Soil erosion is the movement and transportation of soil by various natural processes. Erosion is responsible for the loss of an average of 12 tons per acre of agricultural soils per year. The soil that is most affected by erosion is the topsoil layer. Soil erosion is accelerated by a sloped landscape, removal of vegetation for landscaping, soil tillage for agriculture and drought. Wind and water play a monumental role in soil erosion.
On agricultural land, erosion causes loss of nutrient rich topsoil, which results in an increased need for fertilizer being added back to soils. This can lead to further problems as fertilizer runoff leads to water contamination, which affects the habitats of area livestock and wildlife.
Water erosion is the focus of our lab today. Erosion from water removes topsoil from agricultural land and can cause runoff of nutrients to nearby water supplies, jeopardizing surrounding wildlife habitats.
Soil is an important part of the Kansas economy. Nearly 50 percent of the state is covered in crops, while 34 percent is covered in range and pasture lands, according to the Natural Resources Conservation Service. This land provides nearly $8.7 billion in annual income through our number one industry, agriculture.
Although Kansas is blessed with abundant soil, each year, 190 million tons of Kansas topsoil is degraded through human activities. It took hundreds of years to create the Harney silt loam soil in Kansas, and it’s not easily renewed.
To help preserve the soil, farmers use sustainable techniques, such as cover cropping and no-till. Each of these allow soil to build nutrients and improve soil structure. No-till crop ground allows soil nutrients to stay below the surface, reduces the erosion of soil nutrients and is often used in conjunction with cover cropping. The use of cover crops helps reduce water runoff that not only carries water away from the plants, but often takes nutrients needed for crop growth along with it. In this lab, we are going to test the protective capabilities of a cover crop against soil erosion from water.
Watch these two videos to get a better idea of what these two farming techniques are and why we need to utilize them.
In order to gain a better understanding of soil runoff and the role of cover crops and no-till farming you will be constructing a set up for demonstrating this process. During this experiment you will see first-hand what farmers are doing to prevent the loss of nutrient rich topsoil.
Lab Setup Length of Time for Preparation: 30-40 minutes.
Note: See the extended Learning section below for other options.
Perform the Lab
Extended Learning
There is an option to add two additional bottles to this lab to show how vegetation can help with soil erosion. This would involve growing wheat or grass in the 3rd and 4th bottles, and in the 4th bottle, you would add wheat stubble (prior year cover crop). Adding two additional bottles would allow the students to compare:
Note: This would add about 2 weeks to the lab prep in order to grow the wheat seed in the two bottles. The restof the procedures remain the same for the lab.
You can also take the collection cups and measure the mass of the amount of soil and sediment that drained out of the bottles. One way to do this would be to filter the runoff water through a paper towel. This would make this a multiple day lab which you might need to move your set up to an alternate location which does not impede the normal function of your sink. You can then graph the amount of soil that eroded away each day.
• Agricultural inspector • Agricultural specialist • Soil and plant scientist • Crop production specialist
To learn more about agriculture careers, visit agexplorer.com. You can also find career profiles at kansascornstem.com.
This lesson is the work product of the Kansas Corn Commission. Our lessons are written in collaboration with Kansas teachers for use in the classroom. Teachers may copy and share this curriculum. Use of this product for commercial or promotional use is prohibited without express permission of Kansas Corn.
As the need to produce more food with less resources grows, it is important that future generations have a better understanding of agriculture and how corn farming and agriculture fit into our daily lives. That’s why the Kansas Corn STEM program provides lessons to teach science through the lens of corn. We are committed to providing free materials and training to support educators.
