Soil physical properties

what is the silt particle size class?

.002 to .049 mm in diameter

what is the sand particle size class?

.05 to 2.0 mm in diameter.

what should good ag soils be less than under bulk density?

1.5g/cc

In structure, what are the man made aggregates called?

Clods

What are the 4 soil structure types?

Massive, blocky, platy, and granular

What is are the 7 physical properties of soil?

Texture. structure. bulk density. water holding capacity. infiltration rate. aeration. strength. color. temperature.

What are the texture classes?

all soils are combinations of the three main particles sizes, no pure sands, silts, or clays. (must have different particle sizes to form horizons)

what is soil color?

an indicator of soil properties

what do white soil layers indicate?

areas of salt accumulation

what can heavy equipment do to soil?

cause compaction

What is aeration?

chemical compound and the amount of soil air.

what are some of the soil colors?

darker soils, red or orange soils' white layer, blue, green, greyish rust colored.

What is structure?

defined as the arrangement of soil particles into aggregates.

what do red or orange soils indicate?

high oxidation of minerals and possibly low fertility

What is aeration higher in?

higher in CO2 than surface air because of respiration of soil microbes. have a greyish coloration and can occur due to flooding and high clay content, compacted soils and impermeable layers.

how is water capacity calculated?

in inches of water per food of soil depth. almost all gravitational drainage done in 3 days.

What is infiltration rate?

inches per hour of water that sinks into the soil from the surface.

what is bulk density?

is weight per unit volume

what is the clay particle size class?

less than .002mm in diameter

what do green, blue or greyish soil indicate?

long periods of low oxygen like in bottoms of lakes.

define massive?

no organized arrangement of particles, no real structure. very poor soil for ag little water penetration.

Define blocky?

particles arranged so that peds form angular blocks upon drying. is fair for ag, often is high in clay content.

Define granular?

particles organized so that peds shaped into small, somewhat spherical bb to marble sized particles, best for ag soils. mostly loamy soil textures.

define platy?

particles organized so that peds shaped like plates or in layers. fair to poor for ag . can form impermeable layers.

In structure, what are the natural aggregates called?

peds

according to the Buoyucous measurement, what is the rate for sand, silt and clay to settle?

sand in 30 seconds. silt in 2 hours. clay in days to never depending on temperature

what does rust colored soil mean?

shorter periods of low oxygen like in ephemeral lakes or flood basins.

what is soil dispersion?

sodium and sodium chloride causes particles to repel each other

how are texture and soil structure different?

soil structure can change by farming, erosion, climate.

what is used to determine the soil texture?

soil texture triangle, silt, clay, sand percentages

What is texture?

texture is defined by percent of sand, silt, and clay.

what soil temp?

the only physical property that is constantly changing.

What is soil strength?

the soils responses to mechanical forces.

How is the infiltration rate measured?

using infitrometers.

what do darker soils indicate?

usually higher in organic matter

what is water holding capacity?

weight of water per unit volume of soil after gravitational drainage

what is soil bulk density?

weight per unit volume of dry soil