Section 4:Erosion Controls

What is the main goal of soil conservation?

reduce erosion to a

level of maximum sustainable agricultural

production without unacceptable

environmental damage

What is soil conservation never trying to force?

A complete cessation of erosion

What is the “maximum allowable soil that can be eroded” known as?

SLT-soil loss tolerance

What SLT is for average erodibility soils?

11 mt/ha or 2-6 tons/ac

Sensitive area slt?

2 mt/ha

Resistant/deep SLT

15-20 mt/ha

What is a theoretical but not practical SLT?

SLT< or = soil formation

What are the 3 classes of acceptable soil loss generally?

very slight, slight, and moderate

Why are the 3 classes of SLT allowed?

Not all locations can manage a very slight erosion rate

WHat are the 4 main strategies to preventing soil erosion

1. have cover

2. increase inflitration capacity of soils

3. improve agregate

4. increase roughness to reduce velocity

What are the 3 big conservation techniques?

1. Agronomic

2. Soil Management

3. Mechanical

1. Agronomic:

--- use of vegetation to protect the soil

against erosion.

2. Soil management

--- ways of preparing the soil to promote

plant growth and improve its structure to

make it more resistant to erosion

3. Mechanical

--- physical structures to manipulate the

surface topography to control the flow of

waterWhat

What benefit does agronomic approach over a mechanical have? (steps of erosion)

Agronomic measures: influence both the detachment and

transport phases of erosion.

▪ Mechanical methods --- effective in controlling the

transport phase but infective with detachment

▪ Preference is always given to agronomic measures

Why is agronic cheaper?

It fits into existing systems and does not require specialized equipment

What are mechanical means used as?

A supplement to agronomic

Why is it hard to get farmers to do erosion prevention?

1. Famers perception

2. Land ownership and labor

3. Access to soil conservation

What level of soil dpeth is needed for AG?

5 M>

Fragipans?

Hard pans below cropping that effect inflitraion

Why might a farmer not have acess to conservation?

Conservation requires money in the form of labor, equipment, seeds, fertilizer, etc that a farmer might not have.

What do farmers worry about with erosion?

How is this affecting my crops productivity?

Why do leasers not do as much soil conservation?

They do not own the land so they won’t see the long term benefits.

WHat is going to increase erosion risks on cultivated lands?

Removal of trees, shrubs, and grasses

What 5 preventable factors severely affect erosion?

o farming steep slopes,

o cultivating up and down hill,

o continuous use of land to same crops

without fallow or rotation,

o inadequate use of fertilizers and organic

manures

o compaction of the soil

What crops provide the least protection?

Row crops, tall trees crops and low growing crops

with large leaves

What creates erosion in grazing land? How can you avoid it?

overgrazing

Plant vigorus plants that can resist droughts

When are forest generally going to have erosion issues?

When they are cleared, otherwise they are great at preventing erosion

When is urban land going to have the most erosion?

When construction is occuring that results in loss of vegetative cover

What is the plant succession chart for minned land?

1. fast growing grasses

2. legumes like clover to fix N

3. Bushes and heartier grasses to create cover

What should roads do?

Create casthcments and harvest topsoils to be spread back later

SLT is

the maximum permissible rate at

which soil fertility can be maintained over

20-25 years

Why are mechanical not effective alone?

They do not prevent detatchment