Living mulch persistence in an apple orchard and its effect on the weed flora in temperate climatic conditions

Abstract

AbstractReplacing herbicide fallow with alternative floor management can conserve soil and reduce agrochemical use in an orchard. Increased perennial weed resistance to foliar preparations has recently become an additional motivation to abandon herbicides. This study explores apple tree understory weed flora alteration after introducing Festuca ovina living mulch to the rows. Delayed cover crop sowing was tested as a possible approach to address the problem of high perennial weed dominance when a living mulch is introduced in the year of orchard establishment, in addition to reducing competition. The effect of replacing the M.9 dwarfing rootstock with the M.26 and P 60 semi‐dwarfing rootstocks to foster tree competitiveness was also investigated, and the influence of the mulch dominance on apple yield was analysed. Abundant perennial weed flora developed in the living mulch regardless of the mitigation strategy, and one of the cover crop cohorts exhibited unsatisfactory persistence when maintained under trees on P 60. This pattern was attributed to an interactive effect of shadowing by the more vigorous trees and by Glechoma hederacea and Artemisia vulgaris weeds, which abounded due to insufficient mowing frequency. More intensive tree understory management is recommended, especially in semi‐dwarf orchards, and G. hederacea should be studied more as a candidate mulch species, potentially superior to F. ovina.