1999-02-05_GENERAL DOCUMENTS - M1977493 ‎(7)‎

• Permit No: M1977493
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Date: 2/5/1999
• Doc Name: The Nature and Properties of Soils, 8th Edition
• From: Climax
• To: DMG
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

52 PHYSICAL PROPERTIES OF MINERAL SOILS Ch. 3 Sec. 3:8 PORE SPACE OF MINERAL SOILS 53
2.0 TABLE 3:4. Bulk Density and Pore Space of Certain Cultivated Topsoils and
Coarse textured soils of Nearby Uncropped Areas"
(e.g.,SANDS and SANDY LOAMS)
Fine-textured soils Bulk Density Percent Pore Space
},
- 1.75 (e.g.,SILT LOAMS and CLAYS) y `
r,
Years Cropped Uncropped Cropped Uncropped
Soil Type Cropped Soil Soil Soil Soil
E Hagerstown loam(Pa.) 58 1.25 1.07 50.0 57.2
o� =r Marshall silt loam(Iowa) 50+ 1.13 0.93 56.2 62.7
j t 5 E Nappanee silt loam(Ohio) 40 1.31 1.05 50.5 60.3
Cn 'i� Av. 19 Georgia soils 45-150 1.45 1.14 45.1 57.1
z
w
p From Lyon et al.(6).
J
m OTHER WEIGHT FIGURES. When the bulk density of a soil is known in terms
1.25 of grams per cubic centimeter, its approximate dry weight in pounds per
cubic foot may be found by multiplying by 62.42, the standard weight of a
cubic foot of water. Clayey and silty surface soils may vay from 65 to 100
pounds to the cubic foot; sands and sandy loams may show a variation of
1 ° Very tight Very loose 75 to 110 pounds. The greater the organic content, the less is this weight.
:
COMPACTNESS OF SOIL ZONE =Very compact subsoils, regardless of texture, may weigh as much as 125
FIGURE 3:8. Generalized relationship between compactness and the range of bulk
F _-pounds per cubic foot. The figures quoted are on a dry weight basis.
The actual weight of a soil also may be ex re
densities common in sandy soils and in those of finer texture. Sandy soils generally g U ssgd ltI tprma olran acre_foot,
-textured soils. For
referring to volume of soil I acre in extent and I foot deep. The weight of
are less variable in their degree of compactness than are the finer } g a
)i ss than an all soils,the surface layers are more likely to be medium to loose in compactne acre-foot of surface mineral soil may range from 3 to 4 million pounds of
dry substance. The figure most commonly used, however, is 2 million or
are the subsoils.
sometimes 2.5 million pounds as the weight of average surface'soil to a depth
;of 6 to-7 inches.This is considered an acre furrow Comparable weight
>b-figures expressed in metric units are 2.2 to 2.8 million kilograms per hectare.
j!! TAALE 3:3. Bulk Density Data for Certain Wisconsin Profiles
1 Marathon Miami Spencer Superior
Silt Silt Silt Clay t3:8. PORE SPACE OF MINERAL SOILS
Horizon Loam Loam Loam Loam
',The pore space of a soil is that portion occupied by air and water. The
Plow layer 1.34 1.28 1.38 1.46 .amount of this pore space is determined largely by the arrangement of the
Upper subsoil 1.49 1.41 1.55 - 4olid particles. If they lie close together as in sands or compact subsoils, the
Lower subsoil 1.59 1.43 1.66 1.66 r ;,'.>jotal porosity is low. If they are arranged in porous aggregates, as is often
Parent material 1.72 1.49 1.63 -
,-th cas
e se in medium-textured soils hi in organic mat
ter, the ores ace r
`' � g P P per
;t `unit`volume will be high.
{ ° From Nelson and Muckenhirn(7). ; The validity of the above generalizations may readily be substantiated
. �bytthe use of a very simple formula involving particle density and bulk
density figures.The derivation of the formula used to calculate the percentage
Data presented in Table 3:4 show this relationship very well. These data of total pore space in soil follows:
are from long-time experiments in four different states,the soils having been
1 under cultivation for from 40 to 150 years. Cropping increased the bulk bulk density
%solid space x 100
density of the topsoils in all cases. t^: = particle density
�,, i