This study addresses the often-competing goals of organic fertility and weed control by evaluating alternative orchard floor
management strategies for their impact on N cycling, tree performance, and soil biological activity in a newly established
apple (
Malus domestica Borkh.) orchard. The standard tillage weed control practice resulted in satisfactory tree growth with desirable levels of
leaf N and most other nutrients; however, soil biological activity did not improve. Maintenance of a living cover understory
increased soil N concentration and availability and improved soil biological activity; however, tree growth was less than
in other treatments likely in response to competition with the living cover understory for space and water. Application of
wood chip mulch resulted in exceptional tree growth which may have resulted from greater water availability, but available
soil N was lower, and consequently, tree leaf N concentration was low; in addition, soil biological activity was not improved.
Clove oil organic herbicide provided poor weed control resulting in lower leaf N and tree growth and did not improve soil
biological activity. Brassicaceae seed meal applications enhanced N availability and soil nematode abundance, but leaf N and
many other nutrients were below desirable levels, and additional research is needed to optimize this treatment. We conclude
that meeting the multiple objectives of weed control, optimal tree health, and increased soil biological activity may require
employment of different orchard floor management strategies at different times during the life of the orchard.
Keywords Living cover mulch - Wood chip mulch - Organic herbicide - Brassicaceae seed meal