For the InstructorThese student materials complement the Future of Food Instructor Materials. If you would like your students to have access to the student materials, we suggest you either point them at the Student Version which omits the framing pages with information designed for faculty (and this box). Or you can download these pages in several formats that you can include in your course website or local Learning Managment System. Learn more about using, modifying, and sharing InTeGrate teaching materials. Show
How do soils form in different places?Soil Formation FactorsSoils around the world have different properties that affect their ability to supply nutrients and water to support food production, and these differences result from different factors that vary from place to place. For example the age of a soil -- the time over which rainfall, plants, and microbes have been able to alter rocks in the earth's crust via weathering-- varies greatly, from just a few years where soil has been recently deposited by glaciers or rivers, to millions of years in the Amazon or Congo River Basins. A soil's age plus the type of rock it is made from gives it different properties as a key resource for food systems. Knowing some basics of soil formation helps us to understand the soil resources that farmers use when they engage in food production. Below are some of the most important factors that contribute to creating a soil:
A Summary of Soil Formation: The Global Soils MapThese four factors along with the vegetation, microbes, and animals at a site, create different types of soils the world over. A basic global mapping of these soil types is given below in Fig. 5.1.2 We've attached some soil taxonomic names (for soil orders, categories used by soil taxonomists) to these basic soil types for those who are familiar with some of the terminology of soil classification. We should emphasize that understanding these orders is not essential to your understanding of food production and food systems, as long as you understand how the basic processes of soil formation described above, and the properties of soils described on the next page, contribute to the overall productivity of a soil. You should think about how the soil formation processes affect crop production in your capstone regions of your final project, and you should be able to find resources on how soils were formed in any place in the United States and around the world. Figure 5.1.2. Simplified global soil map classified into broad
categories. Formation and Management Affect a Soil's ProductivityAnother important point is that soil formation processes described above largely determine only the initialstate of a soil as this passes into human management as part of a coupled human-natural food system. Human management can have equally large effects as soil formation on productivity, either upgrading productivity or destroying it. The best management protects the soil from erosion, replenishes its nutrients and organic matter, and in some ways continues the process of soil formation in a positive way. &We'll describe these best practices as part of a systems approach to soil management in module 7. Inadequate human management can be said to "mine" the soil, only subtracting and never re-adding nutrients, and allowing rainfall and wind to carry away layers of topsoil. The next page adds to this description of soil formation by focusing in on the basic properties that affect food production on soils, like acidity and pH which is discussed above. Check Your Understanding: The Nature of Soil and Soil FormationAnswer the following questions on basic properties of soil and factors of soil formation:The two basic types of chemical nature of materials in the solid part of soils (i.e. not air and not water) are mineral and __________. 2. Fill in the blanks using the choices given: Large pores in soil are important for _______________ and medium size pores are important for _____________________. (choices: holding water for plants, drainage) The amount of carbon held in soils globally is (larger, smaller) than the amount of carbon in all the earth's forests. Soils with what type of rock tend to resist the natural process of acidification that happens to soils in many climates? In global comparative terms and considering the global soil map above, a soil in the Northeast United States would tend to be ____________________ (young or old). Which of the following is likely to have a low level of organic matter and why? A dry climate soil or a wet climate soil? Which geographic factor explains why both regions have similar climates?Which geographic factor explains why both British Columbia and the British Isles regions have similar climates? ANS: The warmer temperatures of maritime winds.
Which geographic factor is most responsible for producing this phenomenon?Geography Mid-terms. Which factor most contributed to the change in the settlement patterns of the original inhabitants of Australia?The underlying geography and the location of natural resources had an obvious impact on settlement patterns. Most often this impact had already played out in earlier times and was evident in the settlement patterns of 1911. The climate, soils and distance were key factors in the early development of Australia.
Which physical geographic feature has created a north south division in the settlement pattern of Africa?The Sahara stretches across much of northern Africa creating a formidable barrier and dividing Africa between a Muslim, Arab North and traditional African cultural groups in the south.
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