Living Mulch with Selected Herbs for Soil Management in Organic Apple Orchards

Summary

The establishment of living mulches in organic orchards could potentially improve the
orchard biodiversity and, when specific plant species are selected, provide additional eco-services
and functions, including adequate weed management. This study was conducted in an organically
managed apple orchard in Skierniewice (Poland) to assess the effect of two selected living mulching
species: Alchemilla vulgaris and Mentha piperita. They were assessed on weed control, weed biodiversity,
tree nutritional status, root dry weight density (RDWD), and other root morphological traits
compared to a natural soil cover (control). Overall, both living mulches produced 42.5% more dry
biomass, increased weed species number (+29%), and increased soil coverage (+33%) compared
to control mowed plots. The apple leaf chlorophyll index and nutrient content were higher in the
presence of both living mulches than in the control. In addition, apple trees had 30–46% higher root
dry weight densities, even though other root morphological traits were not affected by the treatments.
The results suggested that the tree row can be managed with living mulches of herbs; these species
have the potential to provide an additional income to the farmer, as well as beneficial effects for the
orchard biodiversity, without impairing the tree root development and nutrient status.