soil erosion
detachment and transportation of soil particles by the forces of water/wind
process that transforms soil into sediment
geologic erosion
natural process that wears down topographic highs and fills in topographic lows through deposition of eroded sediments
accelerated erosion
exceeds normal geologic erosion
soil and natural vegetation are disturbed by human activity, 10 to 100 times more destructive
characteristics of soil susceptible to erosion
- low water infiltration capacity
- low OM content
- poor (unstable) structure
- on steep hills
- hydrophobic characteristics
effects of soil erosion
- loss of soil productivity
- sediment pollution
- loss of water
- flooding
- environmental degradation
loss of soil productivity
topsoil erodes, B horizon exposed. lower foliage production, low water infiltration, and greater run-off
sediment pollution
eroded sediment is rich in fertilizer/pesticide, it can upset the ecosystem at its deposition
loss of water
decrease capability to hold water
flooding and environmental degradation
flood in lower areas
destroys the environment
off-site effects of soil erosion
a. siltation of dams, lakes, rivers
b. flood, soil, and water pollution
type of erosion based on agent
- water erosion
- rainfall or splash erosion
- runoff or scour erosion - wind erosion
- erosion by ice
mechanics of soil erosion
- detachment or loosening of soil particles caused by flowing water or raindrops
- transportation of soil particles by floating, rolling, dragging, and/or splashing
- deposition of particles at some place in lower elevation
causes of soil erosion in the PH
a. steep slopes (3/4 of land is hilly to mountainous)
b. highly erodible soils
c. high rainfall erosivity (intense and long rainfall)
d. poor vegetative cover in cultivated lands
why should soil erosion be minimized
- sustain or improve crop yields
- reduce drainage costs maintenance
- retain nutrients and chemical where applied
- reduce hazards and catastrophe
- help improve water quality
type of erosion based on sequential occurrence
- sheet erosion
- rill erosion
- gully erosion
- stream channel erosion
factors affecting degree of erosion
- rainfall
- soil erodibility (texture, structure, bulk density, porosity, infiltration, and water retention
- topography
4 vegetation - cropping practices
- soil conservation practices
how to minimize soil erosion
- maintain good soil structure
- protect soil surface by adequate crop and residue cover
- use special erosion control practices
principles in soil conservation
- reduce runoff velocity
- increase in water infiltration and water holding capacity
- reduce of raindrop impact
- increase in soil porosity and aggregation
soil cosrvation practices
- contour farming
- cover cropping
- alley cropping
- terracing, rock wall, mechanical barriers
- contour ditches, grassed waterways
- farm ponds, check dams
- reforestation
- agroforestry
- multiple cropping, mixed planting
