Soil Properties


Soil color

can be used to indicate the organic content and fertility of a soil and/or the type of minerals and elements that are in the soil

Munsell Color Chart

use to determine the color of the soil through a chip which consists of hue, value, and chroma


intensity or brightness of a color


Darkness or lightness of a color


redness or yellowness of a soil


Usually the result of alternating periods of reduction and oxidation caused by seasonally fluctuating water tables.

soil texture

the soil quality that is based on the proportions of soil particles

coarse fragment

Not considered part of fine earth fraction which are commonly gravel, cobbles, and boulders


visible without a microscope and are rounded or angular in shape. May appear white due to quartz and brown due to other minerals. Feels gritty and considered non-cohesive.


Not visible without microscope.Feels smooth and floury. Easily washed away by flowing water highly erosive


Flat plates or tiny flakes. If suspended in water, will not settle. Pore spaces are very small and convoluted. Movement of water and air very slow.

Textural Profile

aid in looking for the translocation of clay.

Soil structure

The arrangement of primary particles into secondary particles, units or peds. Describes the clustering of soil particles into aggregates of certain size, shape and stability.

Single grain

A type of soil structure that shows little or no tendency to adhere to other particles.


A type of soil structure which are composed of aggregates not over � inch in diameter. Lie loosely and are readily shaken apart. Characteristics of many surface soils


A type of spheroidal soil structure that is porous, may be separated from each other in a loosely packed arrangement


A type of spheroidal soil structure that is very porous


A type of soil structure characterized by relatively thin horizontal peds or plates. Often inherited from the parent materials, especially those laid down by water or ice


A type of soil structure that ranges from a fraction of an inch to 3 or 4 inches in thickness. Usually confined to the subsoil and their state of development and other characteristics have much to do with soil drainage, aeration and root penetration

Angular blocky

A type of blocky soil structure characterized with sharp edges of the blocks and the rectangular faces distinct

Sub-angular blocky

A type of blocky soil structure with the corners that are mostly rounded (sub rounding has occurred).


A type of soil structure characterized by vertically oriented aggregates or pillars that vary in length and may reach a diameter of 6 or more inches. Commonly occur in subsoil horizons in arid and semi-arid regions


A type of prism-like soil structure with tops of the prisms that are relatively angular and flat horizontally.


A type of prism-like soil structure with pillars with distinct rounded tops


A type of soil structure that shows little or no tendency to break apart under light pressure into smaller units.


The mutual attraction clay and organic molecules


microscopic clumps of clay

Aggregate stability

The ability of soil aggregates to resist disruption when outside forces are applied (usually associated with water).


It represents mass (weight) per unit volume of a substance

Particle Density

the mass per unit volume of the soil particles which are not affected by pore space and does not change easily

Bulk density

The mass of dry soil per unit volume, including the air space


The percentage of the total volume of a rock or sediment that consists of open spaces.It directly influences soil water movement

Hydraulic conductivity

Property of soil that describes the ease with which water can move through pore spaces


Process by which water on the ground surface enters the soil


Pores that are too large to have any significant capillary force. Full of air at field capacity.


Pores filled with water at field capacity


Pores that are filled with water at permanent wilting point. Suction is required to remove water

Adsorbed water

also known as hygroscopic water. Held on the surface of the particle by powerful forces of electrical attraction and virtually in a solid-state of very small thickness. Cannot be removed by oven drying at 110 o C.

Water at permanent wilting point

Water that can be removed by oven drying but not by air drying

Capillary water

held by surface tension, generally removable by air drying

Gravitational water

Removable by drainage, can move in the voids between soil grains

Chemically-combined water

In the form of water of hydration within the crystal structure. Not generally removable by oven drying

Maximum retentive capacity

When all soil pores are filled with water, the
soil is saturated and it is at

Field capacity

Moisture content of the soil after gravity has removed all the water it can. Usually occurs 1-3 days after a rain

Permanent wilting point

Soil moisture percentage at which plants cannot obtain enough moisture to continue growing

Available water storage capacity

Amount of liquid water stored in the soil and subsequently released for use by the plants

Gravitational Potential

Water has a positive energy and can flow out of the soil through the large pores. A point when cohesive forces are not large enough to hold onto the water

Matric Potential

The potential energy of water attracted to soil solids

Soil Moisture tension

Tenacity with which soil holds water. It is a negative pressure and commonly expressed in units of bars

Hand feel method

Soil water content measurement which is a The faster method but is prone to error since it requires experience and can be subjective

Gravimetric method

A direct measurement of soil water content. A sample of moist soil is weighed and then dried in an oven at a
temperature of 105 o C for about 24 hours, and finally weighed again

Electrical Resistance Blocks method

block uses small blocks of porous gypsum, nylon,
or fiberglass, suitably embedded with electrodes. When placed in moist soil, it absorbs water in proportion to the soil moisture content

Neutron Scattering method

A neutron scattering probe contains a source of fast
neutrons and a detector for slow neutrons. When fast neutrons collide with H atoms, the neutrons slow down and scatter. The number of slow neutrons counted by a detector corresponds to the soil water co

Tensiometer method

is a water filled tube closed at the bottom with a porous ceramic cup and at the top with an airtight seal. Once placed in soil, water in the tensiometer moves through the porous cup into the soil until water potential is the same as the matric water pote

Soil consistency

Ability of soil to stick to itself or to other objects (cohesion and adhesion, respectively) and its ability to resist deformation and rupture


the ability of the soil material to adhere to other objects.


the ability of the soil material to change shape, but not
volume, continuously under the influence of an applied stress and to retain the impressed shape on removal
of the stress.

Atterberg Limits

The arbitrary limits which define the boundaries between the different states of rigidity or fluidity of fine-grained soils.

Liquid limit

The minimum moisture content, expressed as a percentage of the oven dry soil weight, at which the soil will begin to flow when subjected to a small shearing force.

Plastic limit

The minimum moisture content at which the soil can be rolled into a thread one-eighth of an inch in diameter without crumbling and is determined by trial and error.Soil can no longer behave as plastic

Shrinkage limit

Water content in which the soil no longer changes in
volume regardless of further drying

Plasticity Index

The difference between the liquid limit and the plastic limit.