THE PHYSICAL ACTION OF LIME
ON CLAY SOILS
A THESIS
PRESENTED TO THE FACULTY OF THE GRADUATE SCHOOL
OF CORNELL UNIVERSITY FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
BY
ROBERT MIFFLIN SNYDER.
December, 1917
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THE PHYSICAL ACTION OF LIME ON CLAY SOLLS
The recent investigations in the field of soil acidity have raised anew
the question of the physical action of lime on the soil. A number of
physical investigations have been conducted in the past, but the recent
progress in certain auxiliary subjects, as colloid chemistry, has tended
to depreciate the value of much of this work, and bring new problems
to the front. The question may therefore be properly considered again:
What is the specific effect of each form of lime on the soil, and how great
is that effect?
Our problem resolves itself into two parts: First, the selection of
desirable methods, and second, their application. Let us first review the
procedures available for the study of the colloidal characteristics of the
soil, and determine wherein their merits and deficiencies lie. The vari-
ous methods may be classified under eight distinct headings, as follows:
Methods for Estimating Soil Colloidality
Flocculation in selution.
1. The suspension method.
Solubility of colloidal material.
2. Fraps Ammonia Method.
3. Van Bemmelen Acid Method.
4. Endosmometer method.
Heat Liberation on Wetting. :
». Pouillet-Mitscherlich Method.
Capillarity and Retentive Power.
6. Hilgard Total Retentive Cup Method.
i. Briggs and McLane Moisture Equivalent Method.
8. Capillary Rise of Water.
9. Percolation of Water.
10. Atterberg Plasticity Method.
Adsorption.
11. Hygroscopic Water.
12. Dye Adsorption.
13. Selective Adsorption of ions.
14. Endell Histological Method.
Volume Change.
15. Expansion Method.
ACKNOWLEDGMENT
The writer takes pleasure in acknowledging his obligations to Professors T. L. Lyou, W. D.
Bancroft. T. R. Briggs, and H. O. Buckman for helpful criticisms and suggestions He is
particularly ‘ndebted to Professor J. A. Bizzell, under the immediate di ection of whom the
work was conducted,
4 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
Penetrability.
16. Penetration Method (Laboratory).
17. Dynamometer Method (Field).
Oxidation.
18. The Oxidation Method.
1. The Suspension Method has been used more extensively than any
other. It consists essentially in making a suspension of the material in
the particular solution to be tested, and observing the time required for
precipitation. For a number of decades the suspension method was the
only means by which the effect of ions on the stability of colloidal ma-
terial could be determined. In the hands of Schulze, Bams, Picton and
Linder, Bodlander, and Hardy, it was of immense assistance in the form-
ulation of the fundamentals of colloid chemistry. The specific action of
various salts, and the valence and mass relations, have been popular sub-
jects for study. The most recent work with clay suspensions has been
performed by Masoni, and by Wolkoff.
Valuable as the suspension procedure has been in the preliminary
studies, the question nevertheless arises whether it should be considered
a legitimate method for correctly estimating the physical effects of salts
on soils. The writer is of the opinion that the precipitation of a sol by
an electrolyte is of little value in gauging the action of the same salt
applied to a soil under natural conditions. In a suspension the forces
inhibiting the neutralization of charges are very small, while in a heavy
soil the internal friction prevents the formation of the large floccules
characteristic of the suspension. Probably in many heavy clays the posi-
tively changed colloidal iron remains indefinitely in approximate con-
tiguity to the negative silicia without neutralization taking place.
A somewhat similar view regarding the inapplicability of the suspen-
sion method is held by Free. He thinks that in the soil, the tension at
the liquid-vapor surface may be the determining factor in precipitation.
2. Fraps has studied the ammonia soluble inorganic soil colloids. He
does not propose his method as a means by which the entire colloidal
content of the soil may be measured.
3. The Van Bemmelen Method for the estimation of soil colloids con-
sists in the determination of the material made soluble on prolonged
digestion with hydrochloric and sulfuric acids. In the hands of Blanck
and Dobrescu, and Vander Leeden and Schneider, the Van Bemmelen
procedure has not yielded significant results. A serious criticism of the
method lies in the fact that erystalloidal as well as colloidal matter may
be rendered soluble.
4. The Endosmometer Method has been used by Kénig, Hasenbaumer
and Hassler for the determination of the absorbed ions in the soil. The
|
THE PHYSICAL ACTION. OF LIME ON CLAY SOILS 5
amount of salts released by the current bears only a very indirect rela-
tion to the amount of colloidal material.
5. The “Pouillet Effect” is another means by which the estimation
of internal surface has been attempted. This method is named after C.
Pouillet, who as far back as 1823 observed that finely divided substances
released heat on wetting. Mitscherlich (1898) was the first to attempt
the estimation of the internal surface of soils by the use of this phe-
nomenon. Several other investigators have since then attempted similar
studies. The fact that heat release in soils may be associated with a
number of factors renders the Pouillet effect of doubtful value.
6. The total retentive power of the soil for water has long been used
as a standard measurement. The early investigators usually allowed
water to rise by capillarity in a cylinder filled with the soil, and then
determined the final percentage present. Hilgard modified the procedure
by using a short column of standard length, but the method still remains
rather inaccurate.
The investigations of Trentler, Wollny, Blanck, and Engels indicate
that calcium oxide increases the total retentive power of the soil. All
these men, however, used excessive applications. The probable error in
the case of Thaer’s work is too high to permit the drawing of conclusions.
Frear thinks that liming has no effect on the total retentive power. The
writer is calling attention in each case to the instances in which limed
soils have been used, for there is no better criterion as to the accuracy
of a physical method, than its sensitivity to small amounts of lime.
7. The Moisture Equivalent Method of Briggs and McLane suggests
itself as a possible means for estimating internal surface. Unfortunately,
the probable error is so high as to probably preclude the measurement
of very small lime applications. Sharp, of the California Station, is using
this method at the present time in his alkali investigations.
8. The capillary rise of water in soil columns has been used by
several investigators as a method for estimating soil colloidality. ne
usual procedure has been to place the lower end of a column of dry soil
in contact with water, and record the speed and total height of ascent.
Mever. Krawkow, Gross. Blanck, and Engels have performed capillary
experiments with lime treated soils. The data, considered as a whole,
is inconclusive. Undoubtedly, internal surface is a factor in capillary
rise, but the additional factors of surface tension and Greree of compac-
tion are exceedingly difficult to control.
9. The speed of percolation of water through soils has frequently been
used as a measure of soil structure. Studies have been conducted by
Vogel, Ebermeyer, Biihler, Blanck, Thaer, and Engels on the influence
of lime on percolation. All agree that lime increases the ease with which
water passes downward. For comparative purposes it is necessary to
obtain a large volume of percolate, and this results in the removal of
6 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
salts from the sample. An objection to this procedure rests in the fact
that the colloidal condition, the factor which we are measuring, depends
on the salt content. A decrease in the amount of adsorbed salts results in
a deflocculation of the soils. Both Mayer and Van Bemmelen noted at an
early date that percolation decreased on prolonged leaching, and the same
thing has been more recently noted by Hall, and by Sharp.
10. The Atterberg Plasticity Method has been proposed solely as a
means of evaluating clays. It has never been applied to the estimation
of internal surface. According to Kinnison, the Atterberg plasticity
figure depends on too many factors to be of value.
11. The term “hygroscopic moisture” has usually been taken to mean
the amount of Water that a soil will absorb in order that its internal
surface be covered with a film one molecule in thickness. However, there
is reason to believe that the thickness of the film is greater than that
stipulated by the definition. Furthermore, the slowness in reaching
equilibrium, and the great effect of temperature on the final result, indi-
cate that much of the water is present in the form of capillary water
located in the interstices of the soil particles. It is more correct to speak
of the phenomenon as “hygro-interstitial moisture,” connoting thereby its
true nature.
The early workers tested out the adsorptive power of soils for various
vapors and gases. All these investigations resulted in the selection of
water vapor as best suited for the purposes in hand. The hygro-inter-
stitial investigations have been conducted according to two general types
of procedure:
1. The first involves the constant passage of water vapor over or
through a soil until equilibrium is reached.
2. The second requires the placing of the sample in an atmosphere
whose degree of saturation is controlled, the moisture being conveyed to
> from the soil by diffusion.
one classical investigations of Ammon and of von Dobeneck belons to
the first type. They conducted the saturated vapor through a U-tube or
some other suitable vessel containing the soil, until equilibrium had been
reached. Both men were concerned with the adsorptive power of the
various soil constituents, and so carefully was their work conducted, that
it remains today our most valuable contribution to the subject.
One of the difficulties with the procedure was the frequency with which
an abnormal condensation of water vapor occurred on the interior of the
containing vessel. This led to the practice of reducing the degree of
saturation of the water vapor. Heiden, for instance, emploved a vapor
apvroximately seventy-five per cent saturated, but he could not obtain
valuable results. Owing to the difficulties of manipulation the subject
was abandoned, and during the nineties no work was done on any phases
of the question.
THE PHYSICAL ACTION OF LIME ON CLAY SOILS iG
In 1903, Rodewald and Mitscherlich proposed a method corresponding
to the second type of procedure outlined above. The soil sample, pre-
viously dried over phosphorus pentoxide, was placed in a container over
ten per cent sulfuric acid until equilibrium was attained. The function
of the sulfuric acid was’to control the degree of humidity and prevent
condensation. This method has been used by a large number of investi-
gators. Engels, Thaer, and Czermack have found that lime, particularly
calcium oxide, decreases the hygro-interstitial moisture. The amounts of
lime which they used, however, were excessive.
Comparisons of the Rodenwald-Mitscherlish method with the other
means of measuring internal surface have been attempted by Tadokoro,
and Stremme and Aarnio. They find a good general agreement between
the different methods. It should be pointed out in this connection, how-
ever, that a good general correlation is to be expected in comparing soils
whose percentages of clay vary widely.
The possibility of the desiccation over phosphorus pentoxide having an
influence on the colloidal material has been pointed out by Ehrenberg
and Pick. They suggest that moist soil be placed in the desiccator or
humidor and allowed to remain until equilibrium is obtained.
There are two main objections to the Rodewald-Mitscherlich method and
its modifications:
1. Too much time is consumed in waiting for equilibrium to be reached
in any particular case.
2. There is a high probable error in the method, due probably to the
fact that diffusion permits only an approximation of true equilibrium
conditions.
Blanck ran soils according to the Ehrenberg-Pick modification in one
instance for a period considerably exceeding one hundred days, at the
end of which time equilibrium had not been reached.
12. The Dye Adsorption Method constitutes one of the standard means
for determining the internal surface of soils.
Undoubtedly, there exists in the soil a great variety of colloidal sub-
stances varying in both chemical and physical condition. Four forms,
namely, iron, aluminum, humus, and silica, have been generally recog-
nized. This classification is of the crudest sort, and undoubtedly comes
far from conveying an adequate conception of the variety of colloidal
materials present. When we recall that the weathering processes usually
increase the amount of colloidal matter, we might expect to find about
as many colloids present in the soils as original rock sources. Rogers has
made a review of the mineral kingdom, and finds a great number of min-
erals to be colloidal in nature. Many of them, we have reason to believe,
exist in the soil, as, for instance, allophane, elemental carbon, opal, hema-
tite, and limonite. Soils of volcanic origin probably contain pyrolusite
and rutile.
8 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
The use of dyes in the identification of minerals has been undertaken |
by Pelet and Grand, Hundeshagen, Dittler and Cornu. Certain dyes are
used which will be adsorbed by specific substances, and thus an attempt
is made to identify the materials present. Unfortunately, it is not always
possible to differentiate between the colloidal and crystalloidal matter.
Furthermore, it is possible that colloids of approximately the same chem-
ical composition may vary in their adsorptive powers for dyes. Such
factors as the amount of water of hydration may quantitatively influence
the results. Rohland and von Possanner find that tale and kaolin vary
widely among themselves as to their adsorptive properties, and according
to Bancroft, the nature of hydrous ferric oxide varies with the method
of preparation.
It is possible that in the soil we have processes which tend to simplify
the nature of the colloidal material. Lacroix, in a study of the decompo-
sition products of the aluminum silicate rocks, concluded that the end
product was hydrous aluminum oxide. Rohland holds the same view. In
fact, it seems necessary to assume an hydrolysis of the silicates in order to
explain the beneficial action following the application of calcium silicates
to the soil. Whether hydrolysis takes place or not, the probabilities,
nevertheless, are that in most soils we have a vast series of colloidal
materials present, each varying somewhat in its qualitative and quanti-
tative adsorptive power. It is, therefore, apparent that any dyestuff is
only very roughly specifie with regard to its adsorbent.
In view of the insolved nature of the subject, there has existed in the
literature the greatest confusion with regard to the use of dyes on soils
and the interpretation of the results obtained. However, the fact that
certain dyes are adsorbed only by certain colloids when prepared in the
pure state, permits our obtaining some idea as to the nature of the
adsorbing material in the field. The weakness of the method consists
in the fact that, owing to the variation in the properties of the colloidal
matter, our evidence is circumstantial at best.
Before proceeding further, it seems necessary to discuss certain factors
influencing dyestuff adsorption, and indicate their relation to soils work.
1. Nature of the dye. The opinion has existed in the soils literature
that all dyes were equally valuable, as long as they were adsorbed. No
idea could be more erroneons. Lyollema in 1905 found that certain dyes
were specific for certain materials. The specificity of dyes hag been
worked out further by Rohland, and Beaumont; subject, of course, to
the limitations reviewed in the preceding pages. We find that the azo
dyes are adsorbed practically not at all. Rohland has tried to correlate
this peculiarity of the azo dyes with certain molecular configurations.
iTe finds safranine and indigo (the leuco indigo white?) to be specific
for humus. Beaumont thinks diamine sky blue is adsorbed by colloidal
aluminum. The tri-phenyl methane dyes are taken up by both humus and
THE PHYSICAL ACTION OF LIME ON CLAY SOILS 9
silica. Methylene blue, while adsorbed slightly by humus and aluminum,
is taken up in such enormous amounts by silica, that it may be rightly
considered specific for the latter. The writer has found eosin to be
admirably adapted for aluminum. No dye has yet been found which is
satisfactory for hydrous ferric oxide. Summarizing, then, we have the
following as the best suited for soils adsorption work.
Hydrous ferric oxide,—no dye.
Hydrous aluminum oxide,—eosin and diamine sky blue.
Humus,—safranine.
Silica,—methylene blue.
2. The concentration of the dye employed should be small. Within
narrow limits, adsorption is a linear function of the concentration. The
curve obtained by plotting the amount adsorbed against concentration
ceases to be linear, however, on increasing the concentration of the dye
solution. Further, the stability of the sol may be affected if the dye is
too concentrated.
3. The dye should be stable irrespective of the reaction of the bath.
All dyes which in alkaline solution are changed into the dye-base or
leuco-base are unsuited for soils which give an alkaline filtrate on wash-
ing. Inasmuch as the great majority of soils render an aqueous solution
alkaline, all colors exhibiting the above characteristics, as the tri-phenyl
methane dyes, for instance, should be discarded. Unfortunately, this
includes the greater portion of the colors used in the past, as crystal,
methyl, and gentian violet, aniline blue, aniline green, aniline red, methyl
green, malachite green, etc. Changing the reaction of the solution after
adsorption is usually not sufficient to restore the color to the dye, since
alkalinity may reduce the dye-base to the leuco form. Oryng, and Adams
and Rosenstein have called attention to the difficulties inherent with the
triphenyl methane dyes. It is not surprising that Gedroits, using crystal
and methyl violet, found no relation between colloidality and adsorption.
Another potential source of error lies in the fact that alkali may unite
with the dye and form a lake. This is what happens in the case of alizar-
ine, one of the dyes recommended by Ljollema. Tadokoro, in selecting a
color for his work, chose eosin, because it was stable in acid or alkaline,
but he overlooked the fact that eosin is specific for hydrous aluminum
oxide. We probably obtain no eosinic lake formation in the case of
adsorption by soils. Too much care cannot be taken that the dye is
stable under all conditions.
4. The reaction of the solution should not affect the adsorption equili-
brium. In the textile industries the amount of dye taken up in any
particular case is largely determined by the degree of reaction of the
bath. The subject is summarized by Bancroft as follows:
The following holds for an acid dye:
10 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
a. The dye is taken up most readily in an acid solution but may be
taken up in a neutral or alkaline solution.
b. A readily adsorbed anion decreases the amount of dye taken up. ~
c. A readily adsorbed cation increases the amount of dye taken up.
The effect of the reaction on dye adsorption has been extensively
studied by Bancroft, and by Pelet-Jolivet and his co-workers. If the
amount of salt in a sample of soil is large, the final equilibrium may be
affected. In order to use the dye method as a measure of internal sur-
face, we must satisfy ourselves by preliminary experimentation that the
salt is present in too small an amount to influence the degree of adsorp-
tion. It is readily apparent that we should use small charges of soil,
particularly. if fertilizers have been added, for the amount of salt per
unit concentration of dye increases directly with the amount of soil
used. Ruprecht and Morse in their ammonium sulfate studies, found
that the amount of dye taken up by the soil was increased after fertilizer
treatment. We have no means of knowing from their work, however,
whether the increase was due to the influence of the ammonium sulfate
on internal surface, or whether it was the result of the changed reaction
of the bath. The effect of the added material on the adsorption equili-
brium has been in the past entirely overlooked in soils work.
5. The protective action of organic matter on colloida] material has
been recognized by a number of investigators. In running experiments
on mineral colloids it is desirable to use soils as free from organic matter
as possible.
13. Selective adsorption has been used by many investigators as a
means of estimating internal surface. Heiden, Parker, and Konig,
Hasenbaumer, and Hassler are only a few of those who have taken the
adsorptive power of the soil for potassium as a measure of the internal
surface involved. The results lose their significance, however, when we
recall that the soil contains a number of different kinds of colloidal
material, each varying in its specificity with regard to adsorption. Thus,
Thaer finds that the potassium ion is not adsorbed by colloidal humus,
and Lokolovskii observes the same thing for the ammonium radical.
Daikuhara believes that the adsorption of the potassium ion is character-
istic of the colloidal iron and aluminum. The possibility of interchange
of bases tends to further confuse the phenomenon. It is, therefore, not
surprising that some workers, as Tadokoro, have failed to establish an
agreement in the results from selective adsorption and some of our other
more valuable methods.
14. The Histological Method for the determination of colloids in clays
was proposed by Endell. The dry clay is boiled in Canada balsam, and
after cooling and hardening it is cut into small sections and colored with
fuchsin. This method has been discussed by Cornu. Owing to the sim-
THE PHYSICAL ACTION OF LIME ON CLAY SOILS iil
plicity of certain other procedures, the histological method has never
come into general use.
15. Expansion methods are nearly as old as soil physics itself. In
1838, Schiibler began work on the subject, and his investigations have
been continued by Haberlandt, von Schwarz, Puchner, and Wollny. The
lime studies of Thaer and Engels resulted in the conclusion that there
was a slight increase in volume on liming. In all the above cases the
soils were allowed to come to dryness before making final measurements.
Tempany (1917) finds that in drying down, internal friction between
the soil particles becomes very great. This raises the question whether
measurements after drying are particularly significant. Brown and
Montgomery, in a study of the dehydration of clays, finds that shrinkage
is no criterion of plasticity. Furthermore, it appears just as objection-
able to make measurements from a dry to a moist condition, as vice versa.
R. O. E. Davis cites data from Wollny in which the latter found that a
dry soil moistened with water expanded six times as much as the same
soil moistened with calcium hydrate solution!
Wolff, and more recently Tadokoro, have studied the swelling exhibited
by soils after being immersed in various reagents. This work is open
not only to the objections already mentioned, but is also subject to the
further criticism that swelling may be specific for the reagent employed.
If expansion readings are made at a constant moisture content, we
largely eliminate imbibitional factors, and may more correctly attribute
differences to changes in soil structure.
16. The cohesion method for the investigation of soil properties was
first used by Schiibler, who added a gradually increasing weight to a
scale pan suspended from the middle of the dry brickette to be tested.
This procedure has been used by Fippin in his investigation of the effect
of lime on granulation. The Schiibler method has been modified by
Puchner, who suspends the scale pan above the knife edge entering the
soil. The Atterberg procedure is essentially the same as that of Puchner,
except that the scale pan is supported by a superstructure. The penetra-
tion method has been used by Cameron and Gallagher, and by R. O. E.
Davis for measuring coherence. The greater portion of their work is
unconvincing because they failed to calculate the probable error of their
determinations. Thaer and Engels have made penetration measurements
in their work, but unfortunately the amounts of lime used were excessive.
It would seem that penetration determinations should be made at a
constant moisture content for essentially the same reasons as in the case
of shrinkage. On bringing to air dryness, certain cementing materials
undoubtedly come into play which are not operative under ordinary con-
ditions.
17. The Dynamometer Method consists in measuring the resistance
offered to the passage of a plow through the soil. A spring is connected
12 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
with a revolving drum in such a manner as to record the traction at any
particular moment. We would expect that the summations of the values
obtained from various lime plats, for instance, would indicate the effect
of the lime on the physical condition of the soil. Work along this line
has been undertaken by Mausberg and by Noll. Unfortunately the prob-
able error involved is so high that experiments must be carried through a
long series of years before significant results are obtainable.
18. The Oxidative Power of the soil has never been used as a method
for the estimation of internal surface. There seems no reason to doubt,
however, that oxidation is in large part a surface phenomenon. The
great ability of colloidal humus and hydrous ferric oxide to cause oxida-
tion, as indicated by the work of Schreiner and his co-workers, would
suggest that oxidation may be a specific and not a general phenomenon.
Aloin is not suited for measurements of internal surface, owing to the
fact that it is catalyzed by alkalies. An aloin solution will “keep” for
only a few hours because of the presence of alkali dissolved from the con-
tainer. An aloin solution will keep indefinitely if a small amount of
acid is added when the solution is first made. The question arises in
this connection whether Schreiner and Sullivan’s study of the oxidizing
power of soil extracts is particularly significant.
Phenolphthalin is nore satisfactory for estimating internal surface. It
is convenient to read, and, unlike aloin, is very stable towards the atmos-
phere. One precaution to be observed, is to avoid the use of a strong
alkali in bringing out the full color of the phenolphthalein before reading.
In a strongly alkaline solution the phenolphthalein is converted into the
colorless leuco-base. Ammonia is a very satisfactory alkali to use in
this connection.
It is frequently desirable to clarify the solution with a precipitant,
just prior to rendering the solution alkaline. If a soil has been rendered
strongly basic by a salt treatment, the humus brought into suspension
may modify the pink color to such a degree as to make a previous precipi-
tation imperative.
DISCUSSION
In the preceding exposition we noted that the analogy between the
suspension method and conditions as they actually exist in the soil, was
not very close. There is no reason to doubt, however, that the funda-
mental phenomena involved are essentially the same, the differences
being simply a matter of degree.. Cameron takes the point of view that
there is no basis for attributing surface action to colloids, and Gedroits
holds a similar opinion, on account of the small colloidal content of any
soil. On taking into consideration the large internal surface involved
en even a slight subdivision of any material, however, it is found unneces-
THE PHYSICAL ACTION OF LIME ON CLAY SOILS 13
sary to stipulate any other action to account for the surface phenomena
which take place.
A consideration of the literature on the effect of lime salis on tloccula-
tion reveals an unusual amount of confusion. The relation of valence to
flocculating power has long been appreciated, but unfortunately invetiga-
tors are just coming to realize that the question of active masses is of
equal importance. For instance, sodium salts of weak acids are floccu-
lents or deflocculents according to the relative concentrations of pre-
cipitant and material being precipitated. This question has been dis-
cussed in detail by Given, Wolkoff, and Wiegner.
Rohland believes that on liming, the precipitating power is due to
hydroxyl ions, and with calcium hydrate, the action is direct. With cases
in which gypsum is applied, Rohland would assign the beneficial result to
the precipitating power of the hydroxyl ions formed on the decomposi-
tion of the salt. Here again, the various colloidal materials present in
the soil tend to further confuse the phenomenon. Pappada finds that
the hydroxyl ion is the most powerful in the precipitation of hydrous
ferric oxide. Rohland’s view would hold in so far as the positive colloids
are concerned, but it would not hold for the negative. A soil suspension
is usually negative, but there is no ground to believe that the colloidal
material in the soil is entirely precipitated by cations or other bodies
positively charged. ;
Ehrenberg holds that the cation is the important flocculating agent.
He ascribes a strong action to the calcium ion, and virtually none to the
hycroxyl. Therefore calcium hydrate is the strongest flocculent of the
lime salts. On increasing the strength of the acid in the salt, the pre-
cipitating action becomes less and less, until in the case of gypsum, we
have practically complete antagonism. Ehrenberg’s theory is better than
Rohland’s just in so far as it better describes the actual state of affairs.
As a matter of fact, both views are extreme. A solution of the question
lies in the recognition of the complex nature of the colloidal material,
and the fact that flocculation is a matter of relative charges, masses,
and valencies.
In past studies on the physical effect of lime on the soil, the tendency
has been to make applications on a percentage basis. For example, a
favorite custom has been to use one per cent of lime, and there is one
instance in the literature in which one part of lime was added to four
parts of soil. In view of the relation of masses to precipitation, and
furthermore, the wide departure from field practice involved, the question
naturally arises whether the results from such experiments are particu-
larly. significant. The work of Blanck, Thaer, and Engels, the lime
studies most frequently quoted, are all open to the objection that the
applications used were excessive. Unfortunately the methods available
for physical studies have not been sufficiently accurate to be used in
14 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
work with comparatively small salt applications. In the present investi-
gation, an attempt was made to obtain data from applications equal to
and smaller than the lime requirement of the soil, in order to more nearly
approximate field conditions.
EXPERIMENTAL STUDIES
All the soils used were of the Dunkirk silt loam series, and were
obtained from two stations on the Cornell University farm. In addition,
work was undertaken with samples from the lime plots on Caldwell Field.
All the soils analyzed approximately the same mechanically.
TABLE I. MercHANICAL ANALYSIS OF DUNKIRK SILT LOAM SOILS
Soil Tech. Plats
and Station I Station I]
"Potal sands. ct cts oie ete oe Sena eee eae ee 13.9% 9.8%
Srp ee ES A Oe. a a ee ee eS 67.4 T1z9
Glaye cons Ses. c FES Se eee eee. 18.6 18.3
Unpublished results of bulk analyses give:
TABLE II. Butk ANALYSES OF DUNKIRK SILT LOAM SoIL
(From 9 samples of Tompkins County soil)
Surface % Subsoil %
CS (Greanietcarbom)i oes. ee a. eee eee ee 1.670 0.440
COger ten BY sy OR ES A ane ee corer: trace 0.260
| G1 0 en eA aE ane ER Ae CPR EM ee, NICE CS fy see TLS 1.740 2) lO)
Oi 0 ae Piet irae ei ng Pah ts EE ME! eg SC a nS As 0.430 0.830
MigOsk 262 5-2 aaa 0 a ne reed ee 0.450 0.690
Nag O isan. sek a eed Se is ne een es ee as 1.090 1.280
I part sis cs ena” BE lai Sie tS oy ab oy a 0.186 0.082
PsOs so she he, Re er ek ee a ee 0.123 0.126
In sampling the soil in the field, care was taken to get well down
below the sod line in order that organic matter be excluded as far as
possible. The material was brought in to the laboratory, put through a
coarse sieve, and well mixed. The soil had an acidity of 3000 pounds of
calcium oxide per acre,-as determined by the Veitsch method. All the
limes used were 200 mesh, and pots were set up with calcium hydrate,
limestone, precipitated calcium carbonate, gypsum, and precipitated cal-
cium sulfate. In addition, studies were conducted with precipitated
basic magnesium carbonate, and sodium carbonate. The limes were added
in molecularly equivalent amounts, and proper corrections were made
THE PHYSICAL ACTION OF LIME ON CLAY SOILS 15
for magnesium in the limestone (it was nearly pure), and for water of
hydration. Applications were made in the equivalents of one-half,
one and one-half, four and one-half, and ten tons of calcium oxide per
acre, taking two and one-half million pounds as the weight of an acre—
eight inches of soil. The one and one-half ton treatment exactly corre-
sponded with the lime requirement of the soil. Into each pot was
weighed the equivalent of 253 grams of oven soil. The container was
given a prolonged tamping, two thicknesses of cotton gauze added, and
finally a mulch of washed quartz sand placed on top to a thickness of one
centimeter. Aerated distilled water was added to bring the pots up to
24 or 28 per cent water content, at which they were maintained for the
remainder of the experiment. (Note: all references to water content
in this treatise are on an oven dry basis.) A portion of the series were
set up in triplicate; the rest in quadruplicate. The duration of the
experiments was 45, 100, and 225 days. On the expiration of the required
time, the mulches were removed, the soil sieved (20 mesh), dried down
to 7-10 per cent, and bottled. The soils were never allowed to reach air
dryness.
In the exposition on procedures for estimating internal surface,
eighteen methods were examined as to their respective merits. We found
that the great majority are for one reason or the other inaccurate. Six
of them were used in the present investigation, namely,—
1. Penetration.
2. Expansion.
3. Total retentive power.
4. Dye adsorption.
5. Hygro-interstitial water.
6. Oxidative power.
EFFECT OF SALTS ON PENETRATION
The apparatus used for the measurement of penetrability was the
Atterberg apparatus as improved by Prof. H. O. Buckman of Cornell
University. The feature worthy of particular attention is the device for
controlling the distance that the pin enters the soil. With the pin point
flush with the surface of the soil, the mercury well may be set so that the
metal point on top just makes contact with a similar point on the piston.
The distance from this position to the surface of the mercury is constant,
and represents the distance which the pin penetrates. Water is used to
give the gradually increasing force to the head of the piston. On receiy-
ing the signal from the sounder, the water is stopped, and the weight in
the container is determined. This value represents the penetrability of
the particular soil concerned.
A series which had run for 100 days was eed for the penetration
determinations, and in order to avoid the results incidental to air drying,
16 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
readings were made when the moisture percentage of the soil was between
14-15 per cent. Five readings were attempted in each pot, and since the
series was in triplicate, fifteen readings per treatment were obtained.
TABLE III. PENETRATION IN GRAMS OF SorLs LIMED FoR 100 Days
(Each figure is the average of 15 determinations)
| Cheeks Lime-
(no treat.) | Ca(OH )e stone pCaCQ3 | Gypsum NasCO3
BN twe,« hye eee ecg eee 1148 TRF See ieee wea Pa Pe SANS if 4137
Pe ie Mes Eat cde iy ae 115 BO RIG Buc wena 1E9 339
‘elo: Fs ee aie od, ee Ae 709 1045 2374 1912 4499
P.E Res case tees 196 37 152 182 451
444 T (87 392 904 2294 1832 4678
126 18) 83 29 Pat NG L332 534
UES Mea ee etl paral aan es 2; 306 GOR aaa ee ee eee War BY
IP Renate Lit ba ae 15 Se ees A een ee eee le 387
While the probable error in some cases is rather high, nevertheless,
we may draw the general conclusion that calcium hydrate decreases sur-
face penetrability more than any of the other salts tried. One thing
worthy of note is that calcium carbonate seemed to increase the value
when used in small amounts. Unfortunately the question of crust forma-
tion enters in, and tends to confuse the results. There is virtually no
hardening on the surface of the untreated soil, while those to which has
been added a half a ton of lime per acre may form quite a tough crust,
as in the case of the gypsum treatments. What our results indicate,
then, is that calcium hydrate causes the formation of a less impervious
crust than any other lime. If the penetration method is to be used as a
measure of the internal and not the surface condition, the crust must be
removed.
Penetration studies on the interior portion of the soil were attempted.
3rass pins of various shapes and sizes were advanced into the soil with
the ratchet of the micrometer used in connection with the expansion
studies. The distance that the ratchet forced the pin into the soil was
read directly on the micrometer scale. (The crust had been removed.)
The results failed to show significant differences between the different
salt treatments. We may therefore conclude that the influence of salt
treatment is primarily on crust formation, in so far as the penetration
method is a proper criterion. It cannot be used for very sensitive meas-
urements, because it is subject to a number of uncontrolled factors.
EXPANSION STUDIES
It was evident from the preliminary discussion that we would expect
flocculation and expansion to go hand in hand. Furthermore, it seemed
that expansion studies should be conducted at a constant moisture con-
THE PHYSICAL ACTION OF LIME ON CLAY SOILS le
tent. In order to observe expansions under these conditions, a series
which was running for 100 days was selected for special experimenta-
tion. Measurements were made according to a method suggested by
Professor J. A. Bizzell of Cornell University. A ratchet micrometer was
fastened to a standard so that the spindle head could play on a brass
pin which projected three-fourths of an inch above the surface of the
soil. The pin passed perpendicularly through the middle of a small brass
plate, the latter resting on the soil surface. The pin was further steadied
by a projection passing down into the soil. A reading was made by
lowering the micrometer spindle gently in to the pin, until there was
a constant “pull” on the slip of thin paper inserted between pin and
spindle. This method is accurate to the hundredth of a millimeter. .
In setting up the experiment, pins were placed on the one-half, one
and one-half, and ten ton treatments only. The initial reading was
made three hours after the pots had been brought up to weight. During
the course of the experiment readings were taken from time to time;
in each case, however, 24 hours after watering, inasmuch as approxi-
mately 24 hours were required to evaporate the water from the quartz
mulch.
EFrect oF TIME AND SALTS ON SoIL EXPANSIONS
(Each figure in the following data is the average of quadruplicate determinations.
The values all have a negative sign, i. e., there was contraction in every Case.
Readings are in mm.)
Treatment 14 Days | 25 Days | 35 Days | 45 Days | 90 Days
NO MERE ALMNON tivis, ras hovis ele << ce hertuue wane 176 2.14 2.44 Sait SBS
Pee SP ere a tre cht mR ea tec 18 PAT 25 .26 34
Ca(OH).
LeU ee ae pe eee eae co eee 1.49 1.85 2.19 2.76 Sew
20 .09 07 09 O08
ile Lt Ao a OD eR ee A ee 88 tse 1.59 BVT 2.60
12 subg’ Di 14 18
TAL Ua gi ie te RS Se hence 34 .58 .79 22 1.39
03 .02 .03 02 03
Limestone
LL UN St ae le ee a Re 1.20 1.56 L7G Pes H| 2.68
18 .18 a 5 18 32
Pe ore lee Peart wipers Mage Ph se Ya epte Bek te 1.61 1.95 2.35 2.86 Baral
13 wis wll! 15 15
Meena ee en Ee. reg ere ca. ks 5D 70 1.03 1.49 172
O8 10 .09 10 13
p. CaCOs
es "Milano a oped ae RGA aera a a .98 EO) 1.84 2.44 2.96
TG} 23'- ari 30 49
TALS) UC ee eee Sens eet PO naene ye ear gees ine Po 1.76 Pepe 3 Bells:
ROMS As eitaseenc cs Seale - hatte ane ehe .90 1.46 174 2a t 3.03
04 08 04 04 07
p CaSO 4
USNS Oa gira oA yg Were eae eal Rr ie vhs 1.03 2 1.67 1.97
12 14 +b 12 18
18 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
EFFECT OF TIME AND SALTS ON Sort ExPpANSIoNS—Continued
Treatment 14 Days|25 Days|35 Days|45 Days|90 Days
1g eee ed eee ae if 3 1.55 1.89 2.20
11 15 Bl ic3) 06 09
1 0 iad ba arama Comer cbt A eS be ye oss 77 1.06 1222 ear: 1.87
04 04 04 06 08
p. MgCOs; (basic)
Dg Esc Seb og eA ee 92 1.49 li. SOs ye eee 2.95
08 15 TG EL eae 18
etal MA ee rag Peg ERR Cs BAR te or 07 ios Zena 2 AG vot See 3.47
19 17 ASS clea 25
TOS acs aie oes ee eles ee re leer 2205, PHEOK igre ithe oe eM os: One
18 .29 225: at eee 44
NaeCO;
BT of Pleas, cee ace REE Oe ee oe eee ee .89 1.19
ip 25
Bg Te os age esas ee Oe ies Ae oe | .89 2.02
44 51
LOT ics nee yg htc sR OAS ae ee eae a eee ee 3.24 3.83
.60 67
We see from the above data that the contraction with the calcium
hydrate treatments is decidely less than with the limestone. There is not
much difference between the limestone and precipitated carbonate data
when small applications were employed. The limestone seemed to be
superior to the precipitated carbonate, however, when large applications
were used. There was less contraction with the soils to which precipitated
calcium sulfate had been added than with any of the others. In this
connection it should be noted that a smaller contraction than the check
does not necessarily imply a greater expansion. Anything causing an
abnormal solidification of the soil mass may be wrongly interpreted as
an expansion. In the case of the sodium carbonate pots we probably
have this action. The precipitated magnesium carbonate seems to exert
no particularly striking effect.
EFFECT OF LIMING ON THE TOTAL RETENTIVE POWER
The determinations were carried out in the following manner: A soil
of known moisture content was poured into a weighed Hilgard cup, in the
bottom of which was a filter paper. After tamping a definite number of
times the top portion was struck off with a straight-edge, and then the
cup and soil weighed. Knowing the moisture content of the soil, the
dry weight equivalent in the cup could be easily determined. The cup
was then set into water in a thermostat so that there would just be
capillary contact. After the soils had become thoroughly saturated (a
matter of several hours), the cups were set aside to drain, after which
they were wiped dry, and weighed. 2 stone p. CaCO; | Gypsum
Ue MRE SA) br cas SM oie eo rec pe pin nh 183 210 168 114
EERE Sere nn. paises se en ees 162 151 163 95
RMN Pets te ha \Fsint |. .c tanea! Soo RL 117 138 140 106
U2) TT 5 2 SE ea Sea yeni set Oe ee Pee 57 139 133 82
Each figure in the preceding tables is the average of triplicate deter-
minations. While calcium hydrate decreases adsorption the most when
10 ton treatments are used, precipitated carbonate and gypsum are more
efficient with slight applications.
Studies were conducted with safranine in order to observe the effect
of salts in the adsorptive power of the organic matter. Preliminary
experiments indicated that adsorptions could not be conducted with
safranine in the presence of sodium and magnesium carbonates. The
results are as follows:
ApSorRPTION OF SAFRANINE BY SOILS TREATED FOR 45 DAYS
Lime-
Treatment Check Ca(OH)2 stone p. CaCO; | Gypsum
COE Bee rcs ee car eae 52 52 62 60
IRM ero gt SA. yihici A hie es 51 44 45 42 62
ADSORPTION OF SAFRANINE BY SOILS TREATED FOR 225 DAYS
Lime-
Treatment Check Ca(OH)2 stone p. CaCO; | Gypsum
bere nee Se re oe ek crab xy 47 60 61 S4ae
i) Ei bho Mee ey Dan eae 51 42 61 61 34
22 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
With the soils treated for 45 days, liming seemed to decrease the
adsorptive power when applied in excessive amounts. The same applies
to calcium hydrate and gypsum for the 225 day treatments. On the
other hand, limestone and precipitated carbonate increased the adsorp-
tive power slightly. It may be that the analogy of internal surface does
not apply to organic matter, and that the influence of salts on the
adsorptive power is primarily chemical rather than physical.
Adsorption experiments were conducted with diamine sky blue and
with diamine violet, both of which are specific for hydrous aluminum
oxide. Unfortunately neither is stable in the presence of very much elec-
trolyte, and experiments could be conducted with soils which had been
limed not to exceed a ton and a half per acre. The tests failed to show
any differences in adsorptive power. In other words, limes do not
precipitate hydrous aluminum oxide when added in the equivalent of a
ton and a half per acre. The writer has found eosin to be much better
than either of the above dyes for the study of the adsorptive power of
aluminum. Its adsorptive equilibrium is not influenced by salts present
in solution in the equivalent of 10 tons per acre.
ADSORPTION OF HKOSIN BY SOILS TREATED FoR 45 Days
Treatment | Ca(OH)» IDEs p. CaCO3 | Gypsum | NaeCO3 Checks
496 Tm) el boy Salt eas 51 45 5A 54
Hyde aes op: ci eae 40 41 48
ADSORPTION OF EOSIN BY SOILS TREATED FOR 225 Days
Treatment | Ca(OH)» L. 8: p. CaCOz | Gypsum | NasCO; Checks
Uo coe eae: 26 25 24 25 22 30
Bord hed ee 23
It seems from the above data that all limes precipitate aluminum to
some degree. Probably gypsum has a stronger action in this respect
than any of the others.
Taking the adsorption data as a whole, it appears that the primary
effect of liming is the precipitation of the silicic acid, as indicated by the
methylene blue tests. The influence of lime is noticeable, even when
added in very small amounts. Indirectly, we also get a precipitation
of the aluminum, and perhaps the organic matter. Any statement as to
the effect on the colloidal iron will have to be deferred until a suitable
dye is obtained.
THE PHYSICAL ACTION OF LIME ON CLAY SOILS 23
HYGRO-INTERSTITIAL MOISTURE STUDIES
In view of the unsatisfactory results obtained by the Rodewald-Mit-
scherlich method, it seemed desirable to revert to the type of procedure
used in the beginning. The writer has been fortunate in obtaining a
method which is free from errors due to condensation, and is at the same
time exceedingly accurate. Preliminary work with this method indicates
that liming seems to have no significant effect on hygro-interstitial mois-
ture in amounts equivalent to the lime requirements of the soil. Exces-
sive applications decrease the value.
OXIDATION STUDIES.
The work was conducted as follows: The equivalents of four grams of
soil were weighed into 8-oz. bottles, and 50 cc. of phenolphthalein solu-
tion added. After oxidation had progressed satisfactorily, the solutions
were cleared of humus and suspended matter with hot alum solution, an
aliquot made alkaline with ammonia, and read against a standard. The
results are as follows: (Each figure is the average of three determina-
tions. The probable error is approximately a plus or minus two).
OXIDATION OF PHENOLPHTHALEIN BY SOILS TREATED FOR 100 Days
Treatment Cheek|Ca(OH):| L. S. |p.CaCOs|p. CaSO4} NazCOs |». MgCO3
| aS ae eee | «oO o7 87 109 76 95 82
Daa eS eras 88 72 98 58 95 chal
Ee Sen (naa ie 104 63 wi 50 86 47
OXIDATION OF PHENOLPHTHALEIN BY SOILS TREATED FOR 225 DAYS
Treatment Checks Ca(OH). L. 8. p. CaCQs3 | Gypsum NasCQ3
ol RARE 68) ae ae ee 71 62 63 46 61
oy 76 82 72 72 45 Do
PME te enh Sin aks 27 « 88 75 73 57 D2
The data for the soil run 225 days goes just about as we would like it
to go. We get the greater oxidation in soils in which we would expect
the greater internal surface, and we obtain a decrease in oxidation with
increasing applications of lime. The results for the soils run 100 days
are not quite so satisfactory. It may be that in certain cases an exchange
of bases results in the release of substances which catalyze the reaction.
24 THE PHYSICAL ACTION OF LIME ON CLAY SOILS
STUDIES WITH PLAT SOILS
An attempt was made to determine whether differences could be
observed between soils from limed and unlimed plats, using our methods
for estimating internal surface. Accurate samples of the surface and
subsoil were taken from plats 7007, 7008, 7207, 7208, 3611, 3612, 3613,
and 3614. The seven thousand plats received a moderate application of
CaO in the summer of 1915, while the three thousand plats were last
limed in the summer of 1910. The soils were examined according to the
total retentive power, dye adsorption, and oxidation methods. None of
the results were consistent with regard to the limed and unlimed plats,—
with one exception,—the oxidation results for the seven thousand plats.
OXIDATION OF PHENOLPHTHALEIN BY LIME PLAT SOILS
Soil Description Comparative Figure
TO OW aye ef ne A aa (OIIfail anys Let Mae ys ee ie £9.15
OOS ET Fee eae ee See ee Fee TED AOC et he Neen eee 63.0
CTU Ok ae cees PMat eat Seated gh ens Winlimncdh agen eer i 93.0
20 Se isa. 2k ate Oe hog eee eee We Nene 1 Ey 276 AN eileen Ree a Nth a Be Nt 106.0
The above figures are averages of duplicate determinations, and the
probable error is less than one. We may conclude that several years time
are usually sufficient to virtually obliterate all physical differences
between limed and unlimed soils.
DISCUSSION
Six methods have been employed in the present investigation. We
have observed that the total retentive power and penetration procedures
are not particularly valuable because of the high probable error involved.
The oxidation method has not been used sufficiently as a means of esti-
mating internal surface to permit its appraisement at the present time.
Expansion, hygro-interstitial moisture, and dye adsorption seem to be
accurate and valuable methods. It appears to the writer that the dye
method has the brightest future of all, for it permits the determination
of the effect of substances in specific materials.
CONCLUSIONS
1. The penetration method is not a suitable procedure for estimating
internal surface.
2. Small contraction exhibited by a salt treated soil does not neces-
sarily imply large expansion.
3. Gypsum treated soils contracted less than any other lime treat-
ment.
nosey
7
THE PHYSICAL ACTION OF LIME ON CLAY SOILS 25
4, Gypsum appears to be an active precipitant of silicic acid and
hydrous aluminum oxide.
5. New methods for the determination of soil expansions and hygro-
interstitial water have been devised.
6. Liming in amounts equivalent to the lime requirement of the soil
has no effect on the hygro-interstitial water.
7. Calcium hydrate is only slightly more valuable as an ameliorating
agent than limestone.
8. The physical effect of precipitated magnesium carbonate on the
soil is nil.
9. The dye adsorption method has the greatest possibilities of all
methods for estimating internal surface.
10. The primary effect of liming is on the silicic acid.
BIBLIOGRAPHY
1. Apams, E. A., anpD RosENSTEIN, L.
1914. The Color and Ionization of Crystal Violet.
J. Am. Chem. Soc. 36, 1452.
2. ALBERT, R.
1905. Welche Erfahrungen liegen bis jetzt tiber den Ejinflusz
kiinstlicher Diingung und Bodenbearbeitung im forst-
lichen Groszbetreibe vor? In welcher Weise und nach
welcher Richtung hin sind Versuche hiertiber fernerhin
anzustellen? Zeitschr. f. Forst. und Jagdwesen, 37, 139.
3. Ames, J. W., AND SCHOLLENBERGER, C. J.
1916. Liming and lime requirement of soil. Ohio Expt. Sta.
Bul. 306.
4, Ammon, G.
1879. Untersuchungen tiber das Condensationsvermégen der
Bodenconstituenten fiir Gase.
Forsch. a. d. Gebiete der Agrikultur-Physik, 2, 1-46.
5. ARNtTz, E.
1909. Tonbestimmung im Boden.
Landw. Versuchss., 70, 269.
6. AsHuey, H. E.
1909. The colloidal matter of clay and its measurement. US,
Geol. Survey Bul. 388.
i Asurny, H. Bb.
1913. Technical control of the colloidal matter of clays. Bureau
. of Standards Technologic Paper No. 23.
8. ATTERBERG, A.
1911. Die Plastizitat der Ton.
Internat. Mitt. f. Bodenkunde, 1, 10.
10.
it:
13.
14.
15.
16.
Lf:
eS.
20.
21.
THE PHYSICAL ACTION OF LIME ON CLAY SOILS
ATTERBERG, A.
1912. Die Konsistenz und die Bindigkeit der Béden.
Internat. Mitt. f. Bodenkunde, 2, 149.
ATTERBERG, A.
1914. Die Konsistenz Kurven der Mineralbéden.
Internat. Mitt. f. Bodenkunde, 4, 418.
Bancrort, W. D.
1914. The theory of colloid chemistry.
Jour. phys. chem. 18, 549.
Bancrort, W. D.
1914-15. The Theory of Dyeing.
Jour. phys. chem. 18, 1, 118, and 385. 19, 50, and 145.
Bancrort, W. D.
1915. Hydrous ferric oxide.
Jour. phys. chem. 19, 232.
Barus, C.
1886. Uber das Absetzen von feinen festen Massenteilchen in
Fliissigkeiten.
Ann. Phys. U. Chem. 12, 563.
BEAUMONT, A. B.
1918. The Reversibility of Soil Colloids,
Thesis, Cornell University.
BecHHOLp, H.
1912. Die Kolloide in Biologie und Medizin. Dresden.
BEMMELEN, J. M. van.
1878-79. Das Absorptionsvermégen der Ackererde.
Landw. Versuchss. 22, 135, 265.
BEMMELEN, J. M. VAN.
1881. Die Verbindungen einiger fester Dioxydhydrate mit
Saéuren, Salzen, und Alkalien.
Jour. prakt. Chem., (Ser. 2) 23, 388.
2MMELEN, J. M. VAN.
—
ww
—
1888. Die Absorptionsverbindungen und das Absorptionsver-
mogen der Ackererde.
Landw. Versuchss. 35, 69.
BEMMELEN, J. M. VAN.
1904. Beitrige zur Kenntnis der Verwitterungsprodukte der
Silikate in Ton. vulkanischen und Lateritbéden.
Zeit. f. anorg. Chemie, 42, 265.
BEMMELEN, J. M. VAN.
1909. Die Verwitterung von Tonbéden.
Zeit. f. anorg. Chem. 62, 221.
"
te
bo
24,
25.
i)
a |
28.
30.
31.
32.
33.
THE PHYSICAL ACTION OF LIME ON CLAY SOILS 27
. BEMMELEN, J. M. van.
1910. Die verschiedenen Arten der Verwitterung der Silikat-
gesteine in der Erdrinde.
Zeit. f. anorg. Chemie, 66, 322.
BEMMELEN, J. M. von.
1910. Die Absorption: gesammelte Abhandlung tiber Kolloide
und Absorption; mit unterstiitzung des Verfassers neu
herausgegeben von W. Ostwald. Dresden.
BuancK, E.
1909. Der Einfluss des Kalkes auf die Wasserbewegungen im
Boden. Landw. Jahrb. 38, 715.
BLANcE, E.
1909. Ein Beitrag zur Kenntnis der Wirkung kiinstlicher
Diinger auf die Durchlissigkeit des Bodens fiir Wasser.
Landw. Jahrb. 38, 863.
Buanck, E., unD Dosresct, J. M.
1914. Weitere Beitraige zur Beschaffenheit rotgefarbter Boden-
arten. Landw. Versuchss. 84, 427.
BopLANDER, G.
1893. Versuche tiber Suspensionen.
sahrb. t.. Min. Ti, 147.
BreuM, H.
1913. Uber die Fortschritte und Aussichten der jiingeren Agri-
kulturchemie (speziell der Bodenchemie) seit Anwendung
der neueren Ergebnisse der physikalischen Chemie, be-
sonders der Kolloidchemie. Kolloid Zeit. 13, 19.
Brices, L. J.. AnD McLang, J. W.
1907. The moisture equivalents of soils.
U. S. Bureau of Soils, Bul. 45.
Brown, G. H., anp Monrcomnry, EH. T.
1913. Dehydration of Clays.
U. S. Bureau of Standards, Technologic Paper No. 21.
Buutrr, A.
1892. Untersuchungen tiber Sickerwassermengen. Mitt. d.
Schweiz. Zentralanstalt fiir forstl. Versuchswesen 1,
291. Cited from Jahresb. Agr.-Chem. neue. Folge, 15,
(1892), 97. :
Cameron, F. K.
1915. Soil colloids and the soil solution.
Jour. phys. chem. 19, 1.
CAMERON, F. K., anp GALLAGHER, F. E.
1908. Moisture content and physical condition of soils.
U. S. Bureau of Soils, Bul. 50.
35.
36.
of.
39.
40).
41.
43.
44,
THE PHYSICAL ACTION OF LIME ON CLAY SOILS
Cornu, F.
1909. Die Anwendung der histologischen Methodik zur mikro-
skopischen Bestimmung von Kolloiden, namentlich in der
Bodenkunde. Koll. Zeit. 4, 304.
CzERMAK, W.
1912. Ein Beitrag zur Erkenntnis der Veranderungen der sog.
physikalischen Bodeneigenschaften durch Frost, Hitze,
und die Beigabe einiger Salze. Landw. Versuchss. 76,
73.
Davis, R. O. E.
1912. The effect of soluble salts on the physical properties of
soils. U.S. Bureau of Soils, Bul. 82.
Ditruer, E.
1909. Ueber die Einwirkung organischer Farbstoffe auf Miner-
algele. Koll. Zeit. 5, 93.
DospENEcK, A. F. von.
1892. I. Physik des Bodens. LXV. Untersuchungen tiber das
Adsorptionsvermogen und die Hygroskopizitat der
Bodenkonstituenten. Forsch. a. d. Gebiete d. Agrikultur-
Physik, 15, 168.
EBERMEYER, E.
1890. Untersuchungen tiber die Sickerwassermengen in verschi-
edenen Bodenarten. Forsch. a. d. Geb. d. Agrikultur-
Physik. 13, I.
EHRENBERG, P.
1908. Theoretische Betrachtungen iiber die Beeinflussung
einiger der sogenannten physikalischen Bodeneigenschaf-
ten. Mitt. d. Landw. Inst. d. Univer. Breslau, 4, 445.
EHRENBERG, P.
1915. Die Bodenkolloide. Verlag yon T. Steinkopf, Dresden
und Leipzig.
EHRENBERGER, P., UND Pick, H.
1911. Beitrag zur Physikalischen Bodenuntersuchungen.
Zeit. f. Forst. und Jagdwesen, 48, 35.
ENGELS, O.
1914. Der Einfluss von Kalk in Form von Atzkalk und kohlen-
saurem Kalk auf die physikalische Beschaffenheit ver-
schiedener Bodenarten. Landw. Versuchss., 83, 409.
Fickenbry, E. unp Toiens, B.
1906. Notiz tiber Schutzwirkung von Kolloiden auf Tonsuspen-
Sionen und natiirlische Tonbéden. Jour. f. Landw. 54,
343,
THE PHYSICAL ACTION OF LIME ON CLAY SOILS 29
Fiprin, E. O.
1910. Some causes of soil granulation. Proc. Am. Soc. Agron.
2, 106.
Fraps, G. S.
1914. Ammonia soluble inorganic soil colloids.
Tex. Sta. Bul. 165, 3.
Frear, W.
1900. The agricultural use of lime.
Commonwealth of Pennsylvania, Bul. 61,
Frear, W.
1915. Sour soils and liming.
Pennsylvania Dept. or Agr., Bul. 61.
Free, E. E.
1900. The phenomenon of fiocculation and deflocculation.
Jour. Franklin Inst. 169, 421.
FREUNDLICH, H.
1909. Kapillarchemie; eine Darstellung der Chemie der Kolloide
. und verwandter Gebiete. Leipzig.
Gans; R.
1915-14. Uber die chemische oder physikalische Natur der Kol-
loiden Tonerdesilikate. Zentralb. f. Min. u. Geol. 1918,
699, 728. 1914, 273, 299, und 365.
Geproits, K. K.
1912. _ (Russian title). Colloid chemistry in the study of soils.
Zhur. Opytn. Agron. (Russ. Jour. Expt. Landw.), 18,
363.
Gite, P. L.
1911. Relation of calcareous soils to pineapple chlorosis. Porto
Rico Agr. Expt. Sta., Bull. 11, 45.
Gite, P. L., anp Carrero, J. O.
1914. Aecieiation of colloidal iron by rice.
U. 8. Dept. Agr., Jour. Agr. Research, 3, 205.
GIvEN, G.
1915. Kolloide Eigenschaften des Tons und ihre Beeinflussung
durch Kalksalze. Inaug. Dissert. Gottingen. Cited
from Koll. Zeit., 81, 29. «
Gross, E.
1903. Uber den Einfluss der kiinstlichen Diingemittel auf das
Verhalten des Wassers im Boden. Zeit. f. d. Landw.
Versuchswesen in Osterreich, 6, 80.
HABERLANDT, H.
1878. Uber die Koharescenz Verhaltnisse verchiedener Boden-
arten. Forsch. a. d. Geb. d. Agrikultur-Physik, 1, 148.
30
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
69.
70.
THE PHYSICAL ACTION OF LIME ON CLAY SOILS
Hat, A. D.
1908. The Soil. London.
Harpy, W. B.
1899. A preliminary investigation of the conditions which de-
termine the stability of irreversible hydrosols. Proc. Roy.
Soc. London. 66, 110.
HeEwen, E.
1883. Kondensation des Wasserdampfes durch lufttrockenen
Boden. Denkschrift zur Feier des 25 jahriger Bestehens .
der agrikulturchemischen Versuchsstation Pommritz.
Hannover. Forschungen a. b. Gebiete d. Agrikultur-
Physik, 7, 324.
HiLearD, E. H.
1911. Soils. New York. p. 209.
HoutuEeMaAnny, A. F.
1892. Uber die Bekalkung von steifen Kleybéden.
Landw. Versuchss. 41, 37.
HUNDESHAGEN, F.
1908. Ueber die Anwendung organischer Farbstoffe zur diag-
nostischen Farbung mineralischer Substrate.
Zeit. f. angew. Chem. 21, 2405.
ImMeEnporrr, H.
1918. Die an hydratischer Kieselsiure reichen Kalke als
Diingemittel. Landw. Versuchss. 79-80, 891.
Kerppuer, G., UND SPANGENBERG, A.
1907. Notiz tiber die Schutzwirkung von Kolloiden auf Tonsus-
pensionen. Jour. Landw. 55, 299.
Krinnison, C. S.
1915. A study of the Atterberg plasticity method. U.S. Bureau
of Standards. Technologic Paper No. 46.
Konic, J., HASENBAUMER, J.. UND Hassuer, C.
1911. Bestimmung der Kolloide im Ackerboden.
Ladw. Versuchss. 75, 377.
Krawkow, 8.
1900. Uber die Prozesse der Bewegung des Wassers und der
Salzlésungen im*Boden. Jour. f. Landw. 48, 209.
Lacroix, A.
1914. Les produits d’alteration des roches silicatées alumi-
neuses, et en particulier les latérites de Madagascar.
Compt. Rend. Acad. Sci. (Paris), 159, 617.
LEHMANN, O.
1894. Ueber Sedimentation und Farbstoffabsorption.
Zeit. Phys. Chem. 14, 157.
a,
72.
73.
74.
75.
77.
78.
80.
82.
THE PHYSICAL ACTION OF LIME ON CLAY SOILS 31
MacIntire, W. H.
1916. Factors influencing the 1s and magnesia requirements
of soils. Tenn. Agr. Expt. Sta. Bul. 115.
MacIntirg, W. H.
1916. The carbonation of burnt lime in soils. Thesis, Cornell
University.
MacIniire, W. H., Wiis, L. G., anp Houpine, W. A.
1914. The Non-Existence of Magnesium Carbonate in Humid
Soils. Tenn. Agr. Expt. Sta. Bul. 107, 151.
MacIntire, W. H., and WILLIS, L. G.
1914. Comparison of silicates and carbonates as sources of lime
and magnesia for plants. Jour. Indus. and Engin. Chem.
6, 1005.
MascHHaupPt, J. G.
1914. Einige Bemerkungen zu Prof. Dr. Rohlands: Die Wir-
kung der Hydroxylionen auf Tone und tonige Béden bei
der Mergelung. Landw. Versuchss. 83, 467.
MAsonl!, G.
1912. Intorno all’azione flocculante di alcuni sali solubili sulle
materie argillose del terreno. Staz. Sper. Agri. Ital., 45,
113.
MaAusBereG, A.
1913. Wie beeinflusst die Diingung die Beschaffenheit des
Bodens und seine Hignung fiir bestimmte Kulturgew-
Achse? Landw. Jahrb. 45, 51.
Mayer, A.
1879. Ueber die Einwirkung von Salzlésungen auf die Abset-
zungsverhiltnisse thoniger Erden. Forsch. a. d. Geb. 4.
Agrikultur-Physik, 2, 251.
McGeorce, W. T.
1915. Soil Colloids.
Hawaii Agr. Expt. Sta. Report 1915, 36.
Meyer, A.
1874. Uber das Verhalten erdartiger Gemische gegen das
Wasser. Landw. Jahrb. 3, 794.
Mirscuervuicu, E. A.
1898. Beurteilung der physikalischen Eigenschaften des Acker-
bodens mit Hilfe seiner Benetzungswarme. Inaug. Dis-
sert. Kiel.
MITSCHERLICH, E. A.
1905. Die Bodenkunde. Berlin.
84.
87.
Or
93.
94.
96.
97.
THE PHYSICAL ACTION OF LIME ON CLAY SOILS
Norn, OF.
1913-14. Effect of fertilizers on soil structure as indicated by the
draft of a plow. Penn. Agr. Expt. Sta. Annual Report,
p. 36.
Ornyng, T.
1914. Kritische Bemerkungen zur Frage der Bestimmung des
Adsorptionsvermégens des Bodens. Koll. Zeit 15, 105.
OstwaLp, W.
1910. Grundriss der Kolloidchemie. Dresden.
Pappapa, N.
1911. Uber die Koagulation des Eisenhydroxyds. Koll. Zeit.
9, 233.
Parker, E. G.
1914. Selective adsorption.
Jour. Ind. Eng. Chem. 6, 831.
PELET-J OLIVET, L.
1910. Die Theorie des Farbeprozesses. Dresden.
PELET-JOLIVET, L.
1909. Ueber die Adsorptionsverbindungen. Koll. Zeit. 5, 85.
Pervert, L. uND ANDERSEN, N.
1908. Ueber den Einflusz von Sauren und Basen auf den
Farbungsvorgang. Koll. Zeit. 2, 225.
Peet, L. uND GRAND, L.
1907. Ueber die Bindung einiger Farbstoffe durch unlésliche
Mineralsubstanzen. Koll. Zeit. 5, 94.
Peet, L. unp GRAND, L.
1907. Ueber den Einflusz von Salzen auf den Farbungsvorgang.
Koll. Zeit. 2, 83.
Picton, H. anp Linpmr, S. E.
1892 & Solution and pseudo-solution.
1895. Jour. Chem. Soc. 61, 148, and 67, 63.
PucHNeEr, H.
1889. Untersuchungen tiber die Kohareszenz der Bodenarten.
Forsch. a. d. Geb. d. Agrikultur-Physik, 12, 195.
PucuHner, H.
1918. Vergleichende Untersuchungen iiber die Kohareszenz
verschiedener Bodenarten. Internat. Mitt. f. Bodenk. 3,
141.
RopEWALD, H., uND MirscHERLICH, E. A.
1903. Die Bestimmung der Hygroskopizitiat.
Landw. Versuchss. 59, 433.
Rocers, A. F.
1917.