/3 and 2/3) and different soil-OA combinations were tested at a dose of 3% by mass: compost alone, biochar alone and a mixture of biochar and compost (50:50 in mass), in addition to unamended control soils. Soil water contents were measured at nine matric potentials ranging from the saturation to the permanent wilting point. Biochar was more efficient than compost at improving soil water retention. The effect of organic amendments on water retention increased with sand content. In most cases, soil water content values were significantly higher for biochar-amended soils than for unamended or compost-amended soils. The weakness of the effect of compost addition (if alone) was probably due to its properties and notably its high mineral content and electrical conductivity. Soil sand supplementation led to higher differences between the OA-amended soils and unamended soils. Changes in available water capacity reached +26% and +80% in a sandy loamy soil enriched with 2/3 sand and amended with compost and with biochar, respectively, compared to the unamended soil. These results show that sand content (and more generally, soil texture) influences the effect of OA application. Thus, the application of biochar from date palm residues in soil seems to be an effective solution to improve the water retention properties of coarse textured soils and contribute to optimizing the use of water resources in irrigated areas.

Gypsum is the most abundant mineral in the soils of arid regions, it forms when the concentrations of Ca+2 and SO4-2 are considerable in the soil and has an enormous influence on their physico-chemical properties. Several representative profiles on a sequence in the Ziban region (northeast of Algeria) were studied. The results obtained indicate that several forms of gypsum are distributed according to the physico-chemical characteristics of the soils. The formation of gypsum is geological in the upper levels and of neoformation in the lower part of the plain towards the depression of Oumach this is due to the proximity of the water table.

During this study, our objective was to systematically identify predominant spatiotemporal trends related to the evolution of agricultural perimeters in a Saharan region, specifically the oases of Oued Righ in Algeria. To achieve this, we used satellite imagery data. The chronological sequence of satellite images covering the Oued Righ region, situated in the Northeastern Sahara of Algeria, was meticulously established. Spatial remote sensing proved to be an essential tool, providing us with up-to-date and geo-referenced data regarding vegetation. We used a time series of Landsat (8, 4-5, 7) and Sentinel 2 images covering Oued Righ from 1984 to 2024, using bands 4, 3, 2, and 5, 4, 3 infrared. These images offered precise insights into the actual vegetation development in the study area, eliminating any guesswork. Our analysis relied on vegetation indices, notably the NDVI (Normalized Difference Vegetation Index), allowing us to objectively and scientifically monitor the evolution of this perimeter.