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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:

Standards Met:

Overview:

Students will use the resources to learn about fertilizers and crop rotation.

Materials:

Resources:

Actions:

Prior to the lesson:

  1. Investigation 10 has been completed, including the student homework in which students begin researching a crop plant.

During the lesson:

  1. 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.
  2. 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.
  3. “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.
  4. 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)
  5. 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.
  6. This assignment should also be made available to the class as was the assignment from Investigation 10.

Extensions:

  1. If access to the internet is available, students can research their plants instead of using the resources provided.
  2. 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.