Coloured plastic mulches: impact on soil properties and crop productivity

Mulches are materials applied in a soil surface for different roles and purposes. Plastic mulches with different colour have been developed and utilized in different crop production systems. Using coloured plastic mulches is mainly focused in modifying the radiation budget and decreasing the soil water loss. Besides, it helps to regulate soil temperature, water use efficiency, plant growth, yield, quality and weed and insect infestation. In this review, the knowledge and possible application of coloured plastic mulches, which can improve the soil physical properties, growth, yield, and quality crops has been reviewed and discussed. The role of coloured plastic mulches to mitigate the harmful effect of environmental stress in crops is also examined. Various physicochemical processes leading to improved crop production under the effect of coloured plastic mulches are also discussed. The combined results indicated that, effect of coloured plastic mulches is highly significant on soil temperature, moisture and water holding capacity. While black and blue plastics increase soil temperature, clear and white decreases it. Higher number of fruits, number of roots, tubers and bulbs was recorded in use of coloured plastic mulches. Similarly, the TSS, Vitamin C and juice percentage of different plants also showed significant improvement. It is also reported that weed infestation and viral diseases is highly reduced. Coloured plastic mulches also have some negative impacts like, decrease growth and yield in some plants, increase pest infestation, microplastics contamination, soil puddling, soil structural loss and reduce activity of soil-microorganisms. Therefore, use of coloured plastic mulches require close inspection of interaction with factors like; cropping season, root zone temperature, crop type, insect pest infestation and water use efficiency factors.