- About Us
- Teacher Center
- Student Center
Students will understand that topsoil is a limited resource with economic value. Activities include slicing up an apple to demonstrate the distribution of Earth’s soil resources and exploring scenarios involving the dollar valuation of soil.
conservation tillage: farming methods that reduce the intensity or frequency of tilling in order to maintain some ground cover throughout the year and disturb the soil as little as possible while still providing the conditions needed to grow a productive crop
contour planting: tilling and planting crops on the contour, or at a right angle to the slope, which slows water flowing downhill and reduces erosion
cover crops: crops grown between periods of regular production for the purpose of protecting and improving the soil; generally a crop with fibrous roots (like clover, various grasses, vetch, etc.) that will hold soil and often a legume that will add nitrogen to the soil
nonrenewable resource: a limited natural resource that cannot be replaced or reproduced at a rate that will meet demand over the long term
strip cropping: planting in strips or bands of alternating crops that serve as barriers to erosion; crops that have fibrous roots hold the soil better than crops with tap roots, and taller crops act as wind buffers
sustainable agriculture: an approach to agriculture that focuses on producing food while improving the economic viability of farms, protecting natural resources, and enhancing quality of life for farmers and society as a whole
value: usefulness or importance of something; also, the amount of money that something is worth
Agriculture is an important part of the economy of the United States. In 2013, more than 16 million people had farm- and agriculture-related jobs. Agricultural exports are translated into billions of dollars for United States trade. On poor soil, it costs farmers more to produce good crops, and this cost is passed on to the consumer—you—in higher prices at the grocery store. Erosion reduces agricultural productivity and washes sediment into rivers, lakes, ocean gulfs and bays, affecting fisheries and recreation opportunities in these water bodies. Soil loss affects our country’s economy and our lives.
The United States has more high-quality agricultural land than any other country in the world. Just over half of our land is used for agricultural production, and that production depends on good soil. It can take 100 to 500 years to make one inch of topsoil. From the perspective of a human lifetime, soil is a nonrenewable resource. Fertile topsoil produces the highest yields of food per acre, and farmers will work hard to protect their soil, but erosion can be complicated and expensive to address.
In the United States, cropland erosion decreased by more than 40% between 1982 and 2007. During this time, more and more farmers implemented practices like strip cropping, contour planting, conservation tillage, and planting cover crops to help mitigate wind and water erosion. Erosion has slowed over the past 30 years, but we are still losing millions of tons of topsoil each year at a rate much faster than the natural replenishment rate. Farmers don’t always have the resources needed to implement soil conservation practices. For example, cover crops effectively reduce erosion, but the seed for the crop costs money, takes time to plant, and needs water to grow, and the cover crop doesn’t directly generate any income for the farmer.
Soils produce our food, keeping us alive. How do we put a value on soil or land? Many would say it is simply invaluable, but farmers have to make economic decisions about the soil every day. They cannot spend more to protect the soil than they earn from selling their crops, or they will go out of business. Yet, if farmers don’t protect the soil, many years of erosion could destroy the productivity of our valuable agricultural soils. The field of sustainable agriculture has grown out of problems like this. Agricultural scientists, policy makers, engineers, and many others are working to help farmers develop techniques that are economically viable, produce the food we need, and protect natural resources like soil and water over the long term.
Activity 1: Slicing Up Earth’s Land Resources
Activity 2: Cost versus Value
Concept Elaboration and Evaluation
After conducting these activities, review and summarize the following key concepts:
We welcome your feedback! Please take a minute to tell us how to make this lesson better or to give us a few gold stars!
If you are unable to acquire an apple, you can view The Earth as an Apple video instead.
Connect this lesson to Utah Studies by showing students the 14-minute video Dust Bowl: Grantsville Utah. This short documentary includes interviews from Utah residents who experienced the Grantsville Dust Bowl in the 1930s. Yes, Utah did experience its own dust bowl, but the cause was overgrazing rather than the turn of the plow.
Read Issue 3 of Ag Today titled Our Invaluable Natural Resources. This reader can be printed or accessed digitally. It helps students understand how plants and animals raised on farms depend on natural resources to live such as the sun, soil, water, and air to grow. Learn methods farmers use to protect and preserve these natural resources while still providing the food, fiber, and fuel we need to live.
Adapted from materials provided by Oklahoma Agriculture in the Classroom.
Utah Agriculture in the Classroom