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The relationship between a cover of four grass living mulches in an apple orchard and the weed cover as well as its impact on the fruit tree yield, growth, and fruit quality was estimated at the Fruit Experimental Station of the Wrocław University of Environmental and Life Sciences in Wrocław (Poland). The experiment was established in a young orchard of ‘Chopin’ cv. apple trees graed on rootstock MM 106, i.e. one of the strongest semi-dwarf rootstock. One year aer, the tree planting soil was covered by blue fescue, red fescue, Kentucky bluegrass, and perennial ryegrass in tree rows and tractor alleys. The apple trees showed a similar degree of adaptation to the changing cultivation conditions in four different living mulches despite the varied share of the area covered by weeds. However, they did not avoid competition from different grass sods and their weediness, which was reflected in their low yield and low crop efficiency coefficient. The perennial species composition and the percentage share of the most common weeds differentiated the sod of the studied grasses. Among several perennial weed species, Trifolium repens L. was found to be the most competitive in all grass living mulches. The dynamic development of this species in time was stimulated by a rapid increase in precipitation in the orchard. The lowest soil surface cover by the total weeds was noted soon aer the perennial ryegrass emergence due to the rapid development of the grass. Red fescue spread the most efficiently among all the studied grasses, and its coverage allowed effective reduction of the presence of weeds. This cover crop also maintained high purity of grass sod, especially in the tree rows, until the end of the experiment period. [ABSTRACT FROM AUTHOR]

Replacing 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. [ABSTRACT FROM AUTHOR]

The durability of four grass living mulches, population of annual and perennial weeds, and their biodiversity in tree rows and tractor alleys were evaluated in the first 4 years after cover crop sowing. The experiment was established in a young semi-dwarf apple orchard 1 year after the planting of the tree 'Chopin' cv. Soil coverage was satisfactory for the three cover crops: red fescue, Kentucky bluegrass, and perennial ryegrass. The sods of the grasses exhibited 100% soil surface cover in the tree rows and drive alleys, starting from 1 year after sowing to the end of the study period. Only the maintenance of the blue fescue resulted in low average soil development. Annual and perennial weed populations were lower in the tree rows than in the drive alleys. It was determined meticulous and manual soil preparation prior to all grass sowing under tree crowns, followed by precise mowing of grasses and nitrogen fertilization in subsequent years. The highest soil surface cover by the total annual taxa was observed immediately after the emergence of the living mulch. Total perennial weed populations increased in the following vegetation seasons. Trifolium repens L. and Taraxacum offcinale (L.) Web. dominated all the grass living mulches evaluated. Only the red fescue sod effectively limited the infestation of perennial weed after 4 years of living mulch maintenance in the tree row. More than half of the annual and perennial weed taxa occurred sporadically in all living mulches. In both the tree rows and tractor alleys, the soil surface cover was not more than 1%, and these species contributed to the increase in orchard biodiversity. [ABSTRACT FROM AUTHOR]