Growing Legumes in Orchard Alleys as an Internal Nitrogen Source

Abstract

<jats:p>The drive alley in modern apple (<jats:italic>Malus</jats:italic> ×<jats:italic>domestica</jats:italic> Bork.) orchards often receives enough light to grow plants other than the typical perennial grass cover. By planting leguminous species in this area, it is possible to produce a portion of the nitrogen needs of the orchard by mowing the vegetation and blowing it onto the tree row where it mineralizes and releases available N over the tree roots. Four perennial legume species [alfalfa (<jats:italic>Medicago sativa</jats:italic> L.), ladino white clover (<jats:italic>Trifolium repens</jats:italic> L.), birdsfoot trefoil (<jats:italic>Lotus corniculatus</jats:italic> L.), kura clover (<jats:italic>Trifolium ambiguum</jats:italic> L.)] were compared with the resident grass cover crop in a mature apple orchard. All legumes were direct-seeded into the alley to avoid any soil disturbance and were successfully established. Legume biomass and tissue N were monitored, along with biweekly monitoring of tree row soil nitrogen with both soil sampling and ion exchange resins using Plant Root Simulator<jats:sup>®</jats:sup> probes. Four mowings of alfalfa contained ≈43 kg total N/ha that was added to the tree row during the second season (2009), with a dry matter C:N of 10.8. Economically, legume nitrogen appears to be less expensive than other sources of organic N and may be cost competitive with synthetic fertilizer N when prices are high.</jats:p>

Managing Floral Resources in Apple Orchards for Pest Control: Ideas, Experiences and Future Directions

“…Typical cover crops are uniform; there exist cover crop cultivars that are the product of intensive efforts of selective breeding and seed production. Weed control and tree nutrition by cover crops are important aspects in orchard systems, especially in organic production, where synthetic fertilizers and herbicides are not allowed [34,35]. Besides these aspects, cover crops may also contribute to better pest management due to altered host plant nutrition or microclimate in orchards as well as by providing essential resources (shelter, alternative prey, nectar, and pollen) to benefit natural enemies [17].…”

“…Legumes, like faba bean ( Vicia faba L.), other Vicia species, clover or alfalfa grown as a cover crop in orchards are often introduced because they may provide several ecosystem services like fertilization, prevention of soil erosion, alternative prey ( Aphis fabae Scopoli) and flowers. [17,34,35]. Moreover, vetches (e.g., Vicia sepium L. and Vicia sativa L.,) offer carbohydrates in plant sap from special structures, so-called extrafloral nectaries (EFN) [45] in addition to floral nectar (Figure 2a).…”