Evaluation of a Biodegradable and Sprayable Mulch Material for Weed Control in Vineyards and Orchards

Alternative weed management strategies are needed to reconcile the production, health, and environmental goals in agriculture. In this study, a recently developed sprayable self-hardening mulch material based on renewable raw materials (mainly rapeseed oil, starch and sodium alginate) was tested for its potential for weed control in vineyards and orchards. Field trials were conducted in Austria, Germany, and Italy. Weed coverage and biomass were assessed after the application of the mulch material and common in-row weed management practices, namely, herbicide use and mechanical weeding. The present trials showed that the mulch material is largely able to reduce weed growth at a rate comparable to herbicide use and mechanical weeding. The strongest effect on weed coverage was observed shortly after its application (three to four weeks) with a reduction of 83–97% compared with the untreated control. The greatest reduction in biomass was observed in May and June (83–99%). Weed growth then increased to varying degrees depending on the site. The mulch material reached its limits when persistent weeds with extensive root systems (e.g. Cirsium arvense) were prevalent or when high weed pressure was present before the application. For a broader application, optimizations in the use of the mulch material are needed, for example, regarding the application timing and optimal layer thickness. Above all, further development of the application technology and an improvement in cost efficiency are required.