Module 6: Crops

Goals

• Describe key features of categories of crop plants and how they are adapted to environmental and ecological factors.
• Explain how soil and climatic features determine what crops can be produced in a location, and how humans may alter an environment for crop production.
• Classify environments as high or low resource environments and interpret how both environmental and socio-economic factors contribute to crop plant selection (coupled human-nature systems); and the pros and cons of the cultivation of various crop types.

Learning Objectives

After completing this module, students will be able to:

• Define annual and perennial crops and list some examples of annual and perennial crops.
• Distinguish and explain why annual or perennial crops are cultivated in high resource or resource-limited environments.
• Explain some ways that farmers alter the environment to produce annual or perennial crops.
• Name some major crop plant families with some example crops.
• Explain the nutrient significance of legumes.
• Describe key plant physiological processes and how climate change may influence crop plant growth and yield.
• Classify major crop plants into types, by plant families, temperature adaption, and photosynthetic pathways.
• Formulate an explanation of the advantages and disadvantages of producing annual and perennial crops.
• Interpret what environmental, ecological, and socio-economic factors influence what crops farmers produce.
• Distinguish some environmental, ecological, and socio-economic the advantages and disadvantages of producing types of crops.

This crops module could be used in other courses to introduce undergraduate students to crop plants. It was designed, however, to follow modules of this course that introduce soils, climate, and water. The two-part module is intended for one week of classroom sessions, or a blended online course; but could be taught as an online course. We piloted the module in a blended course in which students read the material and completed the activities of the first part of the module online. Students also read the second part of the module online and then we met for one 75 minute classroom session. In the classroom, we discussed students' completed formative assessments, talked through quiz questions they had difficulty with, and briefly reviewed important course themes. Then students worked on the summative assessment in the classroom with a classmate, and instructors offered assistance.

This module introduces students to crops and their key characteristics that determine their climatic and soil resource adaptations, as well as socio-economic factors that influence their production through:

• Reading the course pages and watching videos embedded in the course pages (on the Internet).
• Completing the embedded activities
• Some outside reading on websites that are included and linked to within the course pages.
• A formative assessment activity that asks students to use a online NASS geo-spatial map of US crops and land use, as well as soils, topography, and climate maps to interpret why the top two crops dominate in two different states.
• A summative assessment that asks students to view the FAO list of the top world food commodities and classify the crops of top 15 FAO world food commodities, analyze which four have increased the most in production since 2000, and to interpret what might explain the increase in their production.

Students can complete this module in the classroom, online, or in a blended format. If the module is used for a class that meets two or three times a week, students can initiate the formative and summative assessment towards the end of class with or without a classmate, and completed assessments can serve for discussion and clarification in a follow-up class meeting.

• Student Materials - Module 6: Agroecosystems: Crops

As with the other modules in this course, defining and keeping the same due dates for the weekly online quiz and the formative and summative assessments can help students get into a routine of reading all of the module pages and completing assignments prior to class, helping them to gain more from the classroom meeting. If the module is used in a classroom, the formative and summative assessments can provide activities with real world data to engage students in active learning with classmates.

In the piloted blended course format, the online quiz and formative assessments were due prior to the classroom meeting. In class, we spent some time discussing and clarifying points of confusion from the online quiz and formative assessment, and this appeared to be helpful, particularly to students who did not have a background in plant or crop science. Themes of the module were briefly reviewed, and depending on how much clarification was needed, about one-third or more of the class time was allotted for students to work on the summative assessment with a partner or in groups of three. The group work provided students an opportunity to discuss their ideas, ask questions, and collaborate in the analysis.

What students found difficult

For beginner students, the pace of learning about a number of crop characteristics and advance to higher-level learning can be challenging. Applying the new knowledge to interpret how climate, soils, and markets together determine which crops are grown in a given region requires integrating lots of information, and a good understanding of key crop characteristics. Some outside readings were removed from the original piloted course module to help students focus on fewer key concepts.

In the formative assessment, students tended to rely on climatic factors to interpret which were the dominant crops in a state. To help students understand and consider how topography and soil influences crop selection, a US topography map and website that describes soil types was added to the formative assessment, and students must describe the topography and soils of the two states they selected. In the blended class, we reviewed the formative assessment and clarified which are perennial crops and the factors that explain their dominance in a some landscapes.

Many of the first and second year undergraduate students were not familiar with doing calculations with data in spreadsheets. To enable them to spend more time interpreting the data, we provided students with the completed calculations of the top 15 FAO commodities in a spreadsheet. The spreadsheet, which can show students how the percent change is calculated, is included with the instructor assessment tools and can be updated in future years.

Many students thought that increased human sugar consumption (and high fructose corn syrup production) explained the growth in sugarcane and corn production, likely because they did not read the crop case studies about corn and sugarcane. The module case studies document the significant increase in sugarcane and corn production for bio-fuels, and the use of corn for livestock feed. To allow more time for students to complete the course materials, some course reading assignments have been removed. Further, instructions at the beginning of the summative assessment state that students should complete the corn and sugarcane case study readings and video watching prior to starting the assessment; question three in the summative assessment also refers students to these course materials.

Reflections

This module introduces a number of crop science concepts and requires students to complete and understand the reading and activities to advance to the data analysis and interpretation stages. To assist students in understanding the module concepts, instructors could review and discuss examples from regions that students are familiar with to illustrate how climate, soil and socio-economic factors influence which crops are produced. Students can also present and discuss their answers to the formative and summative assessments with their classmates, with assistance from the instructor.

This module has two assessments:

• Formative Assessment: USDA National Agricultural Statistics Survey Geo-spatial Map Crop Scape Annual & Perennial Crop Analysis and Interpretation of Advantages & Disadvantages Crops Formative Assessment
• Formative Assessment Grading Key (Instructors access only
  Crops Formative Assessment Grading Key -- private instructor-only file
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• Summative Assessment: Analysis of FAO ranking of the Top 15 World Food Commodities Crops Summative Assessment
• Summative Assessment Grading Key (Instructors access only:
  Crops Summative Assessment Grading Key -- private instructor-only file
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  Crops Summative Assessment Grading Key

  
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Reading materials that are online and embedded in the course pages for students to read:

• Virginia Cooperative Extension: The Organic Way - Plant Families
• Penn State Extension: Seasonal Classification of Vegetables
• Plant & Soil Sciences eLibrary: Transpiration: Water Movement through Plants
• National Climate Assessment Report: Introduction and Section 1 Increasing Impacts on Agriculture
• USDA: Background: Corn

Additional references

Sterling, T. M. Transpiration in the Plant and Soil Sciences ELibrary: http://croptechnology.unl.edu/pages/informationmodule.php?idinformationmodule=1092853841

Taub, D. 2010. Effects of Rising Atmospheric Concentrations of Carbon Dioxide on Plants. Nature Education Knowledge 3(10):21

Tilman, D. 1988. Plant Strategies and the Dynamics and Structure of Plant Communities. Monographs in Population Biology. Princeton University Press, Princeton, NJ.