Importance of soil erosion and land degradation

Importance of soil erosion and land degradation

Land degradation

Human land use has degraded half of the vegetated land on the planet. This implies that human land use is the major driver of land degradation. An outcome of this is lower food security through lower agricultural production attributed to lower soil fertility. Also, land degradation results in climate change and increased global warming.
Desertification – spreading of desert conditions to less arid locations is mainly caused by human activities and climatic variations, affecting millions of people’s livelihoods.
Major cause – poorly managed grazing practices result in overgrazing, contributing to desertification and land degradation.

Soil and vegetation interaction

Often a negative downward spiral.

A negative feedback loop (soil degrades vegetation, lack of vegetation degrades soil); Soil degradation has a low fertility level resulting in declined vegetation. On the other hand, lack of vegetation exposes soil to erosion leading to poor soil fertility and hence lower vegetation.

Geological vs accelerated

The geologic process very slow; the soil erosion caused by geological processes occurs naturally without humans’ interference and is extremely slow.
Human-caused erosion represents accelerated erosion and is 10 to 1000 times more destructive than geological erosion.

Grazing, deforestation, plowing hillsides, land development are some of the major human activities that cause soil erosion leading to land degradation, lower crop yields, and climate change.
35 Mg/ha outside NA, 6 Mg/ha in NA; this implies that outside NA soil erosion is high attributed to lower water infiltration rate.

Impacts of accelerated erosion

On-site damages

Topsoil quality decreases; accelerated soil erosion significantly affects the top soil by removing granular aggregates and soil organic matter.

Nutrient loss; Sediments and runoff due to soil erosion resulting in nutrient loss.

Plant disease spread; Soil erosion may act as a carrier of soil-borne disease organisms spreading diseases to new areas.

Off-site damages

Eutrophication; soil erosion results in the accumulation of sodium and phosphorous-rich sediments in water bodies resulting in significant growth of aquatic plants and lower dissolved oxygen rate in these areas.
Pesticides and heavy metals in sediment; soil erosion carries pesticides and heavy metals, which accumulate in sediments, adversely affecting aquatic organisms and human beings.
Sediment

High water turbidity; accelerated soil erosion carries a large volume of suspended solids into water bodies causing high water turbidity.
Raised river levels, more flooding; accelerated soil erosion lead to increased sediment raising river levels causing floods. Also, degraded land has a lower water infiltration rate resulting in more floods.
Conversion of lakes to mudflats; Higher sedimentation due to accelerated erosion may convert lakes to mudflats interfering with the ecological system and loss of biomass.

Windblown dust

PM 2.5 pollution; the fine particulate matter associated with windblown dust due to soil erosion has significant health implications and can affect crops through reduced photosynthetic activity and plant tissue loss.

Maintaining soil productivity

Nutrient loss compensated with fertilizers; it is usually recommended to use organic fertilizers such as manure, preferably 50kg/ha, to restore the lost nutrients.
Sometimes need irrigation because water serves as a medium of plant nutrients availability, enhancing vegetation and hence healthy soil.

Water erosion

The detachment of particles from mass due to surface flow and raindrops is referred to as water erosion.
Transportation downhill mainly through gravity usually occurs when water or rainfall fails to infiltrate the soil resulting in overland flow or runoff.
Deposition at lower elevation occurs when streams carry solid particles as well as dissolved ions to lower elevations.

Raindrops

Hits soil at high speed imparts kinetic energy to soil particles creating pressure forces and strong local shear. The kinetic energy in raindrops, which is the product of impact velocity square and drop mass, signifies rainfall erosivity.

Soil transportation

Raindrop splash initiates water erosion as long as the drop kinetic energy is adequate to detach soil particles.

Raindrop splash can disperse soil more strongly on sloped surfaces because soil stability and cohesion decrease with slope.

Running water is considered to be the main cause of water erosion and soil erosion in general.

When soil water capacity overcomes soil particles, they are carried away from the impact site creating different types of water erosion, including gully, sheet, and rill erosion.

Types of water erosion

Sheet erosion

It is uniform erosion except for pebble columns. It occurs in a wide range of settings such as beaches, coastal plains, and floodplains. It is caused by low substrate permeability, lack of vegetation, and high-intensity rain.

Rill erosion

Creation of small channels of less than 0.3m deep by runoff water in low points. It is an intermediate phase between sheep and gully erosion.

Gully erosion

Expanded rills into large gullies, specifically more than 30 cm deep, results in gully erosion. It results in significant soil loss.

Deposition of eroded soil

Delivery ratio

The amount of soil that enters a stream is divided by the amount eroded. It is expressed in percentage terms and presents the watershed’s efficiency to move soil particles into streams and sediments deposited areas.

Models to predict water erosion

Universal soil loss equation

Annual soil loss = rainfall erosivity * soil erodibility * slope length * slope gradient * cover and management * erosion control practices. It predicts soil loss by rill or sheet erosion, implying that it cannot be used in gully or wind erosion. Also, it allows soil loss comparison between management systems and specific crops in different lands.

Revised universal soil loss equation

USLE updated in the 90s aimed at improving the initial soil loss equation by changing soil erodibility, cover and management, and slope gradient and incorporate more computerized calculations.

Factors affecting rill erosion

Erosivity

Rainfall amount and intensity coupled with steep slopes increase runoff rates providing a pathway for rill erosion to take place.

Erodability

Soil’s inherent susceptibility to erosion

Low infiltration capacity rate results in higher erodability due to increased water runoff.
Structural stability (aggregates!); higher structural stability of the soil resists soil erosion because soil particles are bound together into strong aggregates.

Topography

Length and gradient of slope area have a positive relationship with soil erosion due to increased runoff and its velocity.

Cover

Trees and adequate cover crops reduce raindrop impact on the soil, limiting soil aggregate breakdown, hence lower soil erosion. However, certain agricultural practices such as row cropping and bare soil due to overgrazing result in higher rill soil erosion since the soil are left unprotected from raindrop splashes.

Best management practices

Best management practices such as terrace systems and grassed waterways reduce water flow and protect soil surfaces from rill erosion.

Control of gully erosion

Remediating gullies

Filled, shaped, seeded with grass, and turned to grassed waterway slows water movement and converts runoff into a stable outlet protecting the soil from gully erosion.

Unstable slopes

Soil creep – Also referred to as slow deformation of soil and rocks due to prolonged stress and pressure brought about by erosional wash. Exposed soil should be covered by vegetation and trees to prevent soil creep.
Mudflow – the rapid movement of partially liquefied soil with a higher viscosity and density may result in permanent sediment entrainment. To prevent mudflows, there is a need to plant trees or install debris flow structures in the region.

Wind erosion

Mechanics

Suspension; occurs when fine particles of below 0.1cm size are moved by tough winds.
Saltation; involves particles’ movement characterized by a wide range of short bounces on the soil surface. The particles in this case range between 0.1 and 0.5cm.

Factors affecting wind erosion

Wind velocity and turbulence; remove loose and unprotected soil resulting in wind erosion.
Surface roughness; soil that is rough slows wind speed at the ground level, reducing wind erosion, particularly saltation.
Soil properties; good soil properties such as soil moisture and soil structure are more resistant to wind erosion. On the other hand, poor soil properties are vulnerable to wind erosion because the soil aggregates are weak.
Vegetation; crop residues, and growing crops protect the soil by reducing wind speed and binding soil particles.

Predicting and controlling wind erosion

Wind erosion prediction equation= f(erodibility index*roughness factor*climatic factor* unsheltered distance*vegetative cover)

Control of wind erosion

Soil moisture; increases soil particles’ cohesion preventing wind erosion.
Soil covers; acts as soil shied from wind erosion and binds soil particles.
Tillage; disrupts soil properties making the soil vulnerable to wind erosion. Therefore, covering the soil with residues is recommended during tillage.
Barriers such as slat fences and trees can be used to reduce wind momentum and speed, hence protecting the soil from wind erosion.

Control of accelerated erosion on range and forestland

Erosion on rangeland

Cattle trails and RV ruts enhance runoff and serve as a good source of sediments. To protect this, one needs to stabilize slopes, create vegetation buffer and divert runoff.
Removal of grass and shrubs exposes soil to erosion; hence one is recommended to cover the soil with residues or vegetation instead of living it bare.

Erosion on forestlands

Primarily driven by logging.

Timber harvest; reduces surface cover and disrupts the soil leading to higher runoff and soil erosion. Hence should be discouraged.
Roads and skid trails result in compacted soil contributing to higher runoff and soil erosion. Therefore, runoff should be diverted to better places.

Practices to reduce soil loss caused by timber production

Buffer strips along streams prevent soil movement into ditches and streams and offer an important soil erosion protection strategy.

Construction sites

Cover disturbed soil

Mulch; covering the soil with straw or mulch protect it from rain and wind erosion.
Erosion mat covers bare soils and has been reported to reduce wind, sheet, and rill erosion effectively.
Hydroseeder facilitates quick seed germination protecting the soil from erosion. For construction sites, they can use it for the planting of grass.

Control runoff

Hard armor involves the use of permanent solutions to protect soil erosion primarily caused by runoff.

Trap sediment can prevent the negative impact of soil erosion in off-sites such as water bodies, protecting biomass in these areas.

Tillage erosion

The movement of soil due to land preparation may results in soil erosion by exposing it to wind and water forces.

Conservation tillage

Conservation tillage systems

Chisel plowing leaves trash on the top preventing the soil from erosion.
Stubble mulching covers the soil surface and protects it from soil erosion. Also, it binds together soil particles and conserves soil moisture.
Ridge tillage involves the use of ridge to plant crops, reducing runoff and soil erosion.
No-till does not disturb the soil, implying that it is usually protected from soil erosion throughout the season.

Adaptation by farmers

Vertical tillage involves the mixing of residue and soil with minimal disturbance of the soil. The approach also enhances organic matter decomposition, fostering soil structure and making it more resistant to soil erosion.

Effects on soil properties

Increased soil organic matter

More porosity facilitates water and air movement reducing soil erosion through decreased runoff.
More aggregation enhances soil stability against soil erosion.
More soil biodiversity prevents soil loss by increasing porosity.

Vegetation barriers

Tropical grass terraces are vital in reducing runoff protecting soil erosion.

Enhancing soil health involves promoting biota and organic matter, which is critical in soil erosion protection.
Finding win-wins will be grounded within enhancing soil organic matter since it is good in achieving healthy soil and is climate-friendly.

Get Professional Assignment Help Cheaply

.
Whichever your reason may is, it is valid! You can get professional academic help from our service at affordable rates. We have a team of professional academic writers who can handle all your assignments.
Our essay writers are graduates with diplomas, bachelor’s, masters, Ph.D., and doctorate degrees in various subjects. The minimum requirement to be an essay writer with our essay writing service is to have a college diploma. When assigning your order, we match the paper subject with the area of specialization of the writer.
Why Choose Our Academic Writing Service?

Plagiarism free papers
Timely delivery
Any deadline
Skilled, Experienced Native English Writers
Subject-relevant academic writer
Adherence to paper instructions
Ability to tackle bulk assignments
Reasonable prices
24/7 Customer Support
Get superb grades consistently

How It Works
1.      Place an order
You fill all the paper instructions in the order form. Make sure you include all the helpful materials so that our academic writers can deliver the perfect paper. It will also help to eliminate unnecessary revisions.
2.      Pay for the order
Proceed to pay for the paper so that it can be assigned to one of our expert academic writers. The paper subject is matched with the writer’s area of specialization.
3.      Track the progress
. Receive a paper.
4.      Download the paper
The paper is sent to your email and uploaded to your personal account. You also get a plagiarism report attached to your paper.

 

PLACE THIS ORDER OR A SIMILAR ORDER WITH ASSIGNMENT GURUH TODAY AND GET AN AMAZING DISCOUNT