October 23, 2014 06:40 UTC

Science & Technology

Getting a Firm Grip on Weed Control

Read, listen and learn English with this story. Double-click on any word to find the definition in the Merriam-Webster Learner's Dictionary.

Chiyoko Kaizuka weeds her spinach field in Moriya, Ibaraki prefecture, Japan
Chiyoko Kaizuka weeds her spinach field in Moriya, Ibaraki prefecture, Japan

Multimedia

Play or download an MP3 of this story
This is the VOA Special English Agriculture Report.
 
When is a plant considered a weed? Experts at Penn State University have a simple answer: When the undesirable qualities outweigh the good qualities.
 
Consider the fact that crops generally produce several hundred seeds from each plant. By comparison, each weed plant can produce tens or even hundreds of thousands of seeds. And some buried seeds can survive up to forty years -- or even longer.
 
Eradicating 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.
 
A 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. 
 
Chemical weed killers or natural treatments like corn gluten can suppress weed growth. Dense planting of a crop can also act as a natural control.
 
Bill 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 dense planting.
 
He 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 growth.
 
Other controls include turning over the soil, pulling the weeds or covering them with mulch made of shredded wood, garden waste or other material.
 
But even mulch has its limits. Natural resource specialists point out that weeds can be transported in mulch. This is also true of soil, grain, hay and animals.
 
Yet animals like sheep or goats eat weeds, so they can provide a biological control. 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.
 
Some people burn weeds or bury them deeply or make them into mulch.
 
Professor Curran says another way to make use of weeds is to compost them. Heat is produced in the process of making organically rich compost to improve soil. The heat will kill many, though not all, weed seeds. The same is true for seeds that pass through animals that graze on weeds.
This forum has been closed.
Comment Sorting
Comments
     
by: Rocío from: Spain
01/27/2013 3:24 PM
My father has a ground with grass and weeds. He is thinking about to boy a coat. After reading this, I am going to encourage him to do it!!

Thanks a lot for your work, it helps me to improve my English.

Learn with The News

  • Armed officers approach Parliament Hilll following a shooting incident in Ottawa, Oct. 22, 2014.

    Video Deadly Attack Shocks Canada's Capital

    Also, Kurdish lawmakers in Iraq vote to send Kurdish forces to the Syrian town of Kobani. China said 43 people tested for possible Ebola infection do not have the virus. Russia and Ukraine are still working to reach an agreement on Ukraine's payments for natural Gas. More

  • Survivors of the Ebola virus pose for a picture outside a clinic near Tubmanburg, October 15, 2014. A total of 4,493 people have died from the world's worst Ebola outbreak on record as of Oct. 12, statistics released by the World Health Organization showe

    Audio Ebola Survivors Speak Out about Their Experience

    The number of Ebola cases continues rising. But there is some hope for those who survive the disease. Recently, a conference for Ebola survivors was held for the first time in eastern Sierra Leone. The goal was to offer advice to survivors and increase understanding of the disease. More

  • FBI Director James Comey speaks about the impact of technology on law enforcement, Thursday, Oct. 16, 2014, at Brookings Institution in Washington.

    Audio Apple, FBI Battle Over Privacy Rules

    Apple recently said it was increasing security settings on its latest operating system for the company’s wireless devices. Apple said its new encryption rules are designed to protect users from search and seizure of their iPhones. But the changes are of concern to federal investigators. More

  • Men convicted of drug related crimes hear the public announcement for their death sentences in Shenzhen, China, on August 15, 1996.  (AP Photo/Vincent Yu, File)

    Audio Activists: China Executed 2,400 People in 2013

    The number of executions in China is lower than in earlier years. However, it is more than three times higher than the number of executions in the rest of the world combined. That information comes from Amnesty International. Death penalty numbers are a state secret in China. More

  • Ebola-CDC brief

    Audio  WHO: Ebola Vaccine Could Be in Use by January

    Also, student leaders in Hong Kong not satisfied with first talks with government officials. North Korea has releases one of three American prisoners. And South African Olympian Oscar Pistorius has been sentenced to five years in prison for the deadly shooting of his girlfriend, Reeva Steenkamp. More

Featured Stories

  • Audio Iron Ships Clash at Sea

    The American Civil War was fought not only on land, but at sea. In 1862, Confederate and Union forces fought a new kind of navy battle in waters off Hampton Roads, Virginia. It was the first battle between iron ships. On the Confederate side was a ship called the Virginia. | The Making of a Nation More

  • Audio San Francisco Radio Stations Ban Lorde's 'Royals'

    The California baseball team, San Francisco Giants, is playing the Kansas City Royals for the 2014 Major League Baseball championship, the World Series. Two radio stations in San Francisco banned the hit song "Royals." In return, another station in Kansas City chose to play the song once every hour. More

  • A neurovascular unit on a chip being developed by Vanderbilt University researchers. (Vanderbilt University Photo/John Wikswo)

    Video Scientists Design Chips to Act Like Human Organs

    Testing new drugs for safety and effectiveness is a costly process in the United States. It also can take a lot of time. Some scientists are now designing silicon computer chips that act like human organs. The scientists think they have found a way to make the process faster and more economical. More

  • Brain Resource Infographic

    Audio Dealing with Distractions and Overreactions

    Five million American children and teenagers have Attention Deficit / Hyperactivity Disorder, commonly known as ADHD. ADHD makes it difficult - if not impossible - to stay with a duty until it is complete. Katherine Ellison knows the problem well. | Health Report More

  • Millions of years of history, which can be found on the ocean floor, are collected and analyzed at the Core Repository in New York.

    Video Scientists Create New Maps of Ocean Floor

    Until recently, scientists had mapped only about 20 percent of the sea floor. But our knowledge of the deep seas is changing because of information from satellites. Scientists have produced a new map that provides a detailed picture of the oceans. More

Practice Your Writing

Confessions of an English Learner BlogConfessions of an English Learner Blog

Tell us About Our Programs