Soil Science
Chapter 11. Organisms and ecology of the soil
(*: important concept)
Zueng-Sang Chen (陳尊賢)
Tel: 2369-8349, soilchen@ccms.ntu.edu.tw; http://Lab.ac.ntu.edu.tw/soilsc/
Printed on Nov 20, 2004
11.1 Diversity of organisms in the soil
 General classification (*Table 11.1, p450)
11.2 Organisms in action
 *primary producers, primary consumers, secondary consumers, and tertiary consumers (Fig 11.1, p453)
11.3 **Biomass and metabolic activity
 *Biomass: (Table 12.3, p457)
 ** relative number and biomass of fauna and flora (400-5,000 kg bacteria /15cm/ha, 400-5,000 kg
Actinomyces /15cm/ha, 1,000-15,000 kg fungi/15cm/ha, and 10-500 kg algae/15cm/ha, 100-1500 kg
earthworms/15cm/ha) (Table 11.4, p458)
 ** autotrophic and heterotrophic (Table 11.5, p459)
11.4 *Earthworms
 ** influence on soil fertility and productivity (Table 11.6, 11.7, Fig 11.7, p461-462)
 30-300 per square meter in arable soils
11.5 Ants and termites
 *mound-building activity (Fig 11.9, p465)
 termites so not generally have a beneficial effects on soil productivity
11.6 Soil micro-animals
 *nematodes (Fig 11.11, p466)
 * protozoa (Fig 11.15, p469)
11.7 Roots of higher plants
 *Rhizosphere (根圈), allelopathy (毒他植物)
11.8 Soil algae
11.9 Soil Fungi
 *molds (黴菌) (Penicilliums, Mucor, Fusarium, and Aspergillus)
 mushroom
 ** Mycorrhizae (菌根) (Symbiosis, and non-symbiosis; ecto-mycorrhiza and endo-mycorrhiza)
 arbuscular mycorrhizae (叢囊菌根)
11.12 Conditions affecting the growth of soil microorganisms
 *Oxygen, moisture, temperature, pH, Eh, etc.
11.13 **Beneficial effects of soil microorganisms
 *organic materials decomposition, breakdown of toxic compounds, inorganic transformation, N
fixation, Rhizobacteria, and plant protection.
Discussion:
1. Four main types of metabolisms carried out by the soil organisms
2. two parties of symbiosis.
3. the function of earthworms activities
4. definition of rhizosphere
5. Explain and compare the tillage and manure application on the abundance and diversity of soil organisms
6. What are some of the potential benefits and potential risks involved with the release of genetically
engineered modified organisms (GEMs) into the soils?