Soil Resources

The importance of

Soil resources------Hallie

• You may not think of soil as a resource .Yet many things you need depend on healthy soil. Food production depends on corps. Paper comes from trees. All this plants we rely on need healthy soil.

The soil is-----Home to organisms（ plants 、 animals ， and others ）

Great integrator

Waste decomposer gas exchanger

Source material for construction,Medicine, art, etc.

Filter of water and wastes

Medium for plant growthMedium of crop production

Soil Erosion• Due to the severity of it

s ecological effects, and the scale on which it is occurring, erosion constitutes one of the most significant global environmental problems we face today.

Soil Erosion• Sedimentation of aquatic ecos

ystems• Soil erosion (especially from ag

ricultural activity) is considered to be the leading global cause of diffuse water pollution, due to the effects of the excess sediments flowing into the world's waterways. The sediments themselves act as pollutants, as well as being carriers for other pollutants, such as attached pesticide molecules or heavy metals.

Soil Erosion• Land degradation• Water and wind erosion are

now the two primary causes of land degradation; combined, they are responsible for 84% of degraded acreage.Each year, about 75 billion tons of soil is eroded from the land—a rate that is about 13-40 times as fast as the natural rate of erosion.Approximately 40% of the world's agricultural land is seriously degraded.

Soil Erosion• Airborne dust pollution• Soil particles picked up durin

g wind erosion are a major source of air pollution, in the form of airborne particulates—"dust". These airborne soil particles are often contaminated with toxic chemicals such as pesticides or petroleum fuels, posing ecological and public health hazards when they later land, or are inhaled/ingested.

Soil Erosion• Tectonic effects• The removal by erosion

of large amounts of rock from a particular region, and its deposition elsewhere, can result in a lightening of the load on the lower crust and mantle. This can cause tectonic or isostatic uplift in the region.

Desertification

Definitio

• lower land productivity caused by overgrazing, seasonal drought ,and climate change.

Areas affected• rylands occupy approximately 40–41% of Eart

h’s land area and are home to more than 2 billion people. That about 1–6% of the inhabitants of drylands live in desertified areas, and that a billion people are under threat from further desertification

Cause• because of the population growth,many of the

se areas are inappropriately opened to development, when they cannot sustain human settlements.Over-cultivation also causes the nutrients in the soil to be depleted faster than they are restored. Improper irrigation practices result in salinated soils, and depletion of aquifers.

• Overgrazing removes this vegetation causing erosion and loss of topsoil.

• Also it is caused by over farming.

Deforestation

Definitions

• the destruction of forests.

Cause• The overwhelming direct cause of deforestation is ag

riculture. • One study found that population increases due to hig

h fertility rates were a primary driver of tropical deforestation in only 8% of cases.Other causes of contemporary deforestation may include corruption of government institutions,the inequitable distribution of wealth and power,[15] population growth and overpopulation and urbanization.[19] Globalization is often viewed as another root cause of deforestation.

Soil Affects• the majority of deforestation was caused

by industrial factors, including extractive industries, large-scale cattle ranching, and extensive agriculture. Tree removal on steep slopes with shallow soil thus increases the risk of landslides, which can threaten people living nearby.

Control

• Reducing emissions, Farming, Forest management, Sustainable practices, Reforestation

• The area of the soil erosion has topped 1.50 ～ 1.60 million square kilometer

• Making eroded soil decrease by 5 billion tons every year• The area of soil erosion takes up 1/12 of the world’s total （ 600

billion tons ）• It is equivalent to destory cultivated land 1000000 mu• The area of the soil ersion accounts for 80% ～ 90% of the total land area of our country

Our country is one of the countries that have the most serious problem with soil ersion in the world !

Definition

Reason

Harm

Management

Catalogue

• Soil erosion ： The washing a

way of soil by the flow of water or wind.

soil erosion

nature artificial

1.climate

2.soil

3.vegeta-tio

n

1.land is plo

wed

2.over-grazi

ng

Reason

Harm desertification

Farm-land

Destory soil Loss nutrient

Degradate quality

Reducter produce

RiverSilte hevealy Raised riverbed

threaten the lives and property of people

Enviro-nment

deteriorate the environment

aggravate nature calamity

Harm

Management

Engineering measure （ build levelterrace ）

Engineering measure （construct a dam ）

Agronomic measure Agronomic measure 11

Agronomic measure Agronomic measure 22

Governance affect

Topsoil

Sean

Topsoil• Definition• The mineral- and nutrient-rich portion of the soil is called topsoil.

• Good topsoil• Absorb and hold water that plants need.• But also allows some water to drain.• Have rich nutrients and low salts.

• Produce Good topsoil is produced by many years of interactions tween soil and

plants. This process take a long time.

Topsoil• Damage• Topsoil can be damaged or lost quickly.• For example:• There is a large Plain. • But it was poorly farmed for many years.• Then a very big drought hit there.• Because of these two factors, the topsoil was eroded and the crops fail.• Then this area become like a desert.• This area was called “dust bowl”• Lots of people lost homes and jobs.

The interactionof soil and plants

Jason

The layers of soilA(O): plough layer, By farming, fertilizer, irrigation affect the most strong soil horizon, the thickness of about 20 centimeters commonly.A:plough pan, located in the plough layer under, thick about6 to 8 cm. Typical plough pan is very tight, porosity small, poor permeability.B:eluvial horizon, The soil fertility mainly concen-trated in this layer, general is cultivated land soil plough layer.C:parent material horizon, The clastic rock weathering residues or transported

content structure, much less by biological effect, soil effect is not obvious, basically maintained a parent rock characteristics.

Elements plants need• Major elements: O,C,H take up 96% (O45%

、 C45% 、 H6%), N 1.5% 、 P 0.15% 、 K 1.5% 、 Mg 0.2% 、 Ca 0.5% 、 S 0.1% ,

• Trace elements: Fe 、 Zn 、 Cu 、 Mn 、 B take up 0.01%-0.00001%.

Elements in soil• It is hard to measure how much elements this area

have, or to say whether this area is nutritive because different plants need to absorb different elements. But, in general, what they need are basic equal.

interaction• Plants can benefit from the soil. They can absorb

water, nutrients, salt, which help them grow faster and stronger. Also, there are some useful elements can prevent several disease. Plants also need to fix their roots deeply in the soil. When plants die, they will be decomposed and become the nutrients back to the soil, which helps other living things to survive.

interaction• They also have Interdependence. That is, lost either

soil of plants, the other one will fast die. The plants’ exist help the ground not expose under the sun, or the water will lost quickly. Also, plants can fix nutrients into the soil, if there’s no plants, and wind blow strongly, the nutrients will lost quickly, too. For atmosphere, no plants means no water evaporation, that area is much hotter. For other living things, they will extinct or have to move out. Thus, plants and soil decide everything.