Soil Conservation

Vocabulary Word conservation (kahn sur VAY shuhn) careful use of resources to reduce damage to the environment Soil conservation involves reducing the amount of _. resources available damage to soil soil on farms Reading Comprehension You might think that Earth has plenty of soil. But not all soil can support the growth of plants. Land suitable for farming is called arable soil.Nearly 75% of Earth's surface is covered in water, so only 25% of the surface is dry land. Much of the remaining land is too high, too cold, or too hot to farm. The land may be too steep, too rocky, too dry, or lacking in nutrients to grow crops. That leaves only about 10% of Earth's surface as arable land! _ of Earth's surface can support plants. All Ten percent Seventy-five percent Since 1960, nearly one-third of the arable land on Earth has been lost to overuse, erosion, and other human activities. At the same time, Earth's population has increased. That means there is even less land available for each person. Humans must conserve the remaining useful soils. Conservation is the careful use of resources to reduce damage to the environment. Over time, the amount of arable land on Earth has _. increased decreased stayed the same Farming and construction speed up erosion. Both break up the soil. This makes it easier for wind or water to carry the soil away. One way to conserve soil is to build fences around construction sites. This can keep the soil from blowing away. Breaking up the soil _ down erosion. slows down speeds up does not effect Windbreaks are rows of trees planted around the edges of farm fields. Trees slow the wind and reduce wind erosion. The tree roots absorb water that might otherwise run across and erode the soil.The steeper the slope of a field, the greater the soil loss when water runs down the hill. Planting crops in rows that run up and down the hill encourages more runoff. This means that more soil is carried away. In contour farming, farmers plant crops along the natural curves, or contours, of the land. Rows of plants that run at right angles to the water's flow reduce the amount of soil that is lost. Planting crops along the natural curves of the land _. increases erosion by wind increases erosion by water reduces erosion by water Some crops, such as corn, stick up out of the ground. Runoff flows along the bare ground between the rows. Other crops, such as alfalfa, cover the ground so there are no natural paths for the runoff. Strip cropping is the practice of planting alternating strips of cover and row crops. Farmers plant these strips along the natural curve of the land to reduce water erosion. Planting the strips at right angles to the normal winds also reduces wind erosion. In the past, plowing, planting, fertilizing, and weed control were all done in separate steps. But the less the soil is disturbed, the less chance there is for erosion. In no-till farming, the crops are planted without tilling, or plowing up, the previous year's crop. Once crops are planted, the ground isn't disturbed again until the plants are harvested. As the new crop grows, the roots from the older plants hold the soil in place and provide nutrients to the soil. Strip cropping can _. reduce erosion completely stop erosion increase erosion Word Usage One good way to learn words is to use them. Replacecommon words with more precise terms. Use science terms when you need a specific idea.Choose the best word from the set and type it in the blank. *HINT: The words are used in the passage!*The first one has been done for you. 1. Land suitablefor farming is called arable soil. (suitable, terrible)2. Many items of junk food contain few nutrients. (calories, nutrients)3. There isn't much arable land in our backyard for a garden. (arable, clear)4. Be careful to conserve your energy during the race. (use, conserve)5. We're planning the construction of several birdhouses for our backyard. (demolition, construction)6. That towel is too thin to absorb much water. (absorb, dry)7. They build the road to follow along the curve of the hill. (slope, curve)8. The runoff from the last storm washed away my grass seed. (runoff, water)9. Soil conservation involves reducing damage to the environment. (reducing, increasing) Graph Which year had the most amount of farmland per person? 1961 1970 1980 1990 Which year had the least amount of farmland per person? 1961 1980 1990 2002 What has happened to the amount of farmland per person since 1961? It has stayed the same. It has doubled. It has decreased. It has increased.