Blogs

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.

The impact of oil mulch on seed germination and the establishment of seedlings and cuttings has always been a question associated with its use. The aim of this study was to evaluate the efficiency of the polymer Poly-Lattice in seed germination and plant establishment and compare it with oil mulch. For this purpose, the study was conducted in two phases: greenhouse and field experiments.

In the greenhouse experiments, the effect of this polymer compared to oil mulch on the germination and establishment of Haloxylon seeds was examined using a completely randomized design with four treatments (oil mulch, Poly-Lattice solution with water, Poly-Lattice mixed with sand, and control) in three replications. Three weeks after planting, the lowest germination rate was observed in the Poly-Lattice-sand mixture treatment (a slurry with a thickness of 2 to 3 mm), while the highest germination rate belonged to the oil mulch treatment.

Meanwhile, in the field experiment, Poly-Lattice did not show a significant difference from oil mulch in the establishment of planted seedlings and cuttings. However, the average measured traits indicate that the percentage of seedling and cutting establishment was significantly higher in the oil mulch treatment compared to other treatments. This can be attributed to the better stabilization of the area by oil mulch.

This article investigates the impact of oil mulching with petroleum products on water quality. Oil mulch, composed of heavy petroleum byproducts, has the potential to contaminate water resources with heavy metals and hydrocarbons. The study examined oil mulch samples from various regions in Khuzestan Province over short-term, medium-term, and long-term periods, as well as samples from the Abadan refinery under laboratory conditions simulating natural environments with a 24-hour contact time with water. The results revealed that oil mulch does not significantly increase water pollution in terms of heavy metals, and the levels of hydrocarbons detected were below permissible limits. The study concludes that while oil mulch may contribute to minor increases in certain pollutants, it does not pose a significant threat to water quality in terms of heavy metals and hydrocarbons.

This article investigates the effects of petroleum mulch on vegetation and soil in the sandy deserts of Samad Abad, Sarakhs, in Khorasan Razavi province. Petroleum mulch is a common method for stabilizing mobile sands in Iran, but its effects on vegetation and soil have been less studied. In this research, sampling was conducted in both mulched and control areas to assess vegetation cover and soil attributes. The results showed that while there was no significant difference in total vegetation cover and the density of dominant species such as Astragalus squarosus and Convolvolus hamadae between the mulched and control areas, the total volume and green matter of plants were significantly higher in the mulched area. Additionally, the organic matter content in the soil at a depth of 20-80 cm was significantly higher in the mulched area compared to the control. These findings suggest that petroleum mulch can improve plant growth conditions and increase soil organic matter.

Mulching is an effective method for stabilizing sand dunes and supporting afforestation and desertification control projects. Oil mulch enhances soil quality by adding essential minerals and increasing soil porosity, which improves water infiltration and retention. It also helps maintain soil moisture by preventing rapid evaporation. By creating a sticky layer on the soil surface, oil mulch stops the movement of sand dunes and creates favorable conditions for plant growth. Additionally, it stabilizes soil temperature, delaying the freezing of plant seeds in winter. This article examines the positive effects of oil mulch on soil quality, plant growth, and sand dune stabilization.

This article compares the effects of oil mulch, non-oil mulch (such as Chinese mulch made from recycled plastics), and moisture absorbent materials (from Belgium and France) on the germination of four plant species (Calligonum comosum, Cyperus conglomeratus, Smirnovia iranica, Haloxylon aphyllum) and the stabilization of shifting sands in desert areas. The results show that oil mulch has a significant impact on germination at 1% and 5% levels, outperforming other methods due to its resistance to regional winds, which minimizes seed displacement.

The study used a split-plot statistical design, and data were analyzed using SAS software. The findings indicate that oil mulch is the best option for creating a germination-friendly environment under natural conditions (considering rainfall and wind patterns). Additionally, seeds of Haloxylon and Smirnovia showed the highest germination rates.

Recommendations include further investigation into the use of moisture absorbent materials for stabilizing potted seedlings, increasing the concentration of Chinese mulch to enhance its effectiveness, and documenting the impact of oil mulch during the seed establishment phase.

The November 1979 issue of National Geographic highlights Iran’s use of oil-based mulch to stabilize shifting sand dunes near Ahvaz. This method reduced sandstorms and enabled reforestation in the desert.

This study investigates the long-term effects of oil mulch on biodiversity indices of soil macrofauna and vegetation in the Jask region. Results indicate that oil mulch significantly increases the richness and diversity of soil macrofauna but has no significant impact on plant diversity after 10 to 14 years.

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.