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