KENDRIYA VIDYALAYA NO.4

NAME-SANVEG DINKARCLASS-10TH “A”

ROLL NO.1032

GUIDED BY:- RUPA MAM

TOPIC

SOIL THE BASIC & MOST IMPORTANT RESOURCE

DIFFERENT SOIL TYPES DEVELOP IN DIFFERENT

CLIMATES.

Soils-4-1

Image: T. Loynachan

TUNDRA SOILS FORM IN ARCTIC ENVIRONMENTS, HAVE A DARK ORGANIC-RICH UPPER LAYER, AND A MINERAL RICH LAYER OVER FROZEN GROUND.

Soils-4-7Images: Travis Hudson, Alaska/Yukon Society of Professional Soil Scientists

ORGANIC SOILS ARE DARK COLORED, RICH IN DECOMPOSED ORGANIC MATTER, AND FORM IN POORLY DRAINED LOWLANDS SUCH AS SWAMPS AND WETLANDS.

Soils-4-5

Images: Bruce Molnia, Soil Classifiers of Michigan

TROPICAL SOILS ARE REDDISH AND IRON-OXIDE RICH, DEPLETED IN NUTRIENTS, AND FORM IN HUMID AND WARM REGIONS.

Soils-4-4Images: National Cooperative Soil Survey, University of Nebraska

FOREST SOILS HAVE A LIGHT GRAY UPPER HORIZON, A HORIZON RICH IN ALUMINUM AND/OR IRON, AND FORM IN WARM TO COOL HUMID REGIONS WHERE CONIFEROUS FORESTS GROW.

Soils-4-3Image: Bruce Molnia

Image: Soil Classifiers of Michigan

PRAIRIE SOILS HAVE A DARK SURFACE LAYER (HORIZON), ARE RICH IN MINERALS, AND FORM IN GRASSLANDS WIDESPREAD ACROSS EARTH’S MIDDLE LATITUDES.

Soils-4-2

Images: NRCS

Where does soil come from?

•Rocks•Minerals

•Organic Matter

oA

E

B

C

R

TOP SOIL

SUBSOIL

Sagebrush-Cold Desert

WHAT ARE THE MAIN COMPONENTS OF SOIL?

Mineral Matter Air

Water Organic Matter

SOIL COMPONENTSidealized soil

SOIL SOLIDS

WATER FILLED PORES

AIR FILLED PORES

50 %

25 %

25%

Soil Components (volume basis)

Note: clays are microscopic in size !

Soil separate particle diameter (mm)____________________________

Sand . . . . . . . . . 2.0 - 0.05

Silt . . . . . . . . . . 0.05 - 0.002

Clay . . . . . . . . . . <0.002

SAND

SILT CLAY

Clay mineralsphotographedwith an electronMicroscope.

Note: they are plateor flake like andare stacked on topof each other.

They are electricallycharged and act likemagnets that attractand hold plantnutrients.

What causes soil erosion?

WaterWind

No Vegetation

For agriculture soil is important

What are the FACTORSthat make SOIL?

TIME1000’S TO 10,000’S OF YEARS

LAY OF THE LANDTOPOGRAPHY

LIVING ORGANISMSANIMALS AND PLANTS

CLIMATEHOT/COLD, WIND/RAIN

PARENT MATERIALROCKS AND MINERALS

Physical land features

How can we manage soil??Soil Management, the basis of all scientific

agriculture, which involves six essential practices:

proper tillage; maintenance of a proper supply of organic

matter in the soil; maintenance of a proper nutrient supply; control of soil pollution; maintenance of the correct soil acidity; and control of erosion.

WHAT ARE SOME PERACTICES OF SOIL

CONSERVATION?Terracing

Strip CroppingContour Plowing

TillingWind Breaks

Ground Covers

Contour Farming