Soil erosion is the movement and transport of soil by natural processes like wind and water that can remove 30 tons of topsoil per hectare annually. This topsoil loss is accelerated by activities like agriculture and drought. In Kansas specifically, 190 million tons of topsoil are degraded each year. To help prevent erosion, farmers use sustainable techniques like cover cropping and no-till farming to build soil nutrients and structure. A classroom lab demonstrates how cover crops can significantly reduce water erosion by setting up two bottles with soil - one with a cover crop layer and one without.
1. The Importance of Soil!
What effect does soil erosion have on farming?
2. What is a Soil erosion?
โข https://www.youtube.com/watch?v=ofhQvAu_L1I
3. Effects of Soil Erosion
โข Soil erosion is the movement and transport of soil by various
natural processes and is responsible for the loss of an average of
30 tons per hectare 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, the removal of vegetation to
create land space, soil tillage for agriculture, and drought. Wind
and water play a monumental role in soil erosion.
4. Effects of Soil Erosion
โข 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 itโs not easily
renewed.
โข To help preserve the soil, farmers use sustainable techniques like cover
cropping and no-till. Each of these allows soil to build nutrients and
improve soil structure. No-till crop ground allows soil nutrients to stay
below the surface and reduces the erosion of soil nutrients and can often
be used in conjunction with cover cropping. The use of cover crops helps
reduce water runoff that not only carries away water away from the plants,
it often takes nutrients that help crops grow along with it.
โข 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
5. What can be done?
โข To help preserve the soil, farmers use sustainable techniques
such as cover cropping and no-till. Each of these allows soil to
build nutrients and improve soil structure.
โข No-till crop ground allows soil nutrients to stay below the
surface and reduces the erosion of soil nutrients and is often
used in conjunction with cover cropping.
โข The use of cover crops helps reduce water runoff that not only
carries water away from the plants, but it often takes nutrients
needed for crop growth along with it.
6. No till agriculture!
โข https://www.youtube.com/watch?v=lLgasUNJfXs
โข I like this one but it is from IOWA Great no till video
7. Cover Crops in Kansas
Click on the picture and watch
the video on Cover Crops in
Kansas. Stop at the 2:46 mark.
8. The lab!
โข Bottle Setup:
โข Cut out an area approximately 3โ x 10โ along the side of 2
bottles. Label to bottles 1 and 2
โข Fill each bottle with 3 cups of garden soil.
โข Add a layer of wheat stubble to the top of bottle 2.
โข OPTIONAL: You can use a three bottle method and plant some
wheat in bottle number 2 before putting on the wheat stubble.
This will add approximately 1-2 weeks for the germination of the
wheat.
10. Procedure Continued!
โข Position the bottles so there is enough overhang so you can get a 1,000-mL
beaker underneath them. (I use the sink and the neck of the bottle drains into the
beaker sitting in the sink.)
โข The bottles need to be angled slightly with the neck of the bottle pointing
downward. (You can use a textbook under the end to elevate the bottle), (I used a
3-ring binder 1โ to 1/2โ to sit my bottles on so they were angled downward.)
โข Starting in the back end of the bottle (farthest away from the neck). pour 700 -
800 mL of water into bottle 1.
โข Let the water drain out the neck into the โcollection bucketsโ.
โข Repeat for bottle 2.
โข (Optional). Repeat for bottle 3, if you grew your wheat from the seeds.
โข (Optional). You can repeat the above steps for multiple days if you choose to see
how much erosion would take place over a certain time period.
11. Post Lab Questions!
โขWhich bottle had the most erosion
present?
โขWhich bottle had the least amount of
erosion present?
โขWhy are cover crops important to
farmers?
12. Take it Further
You can have your students take the
collection cups and measure the mass
of the amount of soil and sediment that
drained out of the bottles. If you do this
as a multiple day lab, they can graph
the amount of soil that was eroded
away each day.
13. Reflection and Discussion
โข Have students reflect on the observations they made in the lab.
โข How do the collection bottles compare:
โข How much sediment is present in each bottle?
โข The colors and clarity of the water in the collection buckets?
โข What do these results tell us about:
โข The power of water?
โข The use of cover crops on a field?
โข Why is protecting the soil important to a farmer?
โข Is there evidence of erosion present around your school?
Investigate your school grounds and identify erosion processes that
are occurring. Using your knowledge of erosion, what are some
ways that you can slow or stop the erosion that is occurring?
14. Careers that focus on soil erosion!
โข Agricultural inspector
โข Agricultural specialist
โข soil and plant scientist
โข Crop production specialist
Operational Definitions help us be able to compare apples to apples not apples to oranges.
Making sure that everyone has a clear picture of the topic is vitally important to having constructive conversations.
Because GMO is such a polarizing term most scientists donโt even use the phrase since the vast amount of the public already has preconceived, and often incorrect definitions of the term.
One approach might be to look at each word in this important phrase.
This will be our operational definition.
Have students use the information they have gathered to sort the six techniques into the category of GMO or Non-GMOโฆ.
There is really no right or wrong answer at this point, students should use the criteria in the definition to help group them.
Use leading questions such as โSo how is DNA changed?โ or โDoes it matter what changes the DNA?โ to help guide students.
Pay close attention to the timelineโฆ Where would you put each of these methods?
When did we start the domestication of crops?
When did we start choosing the genes in our crops?
Let your students move around any of the card they feel should be moved into a new group.
Ask them some more leading questions : โWhen we select plants to grow as crops how do we choose? What controls those traits?โ
Clearly some of these techniques have been used long before we knew anything about DNA specifically.
We didnโt find out about DNA structure until 1952 and it still took several years before we fully understood the importance of DNA to heredity.
Not all of these techniques require the same level of technology to achieve.
The key is specifically the number of genes that are changed at once.
Traditional techniques have the potential to change thousands or hundreds of thousands of genes at once. With this type of breading you cannot choose to target one specific gene without possibly effecting many others. This of it as one good but thousands of possible bads tooโฆ. This process can take a long time, with many many crosses before the desirable combination of traits occurs, if ever at all!
Genetic Engineering uses technology to specifically isolate one gene or one small set of genes to confer the a single desirable trait. Since only one gene is altered or inserted you donโt have to worry about any additional changes to the rest of the genome.
