Hydromulch history, trials, and challenges—a review

Abstract Every year agriculture uses 2 million tonnes of plastic mulch in the form of polyethylene (i.e., “PE mulch”) to grow the world’s food. Plastic mulch is a key tool for growers to suppress weeds, improve crop microclimates, increase yields, mitigate erosion, and potentially enhance crop quality. However, plastic mulch use comes at a major environmental cost due to poor end-of-life outcomes. Hydromulch (also known as “hydramulch” or “hydro-mulch”) is an alternative, sprayable, soil-biodegradable mulch technology made from biobased feedstocks that can be formulated to be acceptable in certified organic agriculture in the United States and Canada. Paper-based hydromulches are generally made from some combination of recycled cellulose fiber, water, tackifier or other binding agents, and sometimes filler derived from various agricultural residues or waste products. The objective of this review is to provide a historical overview of hydromulch, highlight key findings from previous hydromulch research, and provide recommendations to advance the use of hydromulch as a biobased, soil-biodegradable alternative to plastic mulches in specialty crop agriculture. Feedstock and application costs are still major barriers for commercialization and may be mitigated by further research, including the creation of hydromulch formulations that utilize agricultural residues without compromising the physical properties of the mulch layer. Overall, this literature review indicates that hydromulch is a promising technology, but also one in need of further research to be viable across a broad spectrum of cropping systems and environments.