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As a creative and agile Iranian holding in the bitumen industry, DEJPA is among the first three producers in Iran with an export market, focusing on the field of bitumen and mulch. It is also known as a leading company in the field of technical and engineering services in the oil refining, bitumen and mulch industry, and it has made successful entries in the field of oil refining as business opportunities for the coming years.
Taking the lead in gaining market share in the current chain through increasing productivity, intelligence and innovation in supply, production and sales methods, as well as entering the oil refining chain in order to learn and build strategic capacity for the future of business.
40 YEARS OF COUNTINUES ACTIVITY IN BITUMEN PRODUCTION.
 
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Dejpa Bitumen

Evaluation of Oil Mulch Effect on Wind Erosion Threshold Velocity and Some of Soil Properties (Case Study: Dehloran, Ilam)


This study investigates the effects of oil mulch on wind erosion control and soil properties in the Abu-Ghoveir area of Dehloran, Ilam. Following mulch application, soil samples were collected monthly over a year from three treatments (mulched, control, and afforestation) at two depths (0–10 cm and 10–50 cm). Soil parameters, including temperature, moisture, pH, electrical conductivity (EC), organic matter (OM), sodium (Na), and sodium adsorption ratio (SAR), were measured. Wind erosion threshold velocity was also determined using a wind tunnel. The findings revealed that oil mulch significantly influenced certain physical and chemical soil properties and effectively increased the threshold wind velocity. The optimal mulch application rate was estimated at 7 tons per hectare. Oil mulch application reduced evaporation, increased surface soil moisture, and provided a suitable substrate for the recovery of native vegetation in arid regions.
Dejpa Bitumen

Interaction of Petroleum Mulching, Vegetation Restoration and Dust Fallout on the Conditions of Sand Dunes in Southwest Iran


This study investigates the long-term effects (5, 20, and 40 years) of petroleum mulching and biological fixation (PM-BF) on the chemical, physical, and mineralogical characteristics of stabilized sand dunes in Khuzestan Province, Iran. The results revealed that PM-BF significantly improved vegetation cover and enhanced soil properties such as organic matter, cation exchange capacity, clay content, and electrical conductivity. However, petroleum mulch introduced heavy metals (Ni, Cd, Pb), which peaked in younger PM-BF regions but gradually decreased over time due to leaching. Dust fallout also contributed to the formation of specific clay minerals such as palygorskite and smectite. Although PM-BF supports ecosystem recovery and reduces dust-related impacts, the potential accumulation of toxic metals raises concerns for agricultural and environmental uses.
Dejpa Bitumen

Diversity and Composition of Vegetation and Soil Seed Banks After Sand Dune Restoration by Oil Mulching and Plantations

The soil seed bank (SSB) is a valuable reservoir of seeds hidden in the soil, playing a crucial role in vegetation establishment under adverse environmental conditions. However, limited knowledge exists regarding the effects of restoration measures on SSB, particularly in arid ecosystems. This study examines the impacts of oil mulching (1 and 3 years after application) and plantations (15-year-old) on the diversity and composition of SSB and aboveground vegetation (AGV) compared to non-restored areas. The results indicate that species richness was low in the studied area (36 species from 16 families), with SSB contributing less than AGV (11 and 34 species, respectively). The highest number of exclusive species was observed in the plantation treatment, while the lowest was recorded in the 1-year mulching treatment. The diversity indices revealed that the highest values occurred in the plantation and 3-year mulching plots. Seed density was significantly greater in the plantation area compared to the other treatments. The analysis of plant composition demonstrated that the plantation treatment was distinct from other treatments, with the 3-year mulching site being the closest to it. These findings suggest a trade-off between the short-term and long-term effects of oil mulching, where initial negative impacts diminish over time, leading to positive ecological outcomes. Ultimately, oil mulching, in combination with afforestation, fosters a favorable microclimate, improving AGV and SSB diversity and composition.