Agricultural plastic mulch made from non-biodegradable polyethylene (i.e., “PE mulch”) provides many horticultural benefits. However, PE mulch requires annual removal and disposal, which generates large volumes of plastic waste that is rarely recycled and can become a pollutant. Incomplete removal of PE mulch also can leave behind plastic fragments that threaten soil and ecosystem health. To address these challenges, soil-biodegradable mulches (BDMs) have emerged as a potentially more eco-friendly alternative. BDMs are designed to provide the same advantages for specialty crop production as PE mulch and naturally biodegrade when incorporated into the soil. In addition, non-biodegradable reflective mulch has emerged as a promising mulch technology that may reduce key insect pests. The objective of this research was to evaluate the impacts of different mulch technologies, including soil-biodegradable and reflective mulches, on horticultural and pest dynamics in day-neutral strawberry (Fragaria×ananassa cv. Albion) in northwest Washington. Seven mulch treatments were established in a randomized complete block design with four replications in 2023. Treatments included green and black BDM made with ecovio and Mater-Bi feedstocks, non-biodegradable metalized mulch, and controls of black PE mulch and unmulched plots. Yield from all mulch treatments did not differ significantly from black PE control except for the green BDM made with ecovio feedstock. The green BDM made with ecovio resulted in significantly lower (32%) yield, similar to unmulched control. Lower yield may be attributed to the rapid deterioration of the green BDM treatments, which lacks carbon black and deteriorated more rapidly compared to other mulch treatments. However, black BDM made from MaterBi feedstock and metalized mulch were 37% and 11% less deteriorated than PE control respectively. Additionally, all mulch treatments suppressed weeds better than the unmulched control and were not different from black PE mulch. Aphid and thrips populations were highest in unmulched plots, whereas metalized mulch had fewer thrips (on sticky cards) and fewer aphids (on leaves) than all other treatments. Overall, the study highlighted that black BDM performs similarly to PE mulch with regards to potential weed suppression and maintenance of yield, whereas the rapid deterioration of green BDM could effect the soil microclimate and subsequent plant growth. Despite rapid mulch deterioration, the study did not observe compromised weed management. Metalized mulch may contribute to reducing pest populations but impacts on pollination and biological control remains unknown. Additional research on soil health effects is required given the fate of BDMs is in-soil incorporation.
