Topic 5: SUSTAINING THE SOIL
What might happen if we lost most
of our soil?
- soil acts as an anchor for plants and a
community for billions of residents
- soil contains nutrients, air, and water for
plants
HOW SOIL DEVELOPS
READ PAGE 150HOW
AND EXLAIN
FIVEDEVELOPS
FACTORS THAT
SOIL
DETERMINE HOW SOIL DEVELOPS
FIVE FACTORS THAT DETERMINE HOW SOIL DEVELOPS
1.
1. Parent Material - mineral matter (rock clay or soil) from
which the soil is developed
2.
2. Climate - determines the kinds of plants that will grow
and how quickly they will decompose. Warmth and
3. moisture break down plant and animal matter and change
it to humus (holds the water)
3. Vegetation - determines the type of organic matter in soil
4. and protects the soil from erosion
-4.different
soils develop
different vegetation and
Water - brings
new soilunder
and nutrients
water conditions
5. Time - all these processes happen over a long time
SOIL HORIZONS
- different soils develop under different
vegetation and water conditions
SOIL: A LIVELY COMMUNITY
- healthy soil contains an amazing collection of
creatures
- decomposers break down plant and animal tissue ,
forming humus.
FOUR KEY DECOMPOSERS
NAME
HABITAT
WHAT DO THEY DO?
Bacteria
- healthy grasslands
- breakdown dead plant
and animal tissue
Fungi
- includes molds
and mushrooms
- found in forest oils and
where soils are cooler and
acidic
- make nutrients available
to plants
- soil anywhere
- decompose organic
matter and forming
humus
Microscopic
actinomycetes
(special type of
bacteria)
Earthworms - found in healthy soil
- produce casts that are
richer in nutrients and
bacteria
NUTRIENTS IN THE SOIL
- soil contains these elements for plant growth
♣
♣
♣
♣
♣
♣
Nitrogen – turns leaves green
Phosphorus – newly planted seeds, stem
of plants and flowers
Potassium – flowers and seeds
Sulphur
Calcium
Magnesium
Nitrogen
- makes leaves green
Phosphorus
- newly planted seeds and stems
need extra phosphorus
Potassium
- needed for flowers
Fertilizers
- sulphur. calcium and nitrogen are
usually present in soil.
- nitrogen, phosphorus and potassium
are often added in fertilizer.
- on a bag of fertilizer the three numbers indicate the
percentage of each nutrient
5% Nitrogen
10% Phosphorus
5% Potassium
NUTRIENTS IN THE SOIL
- soil contains these elements for plant growth
♣
♣
♣
♣
♣
♣
Nitrogen – turns leaves green
Phosphorus – newly planted seeds, stem
of plants and flowers
Potassium – flowers and seeds
Sulphur
Calcium
Magnesium
CHALLENGES AND SOLUTIONS
SALINIZATION: SALTY SOIL
What is it?
- CRUST OF SALT COLLECTED ON THE SURFACE OF
THE SOIL (WHITE CRUST AROUND A SLOUGH)
What happens when soil is salty?
- HIGH LEVEL OF SALT IN SOIL HAS THE SAME EFFECT AS
DROUGHT CONDITIONS
What causes salt in the soil?
- TOO LITTLE VEGETATION
- TOO MUCH WATER (EXCESS IRRIGATION)
How can we solve this problem?
- REPLANTING AREAS SO PLANTS USE UP WATER
- MONITOR IRRIGATION
- LINED WATER CANALS TO PREVENT
WATER FROM DRAINING INTO GROUND
ORGANIC MATTER AND EROSION
WHAT IS THE PROBLEM WITH THE LOSS OF
ORGANIC MATTER IN THE SOIL?
- SOIL EROSION
- SOIL IS LESS ABLE TO HOLD AIR, NUTRIENTS AND WATER
WHAT HAS CAUSED THIS PROBLEM?
- EXCESS CULTIVATION OF SOIL TO CONROL WEEDS AND
PREPARE SOIL FOR SEEDING.
WHAT PROBLEM DOES THE LOSS OF ORGANIC
MATTER IN SOIL CAUSE?
- DECREASED YEILD OF CROPS
The Path to Reduced Soil Quality
SAVING THE SOIL
NAME FIVE WAYS FARMERS CAN
SAVE THE SOIL?
1. - PLANTING A COVER OF VEGETATION ON
THE SURFACE TO SLOW THE FLOW OF
WATER AND PROTECT IT FROM WIND
EROSION.
2. - ZERO TILLAGE PROTECTS THE SOIL FROM
WIND AND RAIN EROSIONS AND DRYING
- USE SEED DRILLS TO PLANT CROPS
THROUGH THE STUBBLE OF THE PREVIOUS
CROP
3.
PLANT SHELTER BELTS (ROWS OF TREES)
ALONG THE EDGES OF FIELDS.
- REDUCE WIND DAMAGE
- TRAP SNOW TO INCREASE MOISTURE
- PROVIDE WILDLIFE HABITAT
4. RESHAPE SEEDED WATER WAYS TO REDUCE
EROSION FORMED BY HEAVY RAINSTORMS
AND MELTWATER.
5. USE FORAGE CROPS (LEGUMES AND
GRASSES) TO ADD ORGANIC MATTER AND
PROVIDE PROTECTION FROM WIND AND
EROSION.
WHAT IS HYDROPONICS?
- GROWING PLANTS WITHOUT SOIL
- GROWN IN GRAVEL OR ROCK WOOL
HOW CAN THE SOIL IN THE FORESTS BE SAVED?
- leave some trees, branches. stumps in cut areas
- replant forest quickly after trees are cut