Unit 5, Lesson 5.8- Conserving Soil and Forests Lesson Outline: 1. Conserving Soil 2. Conserving Forests

1. Conserving Soil
and Forests
UNIT FIVE, LESSON 5.8
BY MARGIELENE D. JUDAN

2. LESSON OUTLINE
Conserving Soil
Conserving Forests

3. EROSION – major cause of soil loss; the
removal of soil by wind and water

4. Soil Conservation Methods
1. Cover crops
2. Strip cropping
3. Terracing
4. Contour farming
5. Windbreaks
6. Dams
7. Crop rotation
8. Fertilizers

5. 1. Cover crops
Crops planted to
cover a whole field
Have fibrous roots to
prevent erosion
Ex. Clover, alfalfa,
oats, wheat, hay

6. 2. Strip crops
Cover crops
(ex. Alfalfa,
hay, etc.) are
planted
between strips
of row crops
(ex. Corn)
Cover crops (alfalfa)
Row crops (corn)
Cover crops (hay, oats)
Row crops (corn)

7. 3. Terracing
Prevents water from
running directly down
the hill
Used on the sides of
hills
Flat areas are dug in
the hillside
Terrace in Guanxi, China

8. 4. Contour farming
Rows are plowed across
(perpendicular to) the
slopes, following the
contour of the land
Rows (contour) ⊥ slope
Used on uneven
landscapes
Flat areas are dug in the
hillside

9. 5. Windbreaks
Usually consists of
rows of tress (serves
as a wall)
Used to prevent wind
erosions
Poplar tress usually
used

10. 6. Dams
Major means of water
conservation
Supplies water for drinking,
irrigation, laundry, etc.
Can be used for generating
electricity (hydroelectric)
Often built in eroded areas
to slow down running of
water and prevent/reduce
further erosion

11. 7. Crop rotation
Growing different crops in
succeeding years
Since plants have diff.
mineral requirements,
planting diff. crops
prevents mineral
reduction
Legumes, such as
clovers, are rotated along
w/ other crops to restore
nitrates to the soil. Four-year crop rotation system

12. 8. Fertilizers
Used to replace essential
soil materials removed by
crops
Two kinds: natural and
artificial

13. Conserving Forests
Forests are a renewable natural resource. However, replacement
of soil is slow and poor cutting causes permanent damage.

14. Uses of Forests
Trees aids in production of
paper, charcoal, turpentine,
and rayon
Forest soils hold large
quantities of water
Roots prevent soil erosion

15. Forest Conservation Methods
1. Sustained-yield tree farming
2. Reforestation program

16. 1. Sustained-yield tree farming
Involves cutting down
trees only in certain areas
of a forest, leaving
surrounding areas
untouched
Three types: block cutting,
strip cutting, selective
harvesting

17. Block cutting
Square areas of forests
are cut
Reseeding takes place
naturally by the
surrounding trees

18. Strip cutting
Strip of trees are cut
between strips of
untouched trees
Usually done on the side
of a mountain
Reseeding takes place
naturally by the
surrounding trees

19. Selective harvesting
Certain trees are marked
and cut, leaving others
undisturbed
Reseeding takes place
naturally by the
surrounding trees

20. 2. Reforestation programs
Cut areas are planted with
seeds or seedlings, of a
particular type
These are generally fast-
growing, disease-resistant
varieties of trees that
replace undesirable trees

21. Assignment:
Answer Unit Test, p. 182-183, Check Your Knowledge

22. Sources:
Science Links 7