In South America, the rich soil of the Amazon River basin in Brazil is known as "black gold". Scientists found that the secret of this rich soil was charcoal . Local people made it from animal bones and tree branches. They mixed the charcoal with the soil about 1.500 years ago. 

Now, scientists in the United States have done a modern demonstration. They say charcoal fertilization offers a revolutionary way to improve soil quality for hundreds or even thousands of years. 

Mingxin Guo and his team at Delavare State University heated tree leaves, corn stalks , small pieces of wood and poultry waste into "biochar" . They reported their findings at a recent meeting of the American Chemical Society in New Orleans. 

Biochar could be good news for farmers with poor soil and hungry populations to feed. Professor Guo says it could even help against global warming. Intensive farming and overuse of chemical fertilizer give out carbon dioxide into the atmosphere. Biochar does the opposite, he says. It traps carbon in the ground. 

The researchers planted winter wheat in containers of soil in a greenhouse -- some with biochar, some without. Professor Guo says the wheat grows much better in the pots with biochar. The soil was added two percent charcoal to. But he says even a one percent treatment will increase productivity. 

The results demonstrated that biochar can increase organic matter in soil. Loss of nutrients in soil is an increasing problem worldwide as farmers try to grow more food for growing populations. 

Next, the team will carry out a five-year study of biochar with spinach , green peppers and tomatoes. 

Mingxin Guo says he learns about the "black gold" in Brazil from a magazine story. He explains that it was discovered in the jungle, in the area where waters flow to the Amazon, in the 1960's. But it was not until recent years that scientists began to bring public attention to it. QUESTIONS:

Q1:
1. What country is home to the Amazon River basin?
2. In what nation can the Amazon River basin be found?
3. What is the location of the Amazon River basin?
Q2:
1. What is the soil like in the Amazon River basin?
2. What kind of soil is found in the Amazon River basin?
3. What is unique about the Amazon River basin's soil?
Q3:
1. What is another name for the Amazon River basin's rich soil?
2. What else is the Amazon River basin's soil called?
3. How is the Amazon River basin's rich soil often referred to?
Q4:
1. Who rendered the Amazon River basin's soil so rich?
2. Why is the Amazon River basin's soil like black gold?
3. Who made the Amazon River basin's soil the way it is today?
Q5:
1. How did local people enrich the Amazon River basin's soil?
2. What did local people do to make the Amazon River basin's soil so rich?
3. How was the Amazon River basin's soil fortified by local people?
Q6:
1. When did local tribes enrich the Amazon River basin's soil?
2. At what point in history was the Amazon River basin's soil fortified by local people?
3. When in history did local populations render the Amazon River basin's soil rich?
Q7:
1. What country is replicating the richness of the Amazon River basin's soil in the present day?
2. What country is doing modern demonstrations of the local Amazonian people's enriching of the Amazon River basin soil?
3. Which nation is duplicating the methods of local Amazonians who had enriched the soil of the Amazon River basin?
Q8:
1. Which scientist is heading the United States soil project?
2. Who is the scientist in charge of the US intiative to enrich soil?
3. What is the name of the researcher leading the US project on soil enrichment?
Q9:
1. Does Mingxin Guo work alone?
2. Is Mingxin Guo researching on his own?
3. Does Mingxin Guo work without a team?
Q10:
1. What school does Mingxin Guo work for?
2. What university employs Mingxin Guo?
3. Which university is Mingxin Guo's place of employment?
Q11:
1. How did Mingxin Guo learn about black gold?
2. What did Mingxin Guo learn regarding black gold?
3. What brought the notion of black gold to Mingxin Guo?
Q12:
1. What was the location of black gold's discovery?
2. Where was black gold first come across?
3. In what location was black gold seen for the first time?
Q13:
1. When was black gold found?
2. At what point was black gold discovered?
3. When did the discovery of black gold occur?
