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Food for Crops: How to Get the Most From Organic Fertilizer
Written by Mario Ritter

I’m Shep O'Neal with the VOA Special English Agriculture Report.

 
 
There are many different products that farmers can use to add nutrients to soil.  Organic fertilizers usually come from animal waste, plant material or treated wastewater. 

Farmers who raise animals have a ready-made fertilizer to mix into the soil.  However, animal waste must be treated in order to make good fertilizer. 

Composting is a natural method.  It uses the action of bacteria and other organisms to break down the manure into fertilizer.  The manure must be mixed with a material that provides carbon, such as wood cuttings.  The carbon supports the growth of the organisms.

It is important to mix in enough carbon-supplying material.  If there is too little, nitrogen in the waste will release ammonia gas and smell terrible.

Composting also requires the right amount of water and air.  The compost material should be loose and easy to turn with hand tools.  The compost should be about fifty to sixty percent water.  Too much water will mean that air cannot reach all the material.  This will cool the compost.  It will slow the organic activity and cause a bad smell.  Too little water will also stop the activity.

The process of composting produces heat.  If conditions are good, the compost material should reach about fifty to sixty degrees Celsius.  This heat kills dangerous organisms in the animal waste.  Experts say all of them will be killed if the material stays at fifty-five degrees for fourteen days. 

It takes three to seven months for compost to become ready to use as fertilizer.  After this time, the material will have lost twenty to sixty percent of its mass.

Waste products provide one fertilizer resource.  Some crops supply limited amounts of nutrients to the soil.  Beans release nitrogen.  Crops like alfalfa can be left to break down. 

There are many different kinds of manufactured fertilizers.  The most commonly used mineral fertilizers are nitrogen-based.  Nitrogen from the air is mixed with hydrogen from natural gas.  This process produces ammonia gas.  Other elements are then added to the ammonia. 

Different crops demand different mixtures of nutrients. Many farmers invest in special fertilizers designed just for the kinds of crops they grow. 

This VOA Special English Agriculture Report was written by Mario Ritter.  Our reports are online at voaspecialenglish.com.  We will also have links to more information about composting.  I'm Shep O'Neal.

High Hopes Travel with Newest Flight to Explore Mars
Written by Jerilyn Watson, Caty Weaver and Cynthia Kirk

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VOICE ONE:

This is SCIENCE IN THE NEWS in VOA Special English.  I’m Bob Doughty.

VOICE TWO:

And I’m Barbara Klein.  On our program this week, we will tell about the man who first confirmed a link between smoking and lung cancer.  We also will talk about a large study of vaccines – those medicines used to protect against disease. 

VOICE ONE:

But first, we report on a flight to the planet Mars.

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VOICE ONE:

 
Mars Reconnaissance Orbiter 
An American spacecraft is traveling to Mars to collect information about the red planet.  The Mars Reconnaissance Orbiter left Cape Canaveral in Florida on August twelfth.  An Atlas V launch rocket sent the orbiter on its trip to Mars.  The space vehicle is expected to arrive in March of next year.  It is to orbit the planet for at least four years. 

The orbiter was designed to tell scientists about the weather, climate and surface of Mars.  The American space agency hopes to get as much information from it as from all earlier trips to Mars combined. 

VOICE TWO:

Space agency scientists praised the launch.  The huge rocket that lifted the orbiter from Earth dropped into the Atlantic Ocean after about four minutes.  Less than an hour after the launch, the orbiter separated from the upper rocket, as planned.  Then the vehicle quickly established radio communication with its controllers.

The launch came two days after the space shuttle Discovery returned safely to Earth.  Space agency officials had planned to launch the orbiter on August tenth.  But technical problems caused delays. 

VOICE ONE:

The orbiter’s operations are costing more than seven million dollars.  The space vehicle will do two main kinds of work.  Each will last about two years.  Its first job is to study ice on Mars.  Scientists say they believe that long ago, the planet was warm and wet.  As such, Mars might have supported living things.  Now it is dry and cold.  There are large areas of frozen water at the opposite ends of Mars.  Scientists hope to learn if people could survive conditions there.

Instruments on the orbiter are to examine the atmosphere, surface and below-surface areas of the planet.  Two cameras will show images and provide maps of Martian weather.  A device called a spectrometer will identify minerals on the ground.  Another device, a radiometer, is to measure dust in the atmosphere.  Radar that can show areas under the surface of ice and rocks also will be used.  The Italian Space Agency supplied the radar.

VOICE TWO:

The orbiter’s second job is to communicate messages between Earth and mechanical devices on Mars.  The American space agency has two robotic explorers operating on the planet.  The robots Spirit and Opportunity were launched in two thousand three.  They can send information to Earth and also receive messages.  They do this with the help of satellites placed in orbit around the planet. 

Information from the Mars Reconnaissance Orbiter is expected to help the space agency decide where to land two more robot-explorers.  A device called the Phoenix Mars Scout will search for organic chemicals.  It will be launched in two thousand seven.  The Mars Science Laboratory is to be launched two years later. 

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VOICE ONE:

Researchers in Denmark say a large study of Danish children shows that vaccines do not weaken a child’s natural defense system against disease.  Doctor Anders Hviid of the Statens Serum Institute in Copenhagen led the study. 

The scientists examined medical histories of more than eight hundred thousand children.  The boys and girls were born in Denmark between nineteen ninety and two thousand one.  They all took part in a national vaccination program to prevent common childhood diseases.  The program provides children with protective medicines every few months for their first eighteen months of life.  Then they receive additional vaccines each year until they are five.

VOICE TWO:

Some health experts had questioned whether the large number of vaccinations could damage the body’s natural defense system.  There was special concern about combination vaccinations, like the measles-mumps-rubella vaccine.  These are three vaccines mixed together in one injection.

Some people have been concerned that the vaccinations might make the immune system work too hard and weaken it.  They thought this could leave a child more at risk for diseases not targeted by the vaccines.

VOICE ONE:

The Danish researchers looked at the children’s rates of hospital admissions for treatment of infectious diseases not targeted by the vaccines.  Such diseases included diarrhea and the lung infection, pneumonia. 

The researchers say they found no increased risk for hospitalizations in the weeks following vaccinations. They found that none of the six kinds of vaccines the children received increased the risk for seven other major infectious diseases.

Some children’s health experts say the study provides more evidence that vaccines are safe.  They say the results should make parents feel sure about getting their children vaccinated. The study was published in the Journal of the American Medical Association.

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VOICE TWO:

 
 
For years, scientists have warned that smoking tobacco is bad for your health.  Many studies have linked smoking to lung cancer.  One of the British scientists who first confirmed the link died last month.  Richard Doll was ninety-two years old.  Officials at Oxford University say he died after a brief sickness. 

Professor Doll has been praised as one of the most important medical scientists of the twentieth century.  His work has been recognized around the world.  His studies into the health effects of smoking are said to have saved the lives of millions of people. 

The United Nations World Health Organization estimates that one thousand three hundred million people worldwide use tobacco products.  Officials estimate that tobacco use is responsible for about five million deaths a year. 

VOICE ONE:

William Richard Shaboe Doll was born in nineteen twelve in Hampton, England.  He began studying medicine after failing a mathematics test.  He studied at Saint Thomas’s Hospital Medical School in London.

Richard Doll served in the Royal Army Medical Corps during World War Two.  After the war, he started work at Britain’s Medical Research Council.  While there, he was asked to investigate why a growing number of people had developed lung cancer. 

At first, Professor Doll thought that gasses released from automobiles was the cause.  He and other research scientists questioned hundreds of lung cancer patients to find a common link.  They found that the only thing the patients had in common was smoking. 

VOICE TWO:

Professor Doll worked with Austin Bradford Hill of the Medical Research Council.  They showed that smoking is a major cause of lung cancer.  They also showed the risk of developing lung cancer was directly linked to the number of cigarettes smoked. 

Their findings were announced in nineteen fifty-one and confirmed in a study published three years later.  In nineteen fifty-seven, the Medical Research Council officially accepted the direct causal connection between smoking and lung cancer. 

VOICE ONE:

Professor Doll said he himself stopped smoking because of the findings.  He would later produce more evidence of the direct link. 

He also showed that smoking could cause many other kinds of cancer and diseases.  He investigated evidence linking alcoholic drinking with breast cancer.  He studied the harmful effects of radiation.  He also wrote papers on electric power lines and peptic ulcers. 

Professor Doll was named the top professor of medicine at Oxford University in nineteen sixty-nine.  Ten years later, he helped to create Green College, a college for the study of medicine.

VOICE TWO:

Professor Doll received many awards throughout his life.  The World Health Organization honored him for his work.  In nineteen seventy-one, Queen Elizabeth made him a knight, one of Britain’s highest honors. 

Last year, Sir Richard Doll released a follow up study to the one published more than half a century earlier.  The study showed that as many as two thirds of people who begin smoking when they are young will later die as a result of the activity.

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VOICE ONE:

This SCIENCE IN THE NEWS program was written by Cynthia Kirk, Jerilyn Watson and Caty Weaver.  Cynthia Kirk was our producer.  I’m Bob Doughty.

VOICE TWO:

And I’m Barbara Klein.  Join us again next week at this time for more news about science in VOA Special English.  

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