Agriculture Reference
In-Depth Information
mains the standard practice in conventional orchards today. Other benefits
are reduced erosion and soil compaction, better access during wet weather,
more soil organic matter, and a larger habitat for beneficial organisms.
As commercial organic orchards increased in size and number, it became
more important to find cost-effective weed control methods. By studying the
problem and testing different weed control strategies, we began to discover
advantages in maintaining rather diverse vegetation on orchard floors. While
it is relatively easy to manage alleyways in both organic and convention-
al systems, it is much more difficult and expensive for commercial organic
growers to manage vegetation within tree rows.
Planting fruit trees into dense vegetation of any kind generally causes
poor tree survival rates, and those trees that live are often stunted and un-
productive. For that reason, it is important to eliminate, to the greatest de-
gree possible, competitive plant species before planting your trees. Serious
orchard weeds vary across the country, but they typically include aggressive
perennial species such as quack grass, Bermuda grass, johnsongrass,
nutsedge, bindweed, and Canada thistles.
Organic Herbicides and Thermal Controls
For many organic growers, bringing weeds under control before planting is
the most difficult step in developing an orchard and requires varied cultur-
al practices. Serious infestations of perennial weeds are hardest to control.
Unfortunately, organic herbicides, including soaps, essential oils, and vinegar,
are largely ineffective in controlling established perennial weeds. The same
limitation applies to thermal weed control methods, such as flaming, infrared,
and infrared plus steam. Only plant tissues directly contacted by the herb-
icides or heat are killed, and perennial weeds quickly resprout from under-
ground organs. Thermal weeding and organic herbicides can be helpful in
controlling annual weeds and young seedlings of perennial weeds.
