Soil Erosion -C7 Flashcards
are the weathering products
of rocks and minerals
Soils
Soils are living, dynamic system
which forms in response to forces
exerted by:
climate
b. living organisms
c. parent material
d. topography/relief
e. time
The soil is home to a large proportion of the
world’s ____
Biodiversity
It takes 1,000 yearsto form a____cm
thick layer of soil
2.5 cm
Process which lowers the
current or future capacity of
the soil to produce goods or
services.
Soil degradation
Total land area that had been degraded
70% or 21M ha
Physical characteristics of
degraded soil
Low moisture retention
Slow water infiltration
Soil compaction
chemical characteristics of
degraded soi
Low pH (<5.5 pH-strongly acid)
High concentration of soluble toxic ions
(Al, Fe, Mn)
Low cation exchange capacity (CEC)
Low base saturation (Ca, Mg, K)
Low organic matter content and low npk
Caused by natural (due to soil
formation) or can be caused by human activities such as:
a. Continuous application of
ammonium sulfate
b. Intensive cultivation without
addition of nutrients
c. Draining coastal areas
Soil acidification
Removal of fertile organic matter
due to erosion exposes the
______which is generally acidic
and less fertile.
Subsoil
Caused by deforestation, burning
crop residues, conventional
tillage, and overgrazing
Loss of nutrient and organic matter
Continuous removal of
nutrients without addition
in the form of fertilizer
Nutrient mining
Due to saltwater intrusion
and the use of saline
water to irrigate
agricultural fields
- Salinization
Due to indiscriminate use
of agro-chemicals and
accumulation of toxic
heavy metals from the
industry, mining and
agricultural activities
Pollution
Caused by long-term use of
farm equipment in
intensively cultivated lands
and by overgrazing
Soil compaction
A process that transforms
soil into sediments
Soil erosion
Wearing away of a field’s
topsoil by the natural
physical forces of water and
wind or through forces
associated with farming
such as tillage
Soil erosion
Give 5 causes of soil degradation in PH
Soil acidification
Loss of nutrient and organic matter
Salinization
Nutrient mining
Pollution
Soil compaction
Soil erosion
The ff are drivers of soil
erosion except:
- Overgrazing
- Deforestation
- Intensive cultivation
- Improper soil management
- Cultivation of steeps slopes
- Urbanization
- Pollution
- Mining
- Waste disposal
- Pollution
Why Philippines has higher
erosion rates?
Steep slopes
Highly erodible soils-
- High rainfall erosivity-
Poor vegetative cover in cultivated lands
soil erosion that takes place naturally without the
influence of human activities
Geologic erosion
What are the types of erosion?
Geologic erosion
Accelerated erosion
human influenced erosion (e.g., over grazing,
deforestation, plowing hillside up & down)
Accelerated erosion
What are the types of damaged
caused by erosion?
- On-site damage
2.Off-site damage
The ff are on-site damage caused by erosion. EXCEPT:
a. Reduction of soil fertility
b. Reduction of biological activity
c. increases soil compaction
d. Eutrophication
D.
Examplws of offsite damage
A. Spread of plant diseases
b. Eutrophication
c. Water pollution
d. Damages from
sediments
e. Health hazard
f. Periodic flooding
Types of water erosion
Sheet erosion
Rill erosion
Gully erosion
Uniform erosion
from the entire soil
surface
Sheet erosion
Water concentrates in
small channel (rills) as
it runs off the soil
Rill erosion
Advanced stage of rill
erosion
❑ Deep channels that
cannot be erased by
cultivation
Gully erosion
What are the different processes
of water erosion?
Detachment
2. Transportation
3. Deposition
Factors affecting erosion
Rainfall erosivity (R)
2. Soil erodibility (K)
Slope gradient and length (LS)
Cover and management factor (C)
Management factor (P)
• Is an estimate of the ability of soils to resist erosion
Soil erodibility
High levels of OM, granular structure, and sandy
and loamy textured soils are less erodible than silt
and clay textured soil
T or F?
True
• Intense rain have large drop size which results in
Lower detachment of particles
T or f
False- GREATER DETACHMENT
Higher rate of rainfall, the more run off occurs
providing the means to transport detached particles.
T or f
T
Few torrential downpours may result in lesser damage
T or F
F - RESULTS IN GREATER DAMAGE
____ are heavy in bare soil
Soil looses
(Factors affecting erosion)
High infiltration, less run-off and less surface
ponding
Soil erodibility (K)
Soil erosion increases if the soil has vegetative cover of plants and/or crop residues.
T or f
F - • Soil erosion increases if the soil has NO OR VERY LITTLE vegetative cover
T or f
Undisturbed forest and dense grass provide the
best soil protection
T
to reduce most of the erosion on annual roc-
crop land, leave a residue cover greater than
___% after harvest
30%
runoff and sediments
are caught in a tray and
led through pipes to
collecting tanks which
retain all, or a fixed
proportion of the plot
output.
Erosion plots
nails or steel rods inserted
into the ground to
determine which
ground advances and
ground retreats
Erosion pins
soil erosion is measured
by using isotope caesium-
137 (137 Cs). Stable and
uneroded soil accumulate
137 Cs within the upper
soil profile while eroded
soils will lose adsorbed 137
Cs.
tracers/radioisotopes
receiving
reservoir) were dug at the
lower part of the slope to
catch eroded sediments
Catchpits
It allows
generating rainfall with a
known intensity and duration
on an erosion plot in a
controlled manner, making it
possible to quantify
superficial runoff and soil loss,
while at the same time
allowing a very detailed
erosion predictions.
Rainfall simulator
Models to predict erosion
Water erosion prediction project (WEPP)
Universal soil loss equation (USLE) 1970
Revised Universal Loss Equation (RUSLE)
Set of equations that interrelate information
on rainfall, soil, topography, vegetation and
management
• Simulation model that computes on a daily
basis
Water erosion prediction project (WEPP)
Equation of Universal soil loss equation (USLE) 1970
A= RKLSCP
Uses the same basic factors with improved
accuracy of soil-loss prediction
Revised Universal Loss Equation (RUSLE)
Is the protection of the soil against deterioration,
loss, impoverishment or depletion of the soil’s
capabilities
soil conservation
The ff are Mechanical or structural methods on soil and water conservation and erosion control. EXCEPT
- Terracing
- Contour rock walls
- Gabions
- Riprap
- Ground cover
6.Stone wall - Farm ponds
- Check dams
- Ground cover
The practice of plowing,
harrowing, and furrowing
along the contour of the
land
Contour farming
are level lines
across a slope at a
constant elevation
Contours
This practice applies on
sloping land where crops
are grown
Contour farming
Are narrow live barriers
comprising naturally
occurring grasses
❑ Napier grass, guinea
grass and vetiver grass
Natural vegetative strips
(NVS)
T or f
NVS can be integrated with fruit trees, timber trees, banana, pineapple
T
Saan ba me nagkulang?
Charrrrr
leguminous trees are
grown simultaneously with
agricultural/food crops
❑ Generally practiced in areas
with flat to gently rolling
topography
Alley cropping system
are usually
woody species of tress,
shrubs or grasses
established across slope
and along the contours of
an area
Hedgerows
Ideal hedgegrows (atleast 5)
- Ipil-ipil 7. Kakawate
- Sesbania grandiflora 8. Acacia villosa
- Flemingia macrophylla 9. Banana
- Coffee 10. Jackfruit
- Citrus 11. Chico
- Cashew
Distance between contour
lines
▪ Stiffer slope=?
▪ Gradual slopes= ?
Stiffer slope=4-6 m
Gradual slopes= 7-10 m
NVS Reduce run-off and soil
erosion by as much as
97%
T or f?
F - alley cropping
Developed by the Mindanao
Baptist Rural Life Center, Davao
de Sur
❑ Best suited on steep slopes and
in areas with a long rainy season
Sloping Agricultural Land
Technology (SALT
Growing plants of different
height in the same field at
the same time
❑ This is intended to rolling
areas with slopes ranging
from 18 to 30 percent.
Multi-storey cropping system
Example 1: Coconut- coffee-
pine-apple-banana
This example is a type of what Soil conservation strategies?
Multi-storey cropping system
Coconut-pine-
apple-papaya- peanut
This is an example of what Soil conservation strategies?
Multi-storey cropping system
Growing two or more crops
on the same piece of land
✔Cassava-soybean
✔ cassava-corn
✔Corn-peanut
✔Corn-mungbean
✔Coconut-cacao
Intercropping
Planting of different
crops in successions on
the same piece of land
Crop rotation
Planting annual crops with
the second crop planted
after the first has flowered
or nearing harvest
✔Corn with Mungbean
✔ Tomato with Bitter Gourd
✔Long Beans with Okra
Relay cropping
Are series of level land
on sloping land
Terracing
The higher the slope, the
narrower will be the
width of the terraces
T or f
T
Pag pray na makapasar ta
Lord, papasara me. Love u po
Growing of crops to cover the
soil such as kudzu and
centrosema
Cover crops
Tolerates shade and waterlogging, creeping and twining
Calopogonium and centrosema
Permanent structures
which are built in areas with
abundant rocks
❑ A-frame is made to use
contour lines
Contour rock walls
Use of large wire crates
filled with stones acting as
retaining wal
. Gabions
Rock fitted/piled on the top
of each other to form a
retaining wall
Riprap
Used to stabilize hillsides,
road banks and stream banks
Riprap
Designed to prevent soil erosion
that perennially damages roads,
drainage systems, bridges and
mountainsides in the upland region
Coconets
Uses depression on the
farm, especially in heavily
gullied area to impound
water and minimize
potential run-off
. Water impounding dam
Collect and store surface run-off water during the rainy
season for immediate and future use
Water impounding dam
Ways to fertilize? Atleast 5
- Injection
- Surface broadcast (without incorporation)
- Surface broadcast (incorporated)
- Banded application
- Row placement
- Fertigation
- Foliar application
- Side dressing
- Top dressing
- Perforating
- Basal
Used to place liquid or
gaseous fertilizer below the
soil near plant roots
(anhydrous ammonia)
• Advantages: reduce losses
through precise application
of nutrients
• Disadvantages: slow,
expensive (requires
specialized equipment)
Injection
Method by which fertilizer is
applied on the surface across
an entire field.
• Advantages: fast, economical
• Disadvantages: high
nutrients losses, low
uniformity, P efficiency is
only ¼ that of banding
Surface
broadcast
Uniform distribution of
fertilizer on the soil surface
followed by plowing or
disking to incorporate the
material.
• Advantages: reduce losses
compared to broadcast,
improves plant uptake
• Disadvantages: slow, non-
uniform application,
erosion risk
Surface broadcast
(incorporated)
Also known as STARTER APPLICATION . Fertilizer is
applied in bands either to the
side and below the seeds.
• Advantages: high nutrient use
efficiency, jump-starts early
growth, slows nitrification of
N, reduce the risk of leaching
• Disadvantages: costly, slow,
risk of salt burn to plants
Banded
Application
Fertilizer is applied in
continuous bands on one or
both side of the row
• Applicable for crops like
sugarcane, potato, maize,
cereals and etc. sown close
together in rows
Row Placement
(Band Placement)
Distribution with water-
soluble fertilizers and
chemical through an irrigation
system
Fertigation
Application of a small
amount of fertilizer through
direct spraying onto leaves
• Application rate: 0.5% or
below
• Advantages: rapid uptake
• Disadvantages:
phytotoxicity, limited to
small and/or repeated
application
Foliar
Application
When fertilizer is applied
between rows or young
plants to provide a boost
during periods of rapid
growth and nutrient uptake
Side dressing
Broadcast application of
fertilizer on top of growing
crops (e.g., rice, corn,
forage during their
vegetative stage)
Topdressing
Placing fertilizer in 12’’-18’’
holes drilled 18’’ to 24’’ around
the canopy drip line of fruit
trees.
•Cover the holes and fertilizer
slowly dissolves
•Typically done of fruit and nut
trees
Perforating
Applying and incorporating of
fertilizers into the soil before or at sowing
•Done by digging a hole where
fertilizer is applied and then
covered with 2 inches dept of
soil
Basal
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