Bulk Density

%PS -Ov Equation for what?

%AFPS

(1-Db/Dp) X 100

%PS

Mw/Ms = ?

Om, mass of water/mass of dry soil

Om X Db/Dw =?

Ov, volume of water per volume of soil

Ms/Vt Equation for what?

Particle Density

Definition of porosity?

Refers to the percent soil by volume that is occupied by pores rather than solids

Why is air filled pore space important?

Root respiration and gas exchange

Common range for compacted surface & subsurface soils Db?

up to 2.0 g/gm3

Common range for fine textured soil Db?

1.0-1.60 g/cm3

Common range for sandy and loamy sand Db?

1.20-1.80 g/cm3

If the Dp is not otherwise stated, what # do we assume?

2.65 g/cm3

At a density of 2.0g/cm3, pore space is what %?

25%

Ms/Vs Equation for what?

Db, Bulk Density

Do fine textured or coarse textured soils have lower bulk densities? Why?

Fine textured soils. They have more macropores and micropores, better structured in aggregates.

Bulk density is measured in what units?

G/Cm3

Units for Db and Dp ?

G/Cm3

Om stands for what?

Gravimetric water content (mass wetness)

Compacted soil has a ... Db?

Higher

The higher the bulk density, the lower or higher the % pore space?

Lower

The higher the volume in soil, the ... the Db? Vice versus.

Lower

Uncompacted soil has a ... Db?

Lower

Dp equation is what over what?

weight of solids(g)/volume of solids(cm3)

Factors that affect bulk density/particle density

Soil structure & texture, organic matter content, pore space, compaction, tillage

Factors that affect pore space?

Texture, structure, soil biota, tillage

Definition of particle density

The mass per unit volume of soil (solids)

Definition of bulk volume

The volume of solids plus pore space

Definition of bulk density

The weight of dry soil over the bulk volume of dry soil (solids & pores)

Ov stands for what?

Volumetric water content (volume wetness)

Bulk density affects...?

Water movement, air exchange, root growth