Scientists are trying to make the deserts into good land
again. They want to bring water to the deserts so people can live and grow good.
They are learning a lot about the deserts. Even so, more and more of the earth
is becoming desert all the time. Scientists may not be able to change the
deserts in time. Why is more and more land becoming desert
Scientists think that people make deserts. People are doing bad things to the
earth. Some places on the earth do not get very much rain. Yet
they still do not become deserts. This is because there are some green plants
growing there. Small green plants and grass are very important to dry places.
Plants help keep water in the earth. Plants do not let the wind blow the dirt
away. Without plants, the land can become a desert much more easily.
A man decides to make a farm in a very dry place. He cuts down the trees.
He digs in the earth and takes away the grass and plants that are already
growing on the dry land. He makes a farm. He puts plants in rows. The sun is
very hot. It makes the land even drier. When the rain comes, it runs between the
rows of plants. It washes the good dirt away. When the wind comes, it blows
between the rows of plants. It blows the good dirt away. Soon
the land is not good enough for a farm anymore. The man lets his animals eat all
the plants on it. Now the land does not have any plants on it. The sun and wind
dry the land and blow all of the good dirt away. Now the land is a desert. What is mainly discussed in the passage