This 2009 study by Harper and Ferguson, published by Cambridge University Press, evaluates the impact of petroleum mulch and sowing time on the establishment and yield of oilseed sunflower (Helianthus annuus L.). Results showed that petroleum mulch enhanced seedling establishment, conserved soil moisture, improved plant resilience under stress, and reduced weed competition. Additionally, optimal sowing times significantly influenced plant growth and yield. The combined use of petroleum mulch and appropriate sowing time led to notable yield improvements, offering a sustainable strategy for sunflower oil production.

This three-year study conducted in Mississippi evaluated the effects of petroleum mulch on soil temperature, seedling emergence, weed control, and cotton yield. The findings revealed that petroleum mulch increased soil temperature in the germination zone, reduced soil crusting after rainfall, improved plant stands, and significantly boosted cotton yield—especially when applied in 6-inch wide bands. Combining the mulch with preemergence herbicides like trifluralin further enhanced weed control. However, the practical challenges of cost, handling, and application at scale remain important considerations.

This study investigates the impact of petroleum mulch combined with preemergence herbicides (diuron, prometryne, CIPC, and DCPA) on weed control, soil moisture, temperature, and cotton yield. Results showed that petroleum mulch, especially when used with herbicides, significantly reduced weed growth, preserved soil moisture, regulated soil temperature, and improved cotton yield. The findings recommend integrated use of petroleum mulch and herbicides as an effective strategy for optimizing cotton production under challenging climatic conditions.

The effects of ‘Colas’ bitumen emulsion on soil temperature, soil moisture and the stability of soil structure were determined in temperate and tropical conditions.
At a depth of 5 cm, soil temperature increments of from 2°c in England to 8°c in Trinidad were recorded when the soil was mulched with bitumen. Temperatures under bitumen were shown to be higher than those under mulches of black polyethylene, sand or pine needles, and in unmulched soil. It was also shown that growing crops exerted an increasing shading effect which limited the period of effectiveness of a mulch. When the mulch is applied in bands, these should be at least 15 cm wide for maximum temperature increments to occur.
Soil moisture studies were conducted both in the field and under laboratory/glasshouse conditions. It was found that only comparatively thick mulches on smooth soil surfaces, caused any appreciable reduction in water losses through evaporation.
It was found that the crumb structures of soils treated with very thin bitumen mulches (∼150μ thick) were able to withstand considerably more weathering by rainfall or irrigation than unmulched soil before breakdown of the soil surface structure occurred.

This study examines the effects of various Iranian petroleum-based mulches on soil surface evaporation. The findings reveal that these mulches significantly reduce water loss through evaporation, especially in arid and semi-arid regions. By forming a protective layer over the soil, petroleum mulches help retain moisture and enhance soil resilience under harsh climate conditions. The effectiveness of the mulch depends on factors such as mulch type, application thickness, and soil characteristics.