第24回 の解答

Farming Without Soil

Farming has traditionally depended on good soil, enough water, and suitable weather. However, farmers today face many challenges. Climate change has brought more droughts and floods, which can destroy crops. In addition, in countries such as Japan, the number of farmers is declining as many of them grow older and young people move to cities. As a result, people have become interested in new ways of producing food.

One of these methods is hydroponics, a way of growing plants without soil. Instead, the roots of the plants are placed in water that contains all the nutrients they need. Many hydroponic farms are built indoors, where temperature and light are controlled by computers, and some are "vertical farms" in which plants are grown on shelves stacked many levels high. Because the water is reused, these farms use up to ninety percent less water than traditional farms, and crops can be harvested all year round.

However, indoor farming also has problems. The LED lights and air conditioning use a lot of electricity, so costs can be high. For this reason, most vertical farms grow vegetables such as lettuce, which grow quickly and sell at good prices, while crops like rice and wheat are still too expensive to produce this way. Several vertical farming companies have gone out of business in recent years because of rising energy prices.