Physical Properties of Soil

Soil Texture

What is Soil Texture?It is the proportion of three sizes of soil particles.

Which are:Sand (Large)Silt (Medium)Clay (Small)

Soil Texture

What is Sand?It is the largest and is further divided into four subcategories.They are:

Very coarse sandCoarse sandMedium sandFine Sand

Soil Texture

Sand it is the largest soil separate and is composed mainly of weathered grains of quartz. Sand is also gritty to the touch.Sand grains will not stick to each other.

Soil Texture

SandWhat will sand do to the soil?

It will improve the soil by improving the water infiltration and aeration

Soil Texture Silt

is the medium sized soil separated.Silt particles are silky or powdery to the touchSilt grains will not stick to one another just like sand grains.Silt is the best soil as it has the ability to hold large amounts of water in a form plants can use.

Soil Texture

Clay is the smallest size soil separate.It is composed of tiny crystalsClay is formed by chemical reactions between weathered minerals to form tiny particle of new minerals.Clay will hold more plant nutrients than any other separate.Clay grains will stick to one another.

Soil Texture

There are 12 textural classes which can be seen in the next slide.

Soil Texture

Pass out picture of triangle and lets see if we can classify some soils.

Soil Texture

1.40% sand 22% clay and 38% silt

What is the soil classified as?

Soil Texture

2.90% sand 10 % clay and 25 % silt

What is it?

Soil Texture

3.30% sand 50 % clay and 15% silt

What is it?

Soil Texture

4.10 % sand 80% clay and 10% silt.

What is it?

Soil Texture

Lets go and texture some of the kits that we have.

See if you can make a ribbon and with which one?Which one feels grittiest?Which one feel powdery?

Soil Density and Permeability

What is Particle Density? it is the density of solid particles only.

Soil Density and Permeability

What is Bulk Density? It is the mass of a volume of undisturbed oven dry soil

BD= Weight dry soil ___________= __G__ Volume dry soil

cm3

Soil Density and Permeability

Example BD:

The core is 500 cubic cm that weighs 650 gramsWhat is the answer?

Soil Density and Permeability

Answer:

BD= 650g______ = 1.3 g/cm3500 cm3

Soil Density and Permeability

Soil PorosityTotal pore space is measured of the soil volume that holds air and water.

SP=wet weight(g) – dry weight (g)_____________________ x100

soil volume (cm3)

Soil Density and Permeability

Example:The soil core before had a volume of 500 cubic centimeters and weighed 650 grams when dry. When wet the same core weighed 900 grams.Calculate Porosity.

Soil Density and Permeability

Answer:900-650_________x100 =50%500

Soil Density and Permeability

What is Permeability? is the ease of which air, water, and roots move through the soil

Soil Density and Permeability

What is Hydraulic Conductivity?Is the measure of the rate of water movement through the soil

Worm Castings

http://www.youtube.com/watch?v=44AvH-fPxp0

Horizons

Horizons

O - Organic matter A- topsoilB-SubsoilC- Parent materialBedrock

Soil Acid

Ph- is a measure of the degree of acidity or alkalinityAcid – is sometimes referred to as sournessAlkalinity is referred to as sweetness

Soil Acid

Soil Acid

Liming- will increase the pH in soilGypsum-Will decrease the pH in soil.Sulfur and Aluminum sulfate will also decrease soil pH.

Nurtrients

Macro-nutrientsN-nitrogenP2O4-Phosphorus

K2O – Potassium

Ca-CalciumMg-MagnesiumS-Sulfur

Nutrients

Micro-NutrientsIronManganeseBoron ZincCopperMolybdenumchlorine