Desertification
When healthy farmland becomes dry desert it is called desertification. Trees and plants act like an anchor for the soil. When they are cut down, the fertile topsoil is blown or washed away. The soil that remains cannot hold water, so plants cannot grow, and the land becomes desert. Humans are responsible for 80-90% of the 27 million hectares a year that become useless for farming due to desertification. Desertification is caused by logging, poor irrigation techniques, road construction, mining, polluting and animal over-grazing. These harmful activities are on the increase because the Earth’s population is growing. As a result, the Earth has more people to feed, but there is less and less land available on which to grow food.