(http://esseacourses.strategies.org)
Crops Investigation #11
Goal:
Students will understand that the nature of agriculture is such that nutrients are constantly being removed from the soil and that
good farming practice requires that these nutrients be replaced.
Objectives:
Students will be able to:
- explain the impact that agriculture has on biogeochemical (nutrient)
cycles
- compare and contrast organic and inorganic fertilizers
- explain what crop rotation is, how it is carried out, and why is an important farming practice
Standards Met:
Overview:
Students will use the resources to learn about fertilizers and crop rotation.
Materials:
- resources or access to the internet
- crop rotation worksheet to be completed by each student
(C2_rotation_sheet.doc)
Resources:
Actions:
Prior to the lesson:
- Investigation 10 has been completed, including the student homework in which students begin researching a crop plant.
During the lesson:
- Begin by reviewing the concept of nutrient (biogeochemical) cycles. Discuss
the following question. “What happens to the cycle if you remove the plants from the carbon cycle, the nitrogen cycle, or the hydrologic cycle?”
Lead students to the realization that agriculture disrupts these cycles.
- Expand on the previous discussion. “If agriculture disrupts
nutrient cycles, especially through agriculture's removal of nutrients from
the soil, how is it possible to farm the same piece of land for a long
period of time?" This should result in a discussion of
sustainable agriculture. Explain what sustainable agriculture is and
some of its practices. The types of practices discussed may vary with
the amount of time that the instructor chooses to spend on discussion and
local practices. Two key practices should be discussed because they
directly relate to the module: fertilizer application and crop rotation.
- “How can the farmer replace the lost
nutrients?" The answer to this is simple: the farmer must
apply fertilizer. Discuss the two types of fertilizers: organic and
inorganic. Have the class develop a list of pro's and con's of each
fertilizer type. (Resources 1-3) When group presentations are made to
propose farming practices, fertilization of the new land will need to be
discussed in order for the land to be farmed sustainably. An
explanation of the major nutrients found in fertilizers (N-P-K)(resource 4) should be
included in the discussion.
- Nutrient depletion of the soil is a big deal for the farmer
because plants get all of their nutrients from the soil. Once the soil
is depleted of nutrients, it becomes useless to the farmer because plants
will be unable to grow. Crops remove nutrients from the soil.
"Is there any way, other than adding fertilizer to the soil, to put
nutrients back into the soil? Is there any way to slow the loss of
nutrients from the soil?" The answer to this
question is crop rotation. Explain/Discuss the basics of crop rotation
(what it is, how it can put nutrients back into the soil, how it slows
nutrient depletion, etc.). (5)(6)(7)
- Have the students use the resources to find different crop
rotation schemes. As an in-class assignment or for homework, have each
student determine how the crop plant they have been assigned would fit into a crop rotation
scheme. Note that not all crops are rotated (for example, berries and
tree crops like apples). When group presentations are made to propose
farming practices, crop rotation in the new land may be a relevant farming
practice to discuss in order for the land is to be farmed sustainably.
- This assignment should also be made available to the class as was
the assignment from Investigation 10.
Extensions:
- If access to the internet is available, students can research their
plants instead of using the resources provided.
- Additional sustainable agriculture practices could be discussed like
organic farming or "no-till" farming.
Assessment:
Students must determine how the crop plant that they have been assigned would
fit into a crop rotation scheme. This can be done as an in-class
assignment or for homework.
Reflection:
Please write a reflection after you teach this lesson to help us make improvements. Reflections should be e-mailed to j.okeefe@moreheadstate.edu and c.wymer@moreheadstate.edu. If you also complete student reflections, please include these as well.