Introduction to Soil Chemistry

problems 67
oxide by components in soil, and questions as to whether all the organic matter
is oxidized. Directly measuring the amount of organic matter destroyed is difficult
using this method.
There are still other methods of oxidizing soil organic matter. These are not
generally or commonly used for a variety of reasons, which can be found by
investigating them in the literature [21].
3.8. CONCLUSIONS
Soil biological components are important not only because of their role in
mixing and decomposing both the inorganic and organic components therein
but also in the addition of organic matter to soil. Organic matter is added by
animals, those that live in as well as on the soil, chiefly in the form of manure.
Plants add organic matter from their tops and through their roots. Microorganisms
are involved chiefly in the decomposition of organic matter
deposited by animals and plants. However, they also produce many different
inorganic and organic compounds during the decomposition process. One of
the most important of these components is humus. Analysis of soil organic
matter is accomplished by oxidizing the organic matter using various oxidative
chemical procedures. Animals, plants, microorganisms, and organic matter
in soil will have a pronounced effect on the soil’s characteristics and on procedures
used to analyze it.
PROBLEMS
3.1. Name some common types of animals, plants, and microorganisms commonly
found in soil.
3.2. Explain how animals can change the physical characteristics of soil. Give
some examples.
3.3. In soil microbiology microorganisms are defined by which simple
characteristic? Describe the variety of organisms that have this
characteristic.
3.4. Explain how animals and plants add organic matter to soil and how this
addition is different for these two different groups of organisms.
3.5. What is the rhizosphere, and why is it important?
3.6. What is the difference between a biomolecule and an organic molecule?
3.7. Diagram the breakdown of organic matter in soil and give the products
of this decomposition process.
3.8. Explain how humus is formed in soil and why it is important. Give some
examples.