Synthesis of current evidence on factors influencing the suitability of synthetic biodegradable mulches for agricultural applications: A systematic review

Mulching practice offers farmers an opportunity to minimize the effects of drought, water loss, and soil erosion on crop production. Plastic film is widely used as a mulching material; however, contamination of arable lands by residual plastic has become a serious concern. Synthetic biodegradable mulch films and sprays may offer a more sustainable alternative to plastic films, however current evidence on the factors that influence the suitability of these products for agricultural applications is fragmented, making it unclear under what conditions these products meet agronomic, environmental, and societal needs. We address this gap by conducting a systematic review of studies that evaluate the use of synthesized biodegradable mulch for agricultural applications and extract data from 151 primary studies on factors that directly and indirectly influence the suitability of its use. Like others, we find that using biodegradable mulches nearly always provides agronomic benefits over not mulching but rarely provides agronomic benefits over conventional plastic films. However, we also find that reported benefits vary across climate conditions, mulch type, and crop and agronomic factors tested, highlighting the context-specificity of biodegradable mulch benefits which is not yet well understood. In addition, we identify a need for studies that experimentally evaluate the secondary environmental and social benefits of biodegradable mulch use to provide a better understanding of the full potential of these products for sustainable agriculture.