This is the VOA Special English Agriculture Report.
is a plant considered a weed? Experts at Penn State University have a simple
answer: When its undesirable qualities outweigh its good qualities.
Consider this: Crops generally produce several hundred
seeds per plant. But each weed plant can produce tens or even hundreds of
thousands of seeds. And some buried seeds can survive up to forty years, or
weeds means that you have to remove all the seeds and roots so the plants will
not grow back. But birds or the wind can reintroduce them to the land.
more common way to deal with weeds is to control them enough so that the land
can be used for planting. Experts advise using two or more control methods to
deal with weeds.
killers or natural treatments like corn gluten can suppress weed growth. Dense
planting of a crop can also act as a natural control.
Curran is a professor of weed science at Penn State, in University Park,
Pennsylvania. He says one of the most common methods for suppressing weeds is
says a dense, competitive crop that quickly shades the soil will help suppress
many weeds. The seeds need light to grow, so blocking the sun will reduce weed
controls include turning over the soil, pulling the weeds by hand or covering
them with mulch made from wood, garden waste or other material. Mulch is widely
used, but even mulch has its limits.
resource specialists in the Queensland government in Australia note that weeds
can be transported in mulch. This is also true of soil, grain, hay and animals.
animals like sheep or goats can provide a biological control -- they eat weeds.
Insects and other organisms can also act as biological controls.
Preventing the spread of weeds is an
important part of weed management. Farm vehicles should be kept out of areas
with weeds. If that is not possible, then clean off the equipment and your
shoes when leaving.
People in Queensland are advised to take weeds and
garden waste to a waste center or burn them, bury them deeply or make them into
Curran says composting weeds is another way to make use of them. The process of
making organically rich compost produces heat. The heat will kill many, though
not all, weed seeds. The same is true of seeds that pass through farm animals
that graze on weeds.
And that's the VOA Special English
Agriculture Report, written by Jerilyn Watson. Archives are at
voaspecialenglish.com. I'm Steve Ember.