EXERCISE 2
STUDYING THE SOIL PEDON
I. INTRODUCTION
We study soil because we want to make the best use of it, particularly as a medium for growing
our crops. It is a resource that provides us with the basic necessities for living. The soil is a natural
body composed of a mixture of organic and inorganic materials and which is formed from
disintegration and decomposition (weathering) of rocks and minerals. It has a dimension of depth,
width and breadth, physical, chemical, and biological properties that were conditioned by varying
degrees of influence of parent material, topography, living organisms, climate, and time.
Because of these various influences, different kinds of soils evolve and develop over the earth’s
surface. These differences are important to us because they reflect to a large extent the capacity of
soils for various uses. Thus, we approach the study of the soil by examining the soil profile which
shows not only the surface but also its lower reaches. We see more evident differences among soils
through the soil profile.
II. OBJECTIVES
After this exercise, the student should:
1. Be familiarized with some important concepts in soil science
2. Have an idea on how soils are formed and how they are differentiated from one another
through the study of the soil profile.
3. Understand the basic nature of the characteristics of soil in general.
III. ACTIVITY
1. Differentiate the following terms. (30 points)
Physical and Chemical Weathering
Physical, or mechanical, weathering happens when rock is broken through the force of another
substance on the rock such as ice, running water, wind, rapid heating/cooling, or plant growth.
While, chemical weathering occurs when reactions between rock and another substance
dissolve the rock, causing parts of it to fall away.
b. Hydrolysis and Hydration
The difference between hydration and hydrolysis is that hydrolysis is the process of breaking of
compounds using water, whereas hydration is defined as the electrophilic addition reaction, and
there is no cleavage of the original molecule. In hydration, the water molecules are added to the
substance.
c. Oxidation and Reduction
EVA MAEYE CAPITULO 1
