Agriculture Reference
In-Depth Information
planted in a strip 3 to 4 feet wide. At the edges of the rows where the al-
ley and in-row cover crops meet, a narrow strip of bare soil is maintained
third spring after planting your trees before establishing the in-row living
mulches.
In extensive orchard floor management trials, Washington State
University scientists examined the sandwich system in a newly planted or-
ganic apple orchard. The sandwich system was compared with clean-cul-
tivated, wood-chip-mulched, and other living mulched tree rows. Results
showed that there was less competition between weeds and young trees in
the sandwich system than in a living mulch system that completely covered
the orchard floor.
Although weeds were reported as being abundant in the rows mulched
with wood chips, those trees produced good growth during their first 2 years
in the field. The in-row clean cultivation treatment produced the lowest weed
competition and also produced good tree growth, but it disrupted the tree
root systems and caused the trees to lean. In the trials, both the wood chip
and the clean cultivation treatments produced greater tree growth than the
sandwich system.
Although the in-row living mulches (a.k.a. in-row cover crops) showed
promise for controlling weeds and enhancing soil fertility and overall quality,
they competed with the fruit trees, reducing tree growth. Rodents were a
problem in the living mulches and represent the greatest challenge to the use
of in-row living mulches. In the Washington trials, sweet woodruff (
Galium
odoratum
) had significantly lower meadow vole infestation than the other
crops tested, possibly due to the coumarin found in sweet woodruff. Japanese
pachysandra (
Pachysandra terminalis
) has also proven somewhat repellent
to rodents due to the presence of steroidal alkaloids.
How to use.
We are clearly at the beginning of developing and understand-
ing in-row living mulch cover crops. While they show great promise, as does
the sandwich system, use them with caution. A leading tree fruit research-
