Assignment 9: Soil: Foundation for Land Ecosystems

Chapter 11

Soil and Plant Growth

1. List five management considerations for productive topsoil.

a. ________________________________ b. ___________________________________

c.________________________________ d. ___________________________________

e. ________________________________

2. What constitutes the base of the food chain in soil ecosystems? ____________________________________

3. The soil environment must supply the plant or at least its roots with ______________________________,

__________________________________, and _________________________________.

4. Three mineral nutrients required by the plant are _____________________________________, _________________________________________, and _______________________________________.

5. The original source of mineral nutrients is from the breakdown of __________________________________ through the process of ________________________________________.

6. The process of weathering is fast enough to sustain vigorous plant growth without other sources.

(True or False)

7. In natural ecosystems, the greatest source of mineral nutrients for sustaining plant growth is from ____________________________________.

8. In addition to the frequency and amount of precipitation, the amount of water that is actually available to plants will depend on:

a. the amount of water that infiltrates versus running off. (True or False)

b. the amount of water that is held in soil versus percolating through it. (True or False)

c. the amount of water that evaporates from the soil surface. (True or False)

9. Most plants have access to oxygen through the (roots, stems, or leaves).

10. List two ways of depriving plants of sufficient oxygen.

a. ___________________________________ b. _____________________________________

11. pH is a measure of relative _____________________________ and ____________________________.

12. Most plants require a soil environment that is

a. acidic b. basic or alkaline c. close to neutral

13. Neutral is expressed by a pH of ________________.

The Soil Community

14. List the five ingredients required of productive topsoil.

a. ________________________________________________________________________________

b. ________________________________________________________________________________

c. ________________________________________________________________________________

d. ________________________________________________________________________________

e. ________________________________________________________________________________

15. The workability of clay soils will be (more or less) difficult when compared to sandy soils.

16. As soil organisms feed on the detritus and reduce it to humus, their activity also mixes and integrates humus with mineral particles, developing what is called soil _______________________________.

17. Who gets what in the symbiotic relationship between some plants and mycorrhizae?

Plants: _____________________________________________________________________________

Mycorrhizae: ________________________________________________________________________

18. Green plants support soil organisms by being the direct or indirect source of all their food.

(True or False)

19. Soil organisms support green plants by making the soil more suitable for their growth.

(True or False)

20. The second tropic level of the food web in a soil ecosystem is

a. producers b. detritus c. humus d. decomposers