環(huán)球英語—847：A Plant for All Seasons

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Welcome to Spotlight. I’m Colin Lowther.
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And I’m Robin Basselin. Spotlight uses a special English method of broadcasting. It is easier for people to understand, no matter where in the world they live
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Mr. Banani is a farmer in the African country Mali. Mr. Banani shared his story with reporter Lydia Polgreen. One day, his brothers encouraged him to try a new crop. He had trees around his farm, to protect his food crops from the wind. The trees dropped poisonous black seeds. But they did not seem to have any other use. But Mr. Banani’s brothers wanted him to plant these trees in his field! They said that these seeds could make oil to power a generator, or vehicle. And they also said that with these seeds, Mr. Banani could make a lot of money!
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So what was this amazing plant? Are farmers like Mr. Banani successful? Today’s Spotlight is on the promise and problems of the Jatropha plant.
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The ground is dry. It is covered with sand and rocks. The wind blows the sand around. There is no sign of water. But under the ground there is water, in small amounts. And this is enough for Jatropha. When it is too dry, Jatropha is dormant - it sleeps. When there is any water at all, it will start to grow again.
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Jatropha is a small tree, about three to five metres tall. However, when conditions are good it can grow as high as ten metres! Its large green leaves fall off in the winter. It produces white flowers and fruits several times each year. And when people crush the seeds, oil comes out. This oil is very useful.
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For the last several years, scientists have been using Jatropha seeds to make biofuel. Fuel is something that everyone uses. The most common fuel in the world is oil. Oil powers most of our modern life. As gasoline, it powers cars, trucks and airplanes. It also powers machinery. People use it to create electricity too.
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But traditional oil has many problems. It is taken from the earth, through mining. Once it is used, it is gone - there is a limited amount. It is only found in some places. And it can be dangerous. Miners can be hurt or killed. And it causes serious pollution.
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Some people have suggested that biofuel could be the answer to this problem. Biofuel is oil that comes from other resources - like the Jatropha plant. The seeds from one hectare of Jatropha can produce as much as six hundred litres of oil. This is when conditions are good, with enough water and sun light. Even when conditions are less good, the same area of Jatropha can produce about two hundred litres of oil.
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Oil grown this way is renewable. That is, it can never be used up completely. People can always grow more Jatropha seeds. And it is not dangerous to grow, or harvest the oil. Scientists combine this plant oil with traditional oil from the ground. This is biofuel.
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People are already using Jatropha oil in the Philippines. In India, it helps to power a train that runs from Mumbai to Delhi. There, Jatropha plants grow by the railway line. In New Zealand one airline has tested the use of Jatropha oil. The plant grows well in South America and the oil from the seeds is used in South America’s largest country, Brazil. Oil from Jatropha is also used in Mali in Africa, and there are plans to use it in Namibia as well.
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Jatropha can grow in many places, even in poor soil. It can live for over fifty years. It can survive long periods without rain. And, instead of taking food out of the soil, it feeds the soil. People in India say that the plant is easy to grow. By putting its roots down in sand, it prevents the land from becoming a desert. For the same reason it helps to prevent the rain from washing away good soil. In some places, farmers use it between fields, to protect their crops from high wind.
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You may think that Jatropha is the perfect plant. It is easy to grow. It provides fuel, and food for the soil. It can grow in many kinds of soil, and it can survive when there is no rain. So why is development so slow? And why did one of the world’s major oil companies stop supporting a project which involved Jatropha?
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One reason may be that the plant contains poison. People can cook and eat Jatropha seeds. But eating even three uncooked seeds can kill a person. So Jatropha cannot be used as a food crop. In Western Australia, the authorities banned one kind of Jatropha in 2005 because it contained poison. But the Australians had another reason too. They said that the plant was invasive. That is, it takes land away from native plants. It spreads quickly, and it can kill other plants.
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There is another problem. Farmers in many places hope that Jatropha will be a way to make more money. European countries are trying to increase the use of biofuels like Jatropha. Because of this important market, governments in developing countries have encouraged farmers to grow Jatropha.
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Jatropha does grow well in dry conditions. But Jatropha produces the most oil when it can drink a lot of water. And people have mainly encouraged it in places without much water. So it has not produced as much oil as scientists promised. This has lead major oil companies to stop their support of Jatropha. In places where it is grown, Jatropha crops have taken water and land away from food crops. Farmers grow Jatropha, instead of much needed food crops.
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The last word today comes from the people of Kenya. There, the government is encouraging farmers to grow Jatropha. But people are afraid that Jatropha will stop good native plants from growing. They are also worried about how much water it will need to grow well. The country is moving forward with Jatropha plants. But will it help or hurt the farmers?
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What do you think? Should farmers and companies invest in Jatropha? Or should they be concentrating on other kinds of plants?