This innovative study demonstrates how surface asphalt application to soil can significantly enhance water harvesting and tree growth in drylands.
The technique shows substantial promise in reducing irrigation needs, supporting afforestation efforts, and combating desertification across Iran’s semi-arid regions.

This study evaluates the effects of using petroleum mulch for sand dune stabilization and the potential soil contamination by Polycyclic Aromatic Hydrocarbons (PAHs). Petroleum mulch, produced from heavy petroleum residues, has been widely used in Iran to combat desertification. Soil samples were collected from various regions in three provinces: Khuzestan, Kerman, and Sistan. The PAHs content in soils beneath the mulch layer and in control (non-mulched) sites was measured. The results indicated that the levels of PAHs, particularly Benzo(a)pyrene (BaP), in soils beneath the mulch layer were below the permissible limits set by national standards. Additionally, the penetration of these compounds into the soil depth was minimal, decreasing to 1/40 of the initial amount after several years. Therefore, petroleum mulch and the contaminated soils are considered safe materials.