Conserving Soil and ForestsUNIT FIVE, LESSON 5.8BY MARGIELENE D. JUDAN

LESSON OUTLINEConserving SoilConserving Forests

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

Soil Conservation Methods1. Cover crops2. Strip cropping3. Terracing4. Contour farming5. Windbreaks6. Dams7. Crop rotation8. Fertilizers

1. Cover cropsCrops planted to cover a whole fieldHave fibrous roots to prevent erosionEx. Clover, alfalfa, oats, wheat, hay

2. Strip cropsCover 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)

3. TerracingPrevents water from running directly down the hillUsed on the sides of hillsFlat areas are dug in the hillside

Terrace in Guanxi, China

4. Contour farmingRows are plowed across (perpendicular to) the slopes, following the contour of the land Rows (contour) slopeUsed on uneven landscapesFlat areas are dug in the hillside

Perpendicular 90

5. WindbreaksUsually consists of rows of tress (serves as a wall)Used to prevent wind erosionsPoplar tress usually used

6. DamsMajor means of water conservationSupplies 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

7. Crop rotationGrowing different crops in succeeding yearsSince plants have diff. mineral requirements, planting diff. crops prevents mineral reductionLegumes, such as clovers, are rotated along w/ other crops to restore nitrates to the soil. Four-year crop rotation system

8. FertilizersUsed to replace essential soil materials removed by cropsTwo kinds: natural and artificial

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

Uses of ForestsTrees aids in production of paper, charcoal, turpentine, and rayonForest soils hold large quantities of waterRoots prevent soil erosion

Forest Conservation Methods1. Sustained-yield tree farming2. Reforestation program

1. Sustained-yield tree farmingInvolves cutting down trees only in certain areas of a forest, leaving surrounding areas untouchedThree types: block cutting, strip cutting, selective harvesting

Block cuttingSquare areas of forests are cutReseeding takes place naturally by the surrounding trees

Strip cuttingStrip of trees are cut between strips of untouched treesUsually done on the side of a mountainReseeding takes place naturally by the surrounding trees

Selective harvestingCertain trees are marked and cut, leaving others undisturbedReseeding takes place naturally by the surrounding trees

2. Reforestation programsCut areas are planted with seeds or seedlings, of a particular typeThese are generally fast-growing, disease-resistant varieties of trees that replace undesirable trees

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

Sources:Science Links 7