Protecting Resources on the Farm
Time Duration
45-60 minutes
Purpose
Students will learn how soil cover and plants can reduce soil erosion. They will also see these practices put to use by farmers.
Kentucky Academic Standards
NGSS
4-ESS2-1 Make observations and/or measurements to provide evidence of the effects of weathering or the rate of erosion by water, ice, wind, or vegetation.
5-ESS3-1. Obtain and combine information about ways individual communities use science ideas to protect the Earth’s resources and environment.
Materials
“Protecting Resources on the Farm” digital presentation - includes a demo of the activity
Large pan (9” x 13“) with bare soil
Large pan with sod or soil with growing plants - You may be able to use the ryegrass from Activity 3 or dig up a layer of sod from the side of a schoolyard. Replace the sod when you are done.
Pitcher or bottle of water
Jar or bowl to collect the water “run-off”
Prepare
Show students the “Protecting Resources on the Farm” digital presentation. Explain the term “conservation” (the controlled use and systematic protection of natural resources such as forests, soil, and water). Inform students that farmers must be conservationists and find ways to care for the soil and water on their farms to produce the best crops, provide clean water for their livestock, and ensure that groundwater remains clean.
Two problems farmers face are erosion and run-off:
Erosion: Explain to students that erosion is the wearing away of the land by wind, water, or ice (though this is not an issue in Kentucky). See photos in the digital presentation.
Run-off: Explain to students that the water that washes away soil and other materials during heavy rain is called run-off. Without a filter, the soil and materials enter waterways (creeks, streams, and rivers).
Farmers can protect their soil by sowing “cover crops,” which are non-food crops that prevent erosion, boost soil nutrients, provide habitat for beneficial organisms, and filter water. In addition, the cover crops decompose and provide nutrients for the next crop. Farmers also improve the soil by adding organic matter and tilling it less than they did before. No-Till, the practice of leaving the organic matter from the previous crop on top of the soil and not breaking the soil layer with machinery was started by Kentucky farmers. No-till reduces soil erosion and increases the amount of water the soil can hold.
Farmers also sow plants around the edges of crop fields and waterways. These “buffer strips” or “filter strips” provide a barrier between the field and waterways. The plants will filter soil and materials from the water before it enters waterways. Farmers also keep a watchful eye on the weather. For example, they will not apply nutrients to fields if they know it will rain in the next day or two.
When farmers have livestock, they can keep animals and their waste off bare soil or near streams.
Procedures
Place some local soil in a large container, such as a 9”x13” pan. Tilt pan and have a student gently sprinkle water, starting at the top of the soil. Watch what happens as the water carries bits of soil along with it. Discuss what effects erosion has on plants, why farmland is usually flat land, and how to prevent erosion (by planting).
Collect a piece of sod (top layer of soil with grass) and place it in a similar container. You may also plant grass seeds in a container and repeat the process to demonstrate how plants help prevent erosion. After the grass has started growing and has produced roots, the amount of soil washing away (eroding) should be visibly reduced.
Try the experiment again with contaminated water (add dirt, dead leaves, sand, etc.) and pour it over each pan. Did the pan with the cover crop filter the “contaminants” out of the water?
Discuss the importance of keeping soil covered. Students may also read about other ways our Kentucky farmers protect their ecosystems and the environment. Articles and comprehension questions are available here.
View an alternate version of this demonstration (using plastic bottles - included in the digital presentation): https://youtu.be/im4HVXMGI68
