Soils and Hydroponics Management

Unit 9

AgriScience 1

PLANT GROWING MEDIA

Media definition: material that provides nutrients and support through plant root systems.

Soil Defined:

Soil is the mineral and organic matter that supports plant growth and is a mixture of rock particles, organic matter, living forms, air and water.

Mineral matter- 45%

Air

Water

OM5%

Soil- Planet Earth

Water- 66.7%

Land- 33.3%

Soil- Agricultural land

Water- 66.7%

Non Ag 24.4%

Ag – 8.6%

Water- 66.7%

Non Ag 24.4%

Grazing-5.7%

Crops- 2.9%

Soil- Land Use in IOWA

All Land- 93.7%

Land in US- 6.2%

Iowa- .1%

Forest 4.9%

Minor 2.7%

Transportation 3%

Soil-less Media

Media Mixes Perlite Vermiculite Peat moss Sphaghnum moss Sand Compost Wood chips, barks Water- Hydroponics

Soil Formation

Climate Living Organisms Parent Material Topography Time Weathering

Climate

Temperature Chemical reaction rates Growth of fungi, bacteria, plants

Rainfall

Increases erosion rate

Increases leaching

Living Organisms

Decomposers- fungi and bacteria- aid in organic matter breakdown.

Plants- add organic material to soil Earth worms- help create soil structure and

breakdown plant residue.

Parent Material

Residual Mineral

Igneous Sedimentary Metamorphic

Organic Peat

Transported Glacial till-ice Alluvial- water Loess- wind blown Colluvium- gravity

added by water Lacustrine- lake

deposits

Topography

Time

Organic matter builds up soil becomes more productive

Organic matters decreases and more leaching occurs

Young to old soils

Weathering

Identifying Land Areas and Capability Legal description-location Old-Use a Soil Survey NEW-Digital Map resources

Legal Description

A legal method of describing property for recording on deeds.

2 major systems used Metes and Bounds Rectangular survey

Metes and Bounds

Used in the East and Southwest in early settlement.

Uses major landmarks as a marking system.

Many disputes when landmarks changed.

Rectangular Survey

Adopted in 1875 Latitude and longitude

based. Baselines and principal

meridians 5th meridian is our

principle meridian.

Townships

Laid out starting at the intersection of principle meridian and baseline.

6 miles square 50 feet shorter on the

north boundary. Correction lines every

24 miles

Townships

36 square miles 1 mile square each numbered

Sections 1 square mile 640 Acres further subdivided and described by halves and quarters

Build a Legal Description

Start with smallest fraction section township county State

Land Capability

Land is more than soil

Natural and artificial characteristics of an area to be used for agricultural or other purposes

Includes renewable and nonrenewable resources plus improvements

Land

The surface of the earth not covered with water

Maybe temporarily or permenently covered with water

A pond for aquaculture is considered land

Cropland

Used for growing crops

Crops grown typically improve the tilth of the land

Arable land

Land that can be used for row crops

Can be tilled Alternatives include

pasture and forest crops

Major Characteristics of Cropland Soil - Large impact on productivity. Soil

texture, nutrients and internal structure Climate - average of water conditions over a

long time Topography - form or outline of the surface of

the earth Water supply - amount of water available for

crops

Subsurface conditions - Soil textures, hardpans

Pollution - can prevent plant growth

Alternative Uses

Best land use is determined by how the land will give the most benefits to people.

Which use will give the highest returns

What will happen if productive cropland is used for other purposes?

Land Improvement

Four common practices to improve arable land Irrigation Erosion Control Drainage Forming (land forming)- surface is smoothed

or reshaped.

Capability Factors

Characteristics of land that determine its best use Surface texture

proportion of sand, silt, clay down to about 7 inches

three major classifications sandy loamy clayey

Soil Tilth

Physical condition of the soil that makes it easy or difficult to work Poor tilth has hard clod Maybe very wet or

very dry

Internal drainage

Permeability- movement of water and air through soil

Directly related to nutrient content Classified as very slow, slow, moderate and

rapid water quickly soaks into sandy soil with high

permeability soils with clay have slow permeability

Soil Depth

Thickness of the soil layers Requirement depends upon type of crop to

be produced Four soil depths are used

very shallow - less than 10 inches shallow - 10 to 20 inches moderately deep - 20 to 36 inches deep - over 36 inches

Shallow soils are often the result of erosion

Erosion

Loss of topsoil by wind or other forces Four categories

very severe erosion- 75% or more and large gullies are present

severe erosion - 75% of soil has eroded but no large gullies present

moderate erosion- 25 to 75% of soil has eroded with small gullies present

none to slight erosion - less than 25% of soil has eroded and no gullies are present

Slope

The rise and fall of the elevation of the land

Measured in percents Important in determining the best use of

the land

Surface Runoff

Water from rain, snow, or other precipitation that does not soak into the ground

Can be reduced by conservation practices chopping stalks terraces ground cover

Land Capability

Suitability of land for agricultural uses.

Usage should not cause damage to the land although nutients maybe removed

Land Capability Classes

Assigning a number to land

Eight classes used I to VIII with I being the

best arability Class I to IV can be

cultivated V to VIII tend to have

high slope or low and wet

Classes

Class I - Very good land Very few limitations deep soil and nearly level can be cropped every year as long as land is

taken care of Class II - Good land

has deep soil may require moderate attention to

conservation practices

Class III - moderately good land crops must be more carefully selected often gently sloping hills terraces and stripcropping are more often

used Class IV - fairly good land

lowest class cultivated on hills with more slope than class III

Class V - Unsuited for cultivation can be used for pasture crops and cattle

grazing, hay crops or tree farming often used for wildlife or recreation areas

Class VI - Not suited for row crops too much slope usually damaged by erosion with gullies can be used for trees, wildlife habitat, and

recreation Class VII - Highly unsuited for cultivation

has severe limitations permanent pastures, forestry, wildlife slope is usually over 12 percent large rock surfaces and boulders may be

found very little soil present

Class VIII

Cannot be used for row crops or other crops

often lowland covered with water

soil maybe wet or high in clay

aquatic crops maybe grown there

used for waterfowl habitat

Physical, Biological, and Chemical characterisitics

Unit 9

What is a Soil Profile?- a view of a cross section of soil 0 Horizon-located on

surface, mostly O.M. A Horizon-Called

Topsoil, good amounts of O.M. and minerals.

B Horizon- Known as Subsoil, Less O.M.

C Horizon- Mostly parent material, does little for plant growth.

R- bedtrock

Soil Profile-

Differences in layers based on:Organic matterTextureColorStructure

Soil Color

Determined by 2 main things Organic matter Mineral content

What is soil texture

It is the relative sizes of the different soil

particles.

The major Soil Texture Classes

Sand-largest particle

Silt-medium size particle

Clay-smallest particle

Characteristics of aSandySoil

Characteristics of a SiltySoil

Characteristics of a Clay Soil

Using the Soil TextureTriangle

What is Soil Structure?

Sand, silt and clay particles combine with one anther to form cluster called aggregates.

The way in which aggregates or clusters are arranged is referred to as soil structure.

Soil Structure Categories

Media Amendments

Terms and definitions Essential Nutrient- Element necessary for

plant growth and reproduction, for example: nitrogen, phosphorus, and potassium.

Deficiency- Plant condition where an essential nutrient is not sufficiently available.

Symptom- A visual sign or condition that results from a deficiency: symptoms aids in diagnosing a deficiency.

Chemical Elements Essential To Plant Growth

Non-mineral- air and water Carbon (C) Hydrogen (H) Oxygen (O) Nitrogen (N)

Mineral- from the soil Primary

Nitrogen (N) Phosphorus (P) Potassium (K)

Secondary Calcium (Ca) Magnesium (Mg) Sulfur (S)

Micronutrients Iron (Fe), Boron (B), Manganese

(Mn), Copper (Cu), Zinc (Zn), Molybdenum (Mo), Clorine (Cl)

10 Essential Elements Essential Elements

Carbon (C) Hydrogen (H) Oxygen (O) Phosphorus (P) Potash (K) Nitrogen (N) Sulfur (S) Calcium (Ca) Iron (Fe) Magnesium (Mg)

C. HOPKINS CAFÉ Mighty Good

Functions of Nutrients for plant growth Carbon, Hydrogen, and oxygen are needed in

the plant processes of photosynthesis of photosynthesis and respiration.

Approximately 95% of weight of plants comes from products of photosynthesis

Primary Nutrient Functions

Nitrogen (N) Gives green color to plant Induces vigorous , rapid growth in plants Increases protein and yield Aids and promotes seed and fruit development Nitrogen constitutes 80% of the atmosphere, yet it

is one of the most critical elements for plant growth.

Plants cannot utilize N as a gas, it must be combined with other elements.

Primary nutrient deficiency symptoms Nitrogen (N)

Stunted and Spindly

Yellow, yellowish green or light green in color in foliage (chlorosis)

Older leaves affected first, starting at the tip and moves along the middle of the leaf.

More Primary Nutrient Functions

Phosphorus (P) Important to germinating seedlings Contributes to early maturing crops

Necessary for seed and fruit formation

Stimulates root growth

Primary nutrient deficiency symptoms

Phosphorus (P) Stunted Growth

Very dark green color

Purple leaves or portions of leaves in advanced stages

Older leaves affected first

Primary Nutrient Functions Cont.

Potassium (K) Necessary for production and translocation of

carbohydrates

Produces plumper seeds

Controls Water intake and respiration

Stiffens straw and stalks

Primary nutrient deficiency symptoms Potassium (K)

Shorter plants

Bronzing or browning of leaf color

Lodging (bending of the stem) occurs Leaves show yellow to brown coloring along

leaf margins followed by complete browning.

Deficiency Continued

Other conditions besides deficiencies may cause abnormal plant growth.

Cold, wet weather, lack of sunlight, disease, insect damage, and improperly applied chemicals are examples.

More Terms and Definitions

Fertilizer- Natural, manufactured, or processed material or mixture of materials that contains one or more of the essential nutrients; availible in: dry form liquid form gaseous form

Fertilizer Terms

Analysis- Percentage water soluble content of nitrogen (N), phosphorus (P) expressed as P2O5, and potassium (K) expressed as K2O in the fertilizer.

Brand- Trademark of the company which produced the fertilizer.

Complete Fertilizer- Fertilizer which supplies all three primary nutrients, (N,P,K)

Factors that Influence Fertilizer Use Chemical and physical condition of the soil

Crop to be grown

Climatic Conditions

Time

HYDROPONICSGrowing plants without a soil media.

Hydroponic methods

Aggregate culture Nutriculture Aeroponics Continuous flow

culture

Aggregate culture

Nutriculture

Aeroponics

Continuous flow culture