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Cover Crops Are Good for the Soil (and the Farmer)
Written by - Mario Ritter
23 May 2005

I'm Gwen Outen with the VOA Special English Agriculture Report.

Cover crops are an ancient way to help farmers improve their soil, increase their harvests and, these days, save money on chemicals. 

Scientists like Aref Abdul-Baki search for new and better cover crops.  Mister Abdul-Baki is with the Agricultural Research Service of the United States Department of Agriculture.  He works at the Sustainable Agricultural Systems Laboratory in Beltsville, Maryland.

  
Mister Abdul-Baki has found some cover crops to resist groundworms that attack the roots of tomatoes. 

Sunn hemp, cowpea and velvet bean are good for warm, humid areas.  The soil is plowed to plant the cover crops during the summer months.  In the fall, the cover crops are turned over in the soil, then the tomatoes are planted.

In states with moderate climates, like Maryland and Virginia, the cover crops are planted in the fall to grow during early spring.  Mister Abdul-Baki tells us that good cover crops are hairy vetch and rye.

To avoid soil loss, the seeds are planted without the use of plowing.  In May, the cover crops are cut and the remains are left on the surface.  The same method can be used for other summer crops like peppers, sweet corn, green beans and some melons.

After the cover crop is cut, the result is a layer of organic material.  This will help the new crop grow and suppress unwanted plants.  The cover crop provides extra nutrients to the soil.  It also keeps the soil from drying out, and helps prevent the loss of soil.

In hot, dry areas, like in Southern California, cover crops help reduce soil temperatures.  They also reduce water loss and erosion.  Lana vetch is a good cover crop.  It is planted in the fall and breaks down without any assistance.  It releases its seeds back into the soil. 

Mister Abdul-Baki says farmers who use cover crops no longer need to treat their soil with methyl bromide before they plant tomatoes.  Methyl bromide kills many kinds of organisms.  But Mister Abdul-Baki notes that the poison also damages the environment and is a health danger.  The government restricts the use of methyl bromide.  And countries have agreed to a treaty to ban it.

Aref Abdul-Baki says farmers who use cover crops produce as many, or more, tomatoes per hectare as compared to no use of cover crops.

This VOA Special English Agriculture Report was written by Mario Ritter.  Our reports are online at voaspecialenglish.com.  I'm Gwen Outen.

Learning From a Volcano, 25 Years After Mount St. Helens Exploded
Written by - Paul Thompson and Nancy Steinbach
23 May 2005

(MUSIC)

VOICE ONE:

This is SCIENCE IN THE NEWS, in VOA Special English.  I’m Barbara Klein.

VOICE TWO:

 
 
And I’m Doug Johnson.  Twenty-five years ago this month, a volcano exploded in the American state of Washington.  On our program today, we tell about the explosion at Mount Saint Helens and how scientists have improved their knowledge of volcanic activity.

(MUSIC)

VOICE ONE:

May eighteenth, nineteen eighty, was a beautiful Sunday morning in the small town of Ellensburg, Washington.  Fifteen-year-old Scott Johnson was reading a book near his home.   His twelve-year-old sister Leslie was playing with a basketball.  

As Scott read, he looked up to see a huge, black cloud far away to the west.  It might rain, he thought.  Soon, he heard what sounded like a big gun.  The sound seemed to grow louder.  He looked up again.  This time, he saw a huge cloud moving quickly across the sky.  

The two children watched as the sky grew darker.  The cloud began to block light from the sun.  Scott again looked at his book.  He noticed something unusual on the book.  It looked like very fine dust.  How strange, he thought.  It is raining dust!

Scott and Leslie ran into the house and told their parents about what they saw.  They turned on the television.  They saw the first reports about the explosion of Mount Saint Helens.  The cloud beginning to cover the sky was ash from the volcano.  It had quickly reached Ellensburg from the volcano more than three hundred kilometers away.

VOICE TWO:

The cloud had now almost covered the sky.  Scott watched the last small part of blue sky slowly disappear.  Within moments, it was as black as night.  A strong chemical smell was in the air.

Ash fell very quickly and in huge amounts.  Scott, Leslie and their parents continued to watch television reports.  Experts said they did not know what would happen.

Scott looked outside the house again.  The ash now covered the ground.  It was a frightening experience.  He wondered, “Will the ash bury us?”

(MUSIC)

VOICE ONE:

The ash that fell on Scott and Leslie Johnson in Ellensburg began flying through the air at eight thirty two in the morning, local time.  Washington State’s beautiful Mount Saint Helens had exploded.  The explosion was about three hundred fifty times more powerful than the explosions of the first nuclear bombs.

Fire, rock and volcanic gas flew out of the volcano with a force of four hundred eighty kilometers an hour.  A cloud of ash went straight up more than twenty kilometers into the air in less than fifteen minutes.  Within fifteen days, ash from the volcano traveled around the Earth in the upper atmosphere.

The explosion caused a landslide on the side of the mountain that became one of the largest such events in recorded history.  More than four hundred meters of the top of the mountain disappeared.  People near the volcano died immediately.  Thousands of animals, birds and fish also were killed.

In just a short period, thirty-five thousand hectares of forest timber was destroyed.  The heat was so fierce it killed every living thing in the immediate area, even bacteria.

VOICE TWO:

The Native American Indians in Washington State still call Mount Saint Helens by its Indian name: Loowit.  It means “Lady of Fire.”  On the morning of May eighteenth, nineteen eighty, the mountain again became a “Lady of Fire.”

The volcano had been giving warnings for three months.  These warnings were in the form of many small earthquakes. 

On March twenty-seventh, a small explosion blew away the ice and snow at the very top of the mountain.  Steam burst from the top of the volcano. 

By May seventeenth, more than ten thousand earthquakes had been measured.  These earthquakes had caused the north face of the mountain to push out more one hundred forty meters.  Volcano experts say this was strong evidence that hot liquid rock had risen high into the volcano.  It was the day before the major explosion.

VOICE ONE:

Several weeks earlier, government officials had declared an emergency.  They barred people from entering the Mount Saint Helens area.  A special permit was needed to travel near the mountain.  Officials also forced people who lived near the mountain to leave their homes.  Many were angry, and demanded permission to return. 

Some people violated government rules and visited the Mount Saint Helens area.  They did not think the volcano represented a real danger.  Workers who planted trees near the mountain were given documents that permitted them to continue their work.  Scientists also were at the mountain, studying the volcano. 

Many of these people were killed when the volcano exploded.  Fifty-seven people died as a result of the explosion.

VOICE TWO:

The volcano exploded for more than eight hours.  Then the explosions slowly began to decrease in force.  But Mount Saint Helens was not finished.  Five smaller explosions followed during the summer and autumn of nineteen eighty.  Each explosion produced ash that rose twelve to fourteen kilometers into the sky.

In the twenty-five years since then, small explosions, earthquakes and other volcanic events were reported at the mountain.  The most recent began in October of last year.  But none of the events is comparable to the May eighteenth explosion.  Still, experts say Mount Saint Helens will explode again sometime in the future.

(MUSIC)

VOICE ONE:

 
 
The United States Congress created the Mount Saint Helens Monument in nineteen eighty-two.  The monument covers a total of forty-four thousand five hundred hectares of the Mount Saint Helens area.  It includes the mountain and much of the land around it. 

The United States Forest Service supervises the area.  But nature controls it.  Trees, animals, fish, flowers and plants were left to a natural recovery process.  Humans were not permitted to help. 

The natural area around Mount Saint Helens that was almost completely destroyed is being rebuilt by nature.  Many scientists have studied what happened in this natural laboratory.  They found that nature is very quick to heal the wounds caused by the huge explosion.

VOICE TWO:

Scientists have learned much about volcanic activity since Mount Saint Helens exploded twenty-five years ago.  More than twenty smaller explosions were observed at the volcano between nineteen eighty and nineteen eighty-six.  Scientists also have been watching recent activity there.

One thing they have learned is that a volcano can come very close to exploding without giving any warning.  They also learned that volcanic activity can continue for years without any explosions taking place.

The United States Geological Survey is responsible for providing warnings of possible volcanic explosions.  It operates five volcano observation centers with the help of government agencies and universities. 

VOICE ONE:

Late last month, scientists with the Geological Survey released a report on the nation’s one hundred sixty-nine active volcanoes.  The report rates the most dangerous volcanoes in the United States.  It also discusses problems with current methods of estimating future volcanic activity.

The scientists proposed a plan to improve volcano observations and provide better information about volcanic activity.  They said the system could help prevent unnecessary and costly safety measures when such activity will not result in an explosion.  They said it also would help warn airplanes of the possibility of dangerous ash in the atmosphere.  Volcanic ash has caused millions of dollars in damage to planes and other aircraft in the past.

(MUSIC)

Earlier, we told how Scott Johnson was concerned twenty-five years ago that the ash from Mount Saint Helens might cover his home.  That did not happen, although the ash was deep in some parts of town.  It had to be removed from streets and from tops of houses.  Travel was almost impossible for several days.

Today, Scott Johnson is an engineer in Seattle, Washington.  Leslie Johnson is a medical doctor in Portland, Oregon.  Both say the Mount Saint Helens explosion was an experience they never will forget.

(MUSIC)

VOICE ONE:

This program was written by Paul Thompson and Nancy Steinbach.  Cynthia Kirk was our producer.  I’m Barbara Klein.

VOICE ONE:

And I’m Doug Johnson.  Join us again next week for another SCIENCE IN THE NEWS, in VOA Special English.  

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