Group Title: Bulletin University of Florida. Agricultural Experiment Station
Title: Soil studies
Full Citation
Permanent Link:
 Material Information
Title: Soil studies
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Alternate Title: Acid soils
Physical Description: p. 43-69 : ill. ; 23 cm.
Language: English
Creator: Blair, A. W ( Augustine Wilberforce ), b. 1866
Macy, E. J
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1908
Copyright Date: 1908
Subject: Acid soils -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Includes bibliographical references.
Statement of Responsibility: by A.W. Blair and E.J. Macy.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00026435
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - AEN2265
oclc - 18159692
alephbibnum - 000921797

Full Text


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida

BULLETIN NO. 93. MAY, 1908.


Agricultural Experiment Station.


A. W. BLAIR and E. J. MACY.

The bulletins of this Station will be sent free to any address in
Florida upon application to the Director of the Experiment Station,
Gainesville, Fla.

Record Co., St. Augustine


Introduction ................................................... 45
General Remarks on Soils-
How Soils are Formed.......................................... 45
Origin of Florida Soils............................. ...... .. ... 46
Florida Soils Deficient in Bases................................... 47
Causes of Acid Soils-
Decomposition of Organic Matter ................................ 48
Action of Soil Bacteria............................................ 49
Breaking-up of Mineral Fertilizers ........................................... 49
Fermentation of Green Materials................................ 50
Effects of Acid Soils-
Upon the Plant. .............................. ................ 50
Upon the Soil Bacteria.......................................... 50
Upon the Mineral Constituents........ ........ .................. 51
Other Effects ................ .................................. 52
Correctives for Acid Soils........................................... 52
Depths to Which Acids are Neutralized by Lime .................... 55
Table I .................... ............................. 56
Explanation of Table I-
Method of Collecting Samples...................................... 59
Method of Analysis........ .................................. 59
Method of Reporting Acidity..................................... 59
Discussion of Results .............................................. 60
Experiments in Neutralizing Acidity-
Wire Basket Method, Using Lime................................. 63
Wire Basket Method, Using Finely-Ground Limestone............... 64
Summary ............... .......................... .............. 68




A preliminary examination, made some months ago, led to
the belief that Florida soils are more generally acid in character
than has heretofore been suspected. The work herewith
reported was therefore undertaken with the purpose of finding
out to what extent this view was correct, and in the hope that-
light might be thrown upon some of the problems that now
confront the agricultural and horticultural interests of the State.
It is not claimed that this bulletin completes the account of
the subject; for indeed only a commencement of the work has
as yet been made. Our knowledge of the whole matter of acid
soils is still very limited, and further investigation may perhaps
materially change the views of those now working along this
The origin and nature of Florida soils have a direct bearing
upon the causes of their acidity; so that it seems best to
recount briefly the origin of soils in general, and of Florida
soils in particular, before approaching the subject of their
1. How SOILS ARE FORMED.-Practically all soils result
from disintegrating rocks (muck and peat soils may perhaps
be excepted). While the processes of disintegration are ,:,ing
on, vegetable matter is gradually accumulating in the decom-
posed materials, and as a final result there is formed the soil
which is so familiar to us all.
Among the physical agencies which combine to effect the
decomposition of the rocks may be mentioned heat and cold,
water and wind, as well as the action of plants and animals.
Chemical changes are also constantly taking place which aid

46 Florida l.],'ic'lilniial Experiment,Station.

very materially in breaking up the rocks. The oxidation of
iron pyrites and the solution of liuiet_,ine by carbonated waters
are examples of these.
If, then, soil results from disintegrated rocks, it must partake
of the nature of the underlying rock, unless some outside
aecnci---LIuch as moving ice-has disturbed the surface since
the decomposition took place. However, on account of the long
period during which the soil has been su1bjected- to leaching, it
will have lost much of some of the mineral compounds that
existed in the parent rock.
It is apparent, then, that all the mineral elements that enter
into a plant's composition must have come originally from the
rocks. When the plant or animal ceases to exist as such and
decays, then these elements are returned to the earth to be again
taken up probably by other plants, or they may dissolve in the
ground water and be carried out into the sea, perhaps ; to be
taken up even there by plants or animals.
2. ORIGIN OP FLORIDA SoILS.-Like other soils, Florida
soils had their origin in the decomiporn'itio:i of rocks; but they
dil'fer from many other soils in that the rocks did not decompose
where the soil is now found. The deep beds of sand that are
spread out like a mantle upon the limestone basis, furnish
abundant evidence that the greater portion of what is now the
peninsula of Florida was at one time a part of the bed of the
sea. The origin of the sand can only be explained from our
knowledge of rocks and the agencies that effect their decom-
position and transportation. It is known, for example, that
ordinary sand, chemically known as quartz or silica, is an
important constituent of the granite, gneiss, and other hard
rocks which form so much of the backbone of the Appalachian
mountains. With the gradual distinte.gration of these rocks,
this quartz or sand became a part of the soil thus formed; and
as the hills and mountain-sides have been gradually washed
away, some of this sand has slowly made its way into the ocean.
Being heavier than the other materials, the sand would naturally
come to rest in shallow seas along the shores. Later on, at
some period of geologic disturbance, much of what constituted
these shallow seas was raised above the water. During some

Bulletin No. 93. 47

such period, the ridge of limestone and sand that constitutes
Florida was elevated. Through the centuries following this
uplift, natural agencies have been at work changing the surface;
cutting it away in one place to form river channels; filling up
depressions in another; and dissolving the limestone from under-
neath to again form depressions elsewhere. Thus the land
surface has been broken up. and modified, resulting in a soil
which is not always fertile, but nevertheless, when well worked
and fertilized, exceedingly productive.
stance that is opposite in character to an acid. When brought
together each destroys the properties of the other, with the
result that new substances are formed which have properties
differing from both acid and base. Lime and lye may be men-
tioned as familiar examples of bases, and vinegar and oil of
vitriol (sulphuric acid) as common acids. In the rocks which
have been mentioned as being partially composed of quartz
sand, may also be found a number of bases, including lime,
magnesia, potash and soda. Grains of sand are more resistant
to the action of the .elements than most other minerals in the
rocks; hence, through the long processes of decomposition, these
less resistant materials, including many of the bases, have been
dissolved or ground to powder and perhaps carried far out into
the sea, there to remain in solution or to finally settle upon a
muddy bottom. We thus see why it is that the sand is so desti-
tute of the bases needed by plants.
There is then a radical difference between soils that are
formed by the disintegration of rocks in place, such as would be
found on the slopes of the Appalachian mountains, and those
that consist mainly of the sand that has been washed out of such
soils. In the former, disintegration never ceases. As the crops
grow, they remove basic elements from the soil; but natural
agencies are at work to aid in the further decomposition of the
small particles of rock, and thus the process of liberating new
supplies continually goes on. In the case however of soils made
up so largely of sand, further disintegration is exceedingly slow.
As previously stated, sand grains are very resistant, and even
if decomposed, would furnish only traces of the necessary

48 Florida Agricultural Experiment Station.

bases. There may be minute particles of soluble salts or easily
.I..i:piir.c.C,: c.imp...undj adhering to their surfaces, but these
" ill read.lil leach out.
It thus appears that the fertility of such soils can only be
maintained by the ceaseless vigilance of man. If he would have
them productive, he must supply organic matter, a sufficient
amount of some base, and more of the elements needed as plant
food than his crops remove.
Having pointed out that a base is required to neutralize an
acid, and that Florida soils in ,cn-ral are deficient in bases, it
will be clear that, if there are agencies at work producing acids
in our soils-and this is true of practically all cultivated soils--
there will be a tendency for the acid condition to prevail. Our
work, reported in Table I, shows clearly that the acid condition
is quite general in most of the localities thus far studied.
If the soil naturally contains abundance of limestone, the
acidity is, of course, destroyed as r.ipill., as it develops, and so
-.:.-l.'til-'n should here be made of certain sections where bases
are found in considerable abundance; as where the liirst.,n.:
comes to the surface, or where tlierc are phosphate deposits or
soils that are especially rich in phosphates. This applies to
several 1.' cain.ts in Alachua county, where the soil appears to
be abundantly ,iipli-hed with phosphate.
ing down of organic matter in the soil is accompanied by the
f.irmiatio:'i of various organic compounds. The exact nature of
ll!es, compounds is not v..i: kn.:.1 ii, though it is generally agreed
that certain organic acids are among the products. These
organic acids have been variously spoken of as humic, ulmic,
crrnic. and apocrenic. Some writers have questioned the exist-
ence of such acids, but it is very certain that the water extract
of certain soils, especially muck soils, does have a decidedly acid
reaction, even after it has been thoroughly boiled; and since
muck soils are made up almost entircl, of organic matter, it
would s-em safe to assume that acids result from the breaking
down of the *-,r-anlic matter, at least until this has been disproved.

Bulletin No. 93. 49

It is generally believed that these acids-humic compounds,
as they are called-have the power. of attacking and breaking
down insoluble minerals, and of thus liberating plant food.
Experience undoubtedly sustains this belief, inasmuch as many
instances can be cited where the results obtained by the use of
organic matter as a fertilizer are far in excess of what could
be attributed to the plant food contained in the organic matter
2. THE ACTION OF SOIL BACTERIA.-It has been shown that
soil bacteria acting upon. certain portions of the vegetable matter
(carbohydrates) in the soil, 'produce organic acids; hence all
soils well supplied with carbohydrates have a tendency to
become acid as a result of the development of soil microbes.
Among the acids shown to have been formed in this way may
be mentioned acetic, formic, butyric, and lactic.
and others since, have shown that ammonium salts are more or
less completely decomposed in the soil, with the formation of
free acid in the soil solution. It is possible that to this may be
attributed the unsatisfactory results that have been secured, in
some quarters, from the use of sulphate of ammonia on sandy
acid soils.
Keith,1 working in the laboratory of the Bureau of Soils,
has shown that, in general, potassium salts are decomposed in
the same way, free acid being formed. It is not likely, however,
that any injury would result from this cause, except in the case
of frequent and heavy applications. It has been suggested2 that
the injurious effects of acid phosphate on pineapples may be
due to the presence in the phosphate of certain iron anil alum-
inum -ailts ,lhich have an acid reaction. It is certainly true that
a good portion of the pineapple soils of the State are' very
deficient in bases, and it is further true that when phosphoric
acid is supplied as bone meal and slag phosphate, both of which
contain lime, good results are secured.

"Cited by Cameron and Bell, Bulletin No. 30, Bur. of Chem., U. S.
Dep. of Agr.
'BTlletin N.:. 83, Fla Agr. Exp. Sta., Pineapple Fertilizer Experi-
ment-. Mill.-r .Ind Blair

50 F1,:, ida Agricultural Experiment Station.

heavy crop of green material is turned under, fermentation will
set in if the conditions of temperature and moisture are favor-
able, and as a result the soil may become sour. However, if
the soil is well supplied with bases, such as lime, magnesia, etc.,
bacterial development will be hastened and the harmful effects
lessened or removed.
1. UPON THE PLANT.-Experiments have shown that a very
small amount of acid when added to distilled water, or to
nutrient solutions in which plants are .being grown, will kill the
plants: while the same plants will grow for some days in dis-
tilled water to which no acid has been added. Beggarweed
plants placed in distilled water made faintly acid with sulphuric
acid, turned white, shrivelled up, and died without making any
growth whatever; while similar plants, placed in distilled watei
alone, grew for several days, finally dying for want of food.
It would thus appear that an acid solution has a toxic effect
upon the plant itself. Some plants have shown marked powers
of resistance to acid soils, as for example, corn and oats; while
others, as celery, lettuce, cauliflower, beets, cabbage, etc., have
shown a decided improvement when the acid condition has been
partly or wholly corrected; and some, as alfalfa, positive%
refuse to grow in a soil that is decidedly acid.
2. UPON THE SOIL B.ACTERI..-We are gradually learning
that there is a very intimate relation between the fertility of a
soil and the bacterial life of that soil. On this point Chester
says :8 "It is important to know the conditions of the soil which
are most favorable to the rapid development of soil bacteria,
for upon these will depend the abundant elaboration of plant
food. The successful handling of land, therefore, con-
sists largely in satisfying all the conditions demanded by all
classes of soil microbes.
"Among these conditions nothing is so important as to main-
tain a proper reaction of the soil. Acid soils are infertile,

"Annual Rep.ort Del Agr; Exp. Sta., (1899) 11, pp. 83-84.

Bulletin No. 93. 51

because soil bacteria, which are elaborators of plant food, cannot
grow in them. We say that lime, when applied to land, assists
in the decomposition of organic matter in the soil, and in the
elaboration of plant food.
"This is true only indirectly. The lime neutralizes the
acidity of the soil and renders it a more favorable medium for
the development of soil bacteria, which are the true agents for
the decomposition of organic matter and the elaboration of
plant food. Thus the whole question of soil fertility resolves
itself into the problem of looking after the welfare of the soil
These are strong statements, but when we stop to reflect
that a very fertile soil, or a poor soil to which large quantities
of fertilizers have been added, may be so water-logged as to be
almost entirely unproductive, vie must, at least, admit that they
contain much of truth. The excessive amount of water cuts
off, to a large extent, the supply of air which is required by the
bacteria. Muck beds are rich in nitrogen, and often contain
more phosphorus and potassium than is found in the average
soil; though, as a rule, in their native condition, they will not
produce good crops: but make them a fit habitation for soil
bacteria, that is, drain them, and correct the acid condition, and
they become productive. A piece of soil has been "worn out"
by constant and long-continued 'cultivation: incorporate in this
soil a liberal supply of humus, which is one of the requirements
for bacterial development, and you soon notice an increased
capacity for crop production.
Since the conversion of the nitrogen of organic materials
into iiitrate.s-the form in which'plants can use it--i dependent
upon bacteria nitrifyingg bacteria), it is especially important
that the conditions should be made as favorable as possible for
these organisms. It is known, however, that an acid condition
is detrimental to the development of nitrifying bacteria; hence,
the effect of an acid soil in this case is to decrease the supply
of nitrates that should be available for the crop.
--We have seen that the acids in the soil may and do act upon

,':. Florida Agricultural Experiment Station.

the niinral cIii-iittitint. thus bringing into solution plant-food
elenints. They mnay also bring into solution minerals that have
a toxic cfiect iupor:' the plant or tree; as for example, compounds
of iron and alumina.
4. OTHER EJFECTs.-There are doubtless other effects
which are not yet well understood. It is entirely possible thai
certain diseases, the causes of which are not yet known, may be
due, in part at least, to soil acidity. There appears to be good
evidence for the belief that there exists a close relationship
1N_.\, cin. soil acidit' anIl the,lack of ability on the part of certain
plants to secure nutrient materials.
Shall we then refuse to add humus to our soils because it
becomes a source of organic acids? It might be reasoned that
if increasing the organic matter in our soils increases its acidity,
and thus brings about harmful eff-ct.s it is poor' policy to
enc:Lura.-e the formation of humus in the soil; but, as is well
Ikno:in. we inust have the humnls to furnish food for bacteria,
to hli,., lil.eralt plant food that is locked up in the soil, and to
i,!r':'\-e its mechanical c:,nl-liti.-.n. The difficulty must be met
i. ...icr,:...-tin.- the injurious effects of the acids. This is accom-
plished, as we have seen, by neutralizing the acids with a base.

Since lime in some of its forms is the cheapest and, there-
fore, the most economical base, it is in all probability the material
that will be most widely used. It .exists, however, in several
available forms, and there may be some question as' to which
form -h.ii.1.l be selected. For example, it may be had as quick-
lime, hydrated lime, air-slacked lime, and finely ground lime-
stone (the unburned rock, finely ground). It is also contained
in -.Iill-. marl, wood-ashes, lime-kiln ashes, and slag phophate,.
.;1111 ": 11. in combination with other elements, in I!,-.plh i I rock.
C'li- i -LLI.I is the'most concentrated of all the forms men-.
tioned, and c,.n:.i. lllml. less of this would be required for
iac:'.r-ilil'ii'.. a definite amount of work. There are, however,
some objections to its use. It is rather difficult to handle, and if

Bulletin No. 93. 53

added in large quantities it may injure the land by a too rapid
"burning out" of the humus. Should the application be so
heavy as to render the soil solutions decidedly alkaline, there is
also danger that bacterial development may be temporarily
HYDRATED, OR WATER-SLACKED LIME is less caustic than
quicklime, though it also should be used with caution. Seventy-
eight pounds of this are required to be equivalent to 56 pounds
of quicklime.
AIR-SLACKED LIME is also less caustic than quick-lime, though
it is unpleasant to handle. On long exposure it gradually loses
its caustic properties.
.NATIVE LIMESTONE ROCK, carbonate of lime, when finely
ground, makes an excellent material for correcting acid soils,
it is not particularly unpleasant to handle, and does not have
the caustic properties of the other forms mentioned. It should
be ground to pass a 60-80 mesh sieve, and -should be thoroughly
incorporated with the soil some weeks before the crop is planted,
in order that it may have ample time to neutralize the acids.
There is little danger of doing injury to either the soil or the
crop, even with large applications. Results of comparative tests4
reported by the Lancashire County Council indicate that lime-
stone is a more profitable dressing for soils needing lime than
-either ground lime or coarse quick-lime. One hundred pounds
of ground limestone, provided it is of a fairly pure grade, such
as is used for burning lime, will be approximately equal to 56
pounds of quicklime.
MARL AND SHELLS, if ground, may be used to good ai-lvintag.,
Their \al!u will depend upon the purity of the material and the
fineness of grinding. Sometimes these materials contain the
remains of bones, which would make them more valuable. We
have recently examined samples of material from a shell mound
that contained from 10 to 15 per cent. total phosphoric acid.
This phosphoric acid is probably derived largely from bones.
Such material would be doubly valuable for use on acid soils,

"Use'of Different Forms of Lime (Jour. B.E Agr.) [L.:..l..n] 13
<1907) No. 10, pp. 621-623.

I 1 Florida Agricultural Experinment Station.

:ii.:: much of the pih:.ssplih.:ric acid would ultimately become
HARDWOOD ASHES have been used quite extensively in some
localities as a corrective for acid soils. They are a valuable
material for tlli Ipltrp...,-, and such as are pr-.:.du:e.l on'the farm
should be carefully saved and applied to the land. If they must
be bought, however, they will be found a rather expensive
source of lime. A ton of such ashes will probably cost $1l..i"'
to 31> ii,'. The value of the phosphoric acid and potash in the
ashes would hardly exceed $6.00 per ton, which would make the
cost of the lime $9.00 to $12.00. Such ashes seldom contain
over 25 to 30 per cent. of lime, which would be 500 to 600
pounds per ton. It can thus be seen that half a ton of ground
limestone, which should not cost over $1.75 or $2.00, would
contain as much lime as a ton of wood ashes.
SLAG PHOSPHATE, or TIh-imas slag, is a b.-pr.::dluct in the
manufacture of steel from pig-iron c:iintniinin phosphorus. It
contains from 15 to 20 per cent. of phosphoric acid, and a con-
siderable qtiantlt. of free lime, as well as some magnesia, iron,
etc. If it .is desired to supply the land with phosphoric acid in
addition to co:rrecting the acidity, this material is well adapted
tc the purpose, provided it can be had at a reasonable price.
GROUND PHOSPHATE ROCK, if applied liberally, would slowly
correct acidity, and at the same time the acids in the soil would
attack the rock and gradually liberate phosphoric acid. This,
however, would not give quick returns, and perhaps in most
cases should not be depended upon for quick-growing vegetable
crops; "but should rather be looked upon as an investment that
would slowly furnish available phosphoric acid and at the same
time tend to keep the soil from becoming acid.
NOTE.-LAND PLASTER (gypsum) also contains lime in com-
bination with other elements, but in this form it is not readily
available for correcting soil acidity. However, its application
to soils has proved very beneficial in many instances. It is
generally believed that it aids in retaining ammonia that would
rthier iske be lost by volatilization, and that it is also instru-
mental in liberating potash from certain minerals that are in
the soil.

Bulletin No. 93. 55

Veitch5 conducted extensive experiments to determine in a
practical way the speed with which applied lime neutralizes the
acids of the subsoil. He summarizes his work as follows:
"From this mass of evidence the conclusion seems war-
ranted that for practical farm purposes the neutralizing effect
of applied lime is not exerted below the depth to which it is
incorporated with the soil during the various processes of prepar-
ation and cultivation. Consequently, the more thorough and the
deeper these operations are, the better the distribution and the
more effective the action of the lime.
"The knowledge thus obtained on these points enables us to
say that the incorporation of lime with 3 or 4 inches of surface
soil is sufficient to produce marked effects on acid soils, and also
that at any one time it is needless and possibly occasionally
harmful, so far as the immediately succeeding crops are con-
cerned, to apply more lime than will neutralize the soil to a
depth to which it is to be cultivated. It is the better farm prac-
tice, therefore, to apply only this amount of lime, and immedi-
ately after the next plowing to repeat the application and work
it in.
"These results indicate that alkaline soils are more fertile"
than acid soils, and produce crops more economically than acid
soils do; that in applying lime the soil should finally be made
alkaline to the full plowed depth; that in ordinary farm practice
the acids of the subsoil are not neutralized by applied lime."
No work has yet been done in Florida to determine to what
depth applied lime will neutralize the soil acids.

"Proceedings A. O. A. C. 1904, Bul. 90, Bur. of Chem., U. S. D. A.,
pp. 187.

56 Florida A i, it/l ,,l Experiment Station.



Lab. Depth Descrip- Crop Grown Locality Parts of Lime I r
Number (inches) D tio Cops per Million I'r Cent.

High Pine

1997 0-6 j Soil Cotton-Corn uainesvllle 600 .046
1998 6-12 300
2107 0-6 -..1 400
2108 0-8 -.11 Uncultivated 700
2109 0-8 -. II 800
2110 0-8 -..I11 t 400
2111 0-8 -.. 300
I -': Soil Cotton-Corn 100
:111 u-- Soil 100
2168 0-9 Soil Alachua 100
2169 0-9 Soil 100
2170. 0-9 Soil 1 00
2171 Surface Ve .h, Gainesville 700
2183 0-9 ( Soil .ii....r, Alkaline .026
2184 9-18 ( .ir-.l 1. .010
2185 0-9 ( 200
2186 9-18 -.i.l 100
2187 0-9 { -.ill i 200 .022
2188 9-18 Subsoil 100
2189 0-9 j Soil. Alkaline .023
?onn 9-18 ,, .008
-:.1 0-9 -..1 .025
2192 9-18 I- l. .
.'l,. 0-9 t -, '. .:i, 2191 .031
:I1 9-18 I .... i, .013
i 0-9 i-.II t ..o-- rn
2196 24-36 --.1:. Cotton-Corn 008
0-9 -.11 Alachua
-.1 I-._ Subsoil
2199 u-S Soil .066
2200 9-21 Subsoil .040
201n 0-9 Soil
_1 0-9 Soil "" .044
2203 0-9 .030
2204 9-12 *-..l..I .014
2205 0-9 ( '.il ,Virgin, near 2203 .044
2206 9-21 -. .020
2207 0-9 Soil 2209 .09
2208 9-21 Subsoil .02
2209 0-9 ( Soil Cotton-Corn .057
2210 9-21 i1,...i .028
2211 0-9 1 -..1 V Ir.-in, near 2218 .033
2212 9-21 11..... .017
2213 0-9 ) -..iI I:...Ilon-Corn .029
2214 9-21 I i....1 .015
2221 0-9 I Cotton-Corn Gainesville Alkaline
2222 0-9 -..l "
2228 0-9 '"-11
2134 0-9 ( Soil 1 Citrus Sutherland 600
2135 9-27 I -.,...i Alkaline
2136 0-9 j ...i 1300 .060
2137 9-27 Subsoil 500 .015
2138 0-9 Soil "1400 062
2139 9-27 Subsoil 400 .013
2140 0-9 Soil 500
2141 9-27 Subsoil 200
2142 0-9 5 Soil 800 .032
2143 9-27 ...1i 200 .013
2144 0-9 i 1...Il i '..I,.near2142 800 .037
2145 9-27 I-. ..l11 Alkaline .012
2146 0-9 Soil Citrus 700 ..028
2147 9-27 SubsoilI 200 .014
2148 0-9 i 0...! 800
2149 *-7 i -.1, .1ll 200

Bulletin No. 93. 57

TABLE I-Contiqued

2150 0-9 ( Soil Virgin, near 2148 Sutherland 2 400 .024
2151 9-27 "Subsoil 100 .016
2152 0-9 Soil Citrus 400
2153 0-9 Soil 900
2173 0-9 Soil Bay View 700 .061
2174 9-21 Subsoil 300 .022
2175 0-9 Soil" 1000 .050
2176 9-21 0Subsoil 700 .018
2177 0-9 Soil Virgin, near 2176 400 .036
2178 9-21 "Subsoil 300 .019
2179 0-9 Soil Citrus Keene 400 .041
2180 9-21 Subsoil 200 .018
2181 0-9 Soil Alkaline
2182 9-21 Subsoil 200
2227 0-9 (Soil Virgin, near 2231 Sorrento Alkaline
2228 9-21 Subsoil
2229 0-9 Soil .018
2230 9-21 Subsoil .010
2231 0-9 ( Soil Citrus 200 .031
2232 9-21 1Subsoil Alkaline .014
2243 0-9 ( Soil Orlando 1200 .069
2244 9-21 Subsol 500 .026
2158 0-9 Soil Virgin, near 2160 Winter Haven 200 .028
2159 9-18 Subsoil o 100 .014
2160 0-9 Soil Citrus "100 .029
2161 9-18 Subsoil 100 .013
2162 0-9 Soil Citrus Eagle Lake 400 .034
2163 9- 8 Subsoil 200 .013
2248 0-9 Soil DeLand 100
2249 9-21 Subsoil Alkaline
2250 0-12 Soil .016
2251 12-24 Subsoi" .008
2252 24-36 Subsoil .005
2253 0-9 Soil 400 .024
2254 9-21 Subsoi" 100 .010
2255 -9 Soil 20 .018
2256 9-21 Subsol 100 .0(8
2257 0-9 Soil 400 018
2258 9-21 Subsol Alkaline .006
2259 0-9 Soil 500 .033
2260 9-21 Subsoil 00 .013
2261 24-36 Subsoil 100 .006
2262 0-9 Soil 400 .027
2263 9-21 Subsoil 200 .010
2264 0-9 Soil 100 .037
2265 9-21 Subsoil. 1C .010
2266 24-36 Subsoil 100 .005
2267 0-9 Soil irgin, near 224 Alkaline .018
2233 0-9 1 Soil Cotton-Corn Laurel Hill .031
2234 9-18 (Subsoil .014
2235 0-9 Soil .049
Spruce Pine

1975 0-18 -..i Pineapples Jensen 100
1976 0-18 -.i 1CO ||
Low Pine

2303 Surface Vegetables Miami 1000 .075
2304 0-6 Soil 200 .019
2305 6-12 (Subsoil 100 .008

1943 0-6 Soil Potatoes-Corn Federal Point 1600
2011 0-12 Soil Celery-Lettuce Sanford 500
2045 0-18 Soil Citrus Kissimmee 800
2054 6-12 Subsoil "
--. 0-18 Soil
24-42 -.i..,,l .Lil i..
0-18 -...I
2121 0-9 I *.1 n' l 1 I .022

58 Florida Agricultural Experiment Siati;.'u..

TABL I-Continued

2128 0-9 Soil New land Glen St. Mary 200 .043
2124 9-18 Subsoil Alkaline .012
i -..n... Corn Hampton 300
.1:, i. ,.. 800
2130 0-9 (Soil Cultivated Starke 1000
2181 9-18 Subsoil 300
2268 0-9 J Soil Potatoes-Corn Federal Point 1000 .078
2269 9-21 1i. .- 100 .010
2270 0-9 -*.I Vitell'i ,.*., 800 .058
2271 9-21 i I 100 .010
2274 0-9 I i',.* .. Sanford 300 .082
2275 9-21 -IS ..i 100 .009
2277 9-18 Subsoil Alkaline .011
2278 18-24 -ki ....ii .006
2279 0-9 -.. I. i,.r2276 800 .061
2280 9-21 100 .011
2281 0-9 -..I i ,-. r.,,. 100 .165
2282 9-21 i -.ili. l Alkaline .013
2291 0-9 ( Soil 400 .061
2292 .9-21 ( .ii. Alkaline .006
2293 0-9 -1 .084
2294 9-21 -...i .008
2295 0-9 -' li .... near 229 .079
2296 9-21 i. .012
High Hammock

198) 0-8 Soil Garden Crops Lake City Alkaline
1990 0-8 Uncultivated 200
1998 0-8 R" oses Alkaline
1994 0-8 Uncultivated 200
2217 0-18 Vegetables Florahome Alkaline .086
Cabbage Palmetto Hammock

2237 0-9 ( Soil Citrus Manavista 200 .027
2238 9-20 Subsoil 300 .045
2239 0-9 Soil Alkaline .101
2240 9-20 ( -.i. il .033
2241 0-9 -..A-. -...i 2239 200 .035
2242 0-9 II *. I.. I ", 400 .038
Low Hammock

2216 0-18 Soil Vegetables Florahome 800 .047.
2272 0-9 ( Soil Citrus Boardman 300 .054
2273 9-21 Subsoil 700 .033
2283 0-9 Soil Celery--Lettuce Sanford 1100 .103
2284 9-21 Subsoil 100 .017
2285 0-9 Soil Alkaline .2M3
2286 9-18 -l... .044
2287 0-9 1 -*i ". 200 .054
2288 9-21 ,,1... 100 .010
2289 0-9 -..Hi V i r-. 2287 600 .105
2290 9-21 -.,....1 Alkaline .012
2297 0-9 Soil Celery-Lettuce .160
2298 9-18 Subsoill .026
2299 0-9 Soil .259
2300 9-18 Subsoil .045
2301 0-9 Soil 400 .109

2012 6-18 Uncultivated Kissimmee I.I0,... .i."''' 1.000
2172 | Surface Winter Haven i. .1.i 2.107
2215 Surface "Sanford 1.086
2218 Surface ..'.. Florahome 2.036
2219 f- i ,... [I,,., ,. r,. 1.592
-.rface Vegetables Sanford 2700 I
Tidewar, ,IlMu,, L 'ndr la'id aith Marl

2236 0-12 Uncultivated Hudson Alkaline | 1.795

Bulletin No. 93. 59

cases the samples were collected by a representative of the
Experiment Station, though a small number were collected by
others who are interested in the work. So far as possible the
samples were taken with a sampling-tube which cuts a core
about 3-4 of an inch in diameter to the desired depth. A com-
posite sample was usually made from a number of these cores.
On being received at the laboratory., the samples were air-
dried and passed through a sieve to remove coarse pieces of
organic matter and gravel.
2. METHOD OF ANALYSIS.-In determining acidity, we have
followed the limewater method as described by Veitch.6 We
are well aware of the fact that this method has not as yet been
widely adopted, but we believe that, for the soils with which
we are working, it is the best that 'has yet been devised. The
method is designed to show the maximum lime requirements
of the soil; that is, it shows the amount of lime required under
the most favorable conditions of distribution, to make the soil
just alkaline in reaction.
With slight variations, the length of time the treated and
dried soil was allowed to stand in contact with water was
twenty-four hours.
3. METHOD or REPORTING ACIDITY.-The acidity is reported
as parts of lime per million of soil. If we take 4,000,000 pounds
as the weight of an acre of land to the depth of 12 inches (acre
foot)-and this is the weight usually accepted for sandy soils-,
then 1,000,000 pounds would represent an acre to the depth of
3 inches. That is, the amount given in the column headed
"Parts of Lime per Million" is the amount of lime that would be
required to neutralize the acid in an acre of soil to the depth
of 3 inches.7 If the sample was taken to a depth of 6 inches,
twice this amount would be required; if to 9 inches, three times

"Journal of the American Chemical Society, Vol. XXVI, No. 6.
'Since our work shows rl',i ,1i ,.I-;1t. usually decreases with the
depth, this would perhaps :. I... -i I. true 1..r.r ti.-. ,ri,.- was
taken to the depth of 9 or 1-: '-.-- .- l l .. result. .- ,il,. (. to 3
inches. The first three inches taken under such ...h.iih .-.,,.- ...ilI un-
doubtedly require slightly more lime than the third or fourth three inches.

60 Florida Agricultural Experiment Station.

the amount, and so on. 'It should be remembered that 65
pounds of quicklime are approximately equivalent to 100
pouindr of ground limestone and.l about the same amount of old
air-slacked lnne; hence, for every 100 pounds called for in the
table there should be added approximately 180 pounds of either
ground limestone or old air-slacked lime. To take an example,
soil No. 2185 from Alachua county requires -ii) parts per million
of lime (CaO), which means 200 pounds for an acre to the
depth of 3 inches. For 9 inches, the depth to which the sample
was taken, there would be required three times this amount, or
600 pu.:,nd(. If now it is desired to use finely ground limestone
instea.l of lime, there will be required approximately 180 pounds
of the limestone where 100 pounds of lime would suffice, or
1.lii, pounds for the nine-inch acre.

In Table I are reported 189 samples, representing 17 counties.
From some counties quite a number of samples were secured,
while from others we were able to get only two or three. Pot
this reason the results for a given county cannot be taken as
fairly representing the whole county; but the results taken as a
whole indicate that an acid condition of the soil does exist in
many localities throughout the State. A careful examination
of the -table shows that 68.22 per cent. of the soils8 (muck soils
not included) are more or less acid, while 51.35 per cent. of the
subsoils are acid. With only two or three exceptions, however,
the subsoils are de.-iedly less acid than the soils, the difference
in some cases being as great as ten to one.
The average lime requirements of the soils and subsoils. that
are acil are as follows:
Average of 65 cultivated soils, 497 parts per million.
Average of 33 subsoils, 242 parts per million.
Stated in other words, the average of 65 cultivated soils
shows a lime requirement of 497 pounds per acre thive-iinclies.
or 1,491 (497x3) pounds per acre nine-inches. The average
"TL ..r. :.. Il in rl TM,: I i- uir.:. to designate the depth to which the
t.:.) -r .l I '. I ii. a3111 c. n.-.ri therefore always indicate the depth to
,I. b~h ln .l } ,' I ,,,,] ,,> 1 > l i ,.,l

Bulletin No. 93. 61

of 33 subsoils shows a lime requirement of 242 pounds per acre
three-inches, or 726 (242x3) pounds per acre nine-inches. From
this it would appear that the average cultivated soil here reported
as acid would require approximately 1,500 pounds of lime per
acre to neutralize the acidity to a depth of 9 inches; or about
2,000 pounds to the acre-foot. There is, however, a wide differ-
ence between the maximum (1,600 parts per million) and mini-
mum (100 parts per million) amounts required, and it should
be borne in mind that it will not be safe to judge all soils by
the average lime requirements.
The difference in lime requirements between soils and sub-
soils, we believe, may be taken as evidence that there is a close
relationship between soil acidity and the organic matter in the
soil, since there is decidedly more organic matter in the soils
than there is in the subsoils.' This point is further emphasized
by the results shown in the column giving the percentages of
nitrogen. The results given in this column (muck soils excepted)
may be summarized as follows:
Nitrogen in cultivated soils .......... .0606 per cent.
Nitrogen in cultivated subsoils........ .0195 per cent.
Nitrogen in cultivated 2nd subsoils.... .0060 per cent.
Nitrogen in virgin soils.............. .0437 per cent.
Nitrogen in virgin subsoils........... .0145 per cent.
Nitrogen in soils from citrus groves.... .0405 per cent.
Nitrogen in subsoils from citrus groves, .0170 per cent.
It will be noted that, with only one or two excepti.un. the
soils contain more nitrogen than the subsoils. This seems
entirely in harmony with the statement already made, namely,
that there appears to be a close relationship between .acidity and
the organic matter of the soil.9
the soils and subsoils that are. here reported, there are 16 vir-
gin soils and 14 virgin subsoils. Of these soils 50 per cent.

'The IEiat that certain alkaline soils contain as much nitrogen as others
that are a,:id ..ould not disprove this relation-hip. hince in the former
case there niY be sufficient bases pre-mnt to neutralize the acids a4 rapidrl
as they are formed; as in the case of shell mounds or limestone depo-itw

62 Florida Agricultural Experiment Station.

are acid, while 35.7 per cent. of the subsoils are acid. Their
lime requirements are as follows:
\Aerage of.,,8 virgin, soils, 400 part- per million.
.Averae: of 5 virgin subsoils, 140 parts per million.
"Comparing these figures with the cultivated soils that were
found to be acid, it will be seen that the percentage of samples
that are acid is lower in the virgin soils; and also, that the
acidity or lime reiluir.nmenit of the virgin soils is lower. This
latter fact we would interpret as giving further evidence that the
c.nltinllued chulti\aiiin ani.l fertilization of our sandy soils tends
towards an acid condition, since the virgin soils have not been
influenced by either 9f these agencies.
The decrease of lime requirement and nitrogen content as
the depth increases, is well illustrated by Nos. 2303, 2304, and
2305 in the table.
EXCEPTIONS NOTED.-A. few exceptional cases should here
be pointed out:
The garden soil and the rose soil from Columbia county
had received liberal apr-licati.:ins of ashes for several years, and
it was to be expected that they would be alkaline. Nos. 1990
.and 1994, taken only a few ftct away from the garden and rose
soils, but not under cultivation, were acid. Many of the celery
and lettuce growers of Sanford use large quantities of wor4-
a.shes, and many barrels of lime are used during a season lo,"
spraying, which undoubtedly accounts for the alkalinity ol some
of the samples taken at that place. It will be noted that some
of the samples taken there are quite acid. No. 2297 was taken
where material from a shell mound had been, scattered over a
lettuce field, and this would easily account for the alkalinity of
the sample. The parts where this material had been scattered
cjuld easily be detected by the better condition of the lettuce.
No. 2302, taken not many rods away from No. 2297, was highly
As has already been pointed out, the soils in a number of
iances in Alachua county contain a great deal of phosphate; and
their alkalinity is probably due to the lime and other bases that
are associated with the phosphate. This is especially true of the
soils around Alachua.

Bulletin No. 93. 63

finding out if there is any practical relation between the acidity
as shown by the limewater method and the crop yields, an
experiment was conducted using' the wire basket method, as
described by Whitney, Circular No. 18, Bureau of Soils. A
sample of soil was chosen that showed a lime requirement of
about 500 parts per million (2,000 pounds per acre-foot). This
soil was divided into three equal portions. To one no lime was
added; to a second, finely ground quicklime was added at the
rate of 500 parts per million; and to' the third portion, quicklime
was added at.the rate of 1,000 parts per million. Each portion
was intimately mixed and kept moist with distilled water for
three days, being thoroughly stirred several times. The soil
was. then placed in the baskets, three baskets being filled from
each lot. The baskets were then dipped in paraffin and sealed.
Each basket held 400 grams of soil. On August 7 germinated
beggarweed seeds were placed in the baskets in two parallel'
rows, three seeds to the row, and covered with a thin layer of
clean, white sand. The weights were recorded, and water was
added from time to time to make up for the loss by evaporation,
thus keeping the soil in the most favorable condition for plant
growth. The soil was a poor sandy soil, containing but little
organic matter, and no fertilizers whatever were used. At the
end of about a week the plants were thinned to a stand of four
to the basket. When about two or three weeks old the tips of
the leaves of the plants in the unlimed baskets showed a
brownish, dead appearance, something like tip burning; and this
condition continued throughout the experiment. The leaves of
the other two lots were not in the least affected in this way.
With the exception of the liming, the soil and plants received
the same treatment. On October 21, the plants were cut off at
the surface and immediately weighed. The results are shown
in Table II.

(i 1 Florida Agricultural E., p'lriE'nt Station.


Green Weights Dry Weights
Lime, 500 Lime, 1000 lhme. III Lime. lIJ).
No Lime parts per parts per No Lime parts per parts per
million million million million
Basket N I l l- rin im: i I- -CraII .- "r .l ni
Basket No. 2 .325 1.617 1.586 "
Basket No. 3 1.78 1.450 1.696 "
Total 4.800 1.879 ', I .' :4 L'-.
Per cent. gain 17.3 23.6 19.8 26.47
over no lime
Per cent. gain
over lime 'I
the rate .1 540 5.57
500 parts per

Reference to Table II shows that there is a gain in green
material of 17.3 per cent. in the baskets receiving lime at the
-ate of 500 parts per million over those receiving no lime;
while those receiving 1,000 parts per million have made only a
slight gain' over those receiving 500 parts per million. This
may indicate that the acidity was practically neutralized with
500 parts per million. It will be remembered that according to
the limewater method this soil showed a lime requirement of
about 500 parts per million.
It will be observed that the yield is small for nearly two
m...nths' growth. This is accounted for by the fact that the soil
was very poor, no fertilizers were used, and the amount of soil
also was small f:r four plants.
Fie. 1 shows these plants as they were a short time before
b1cinll cut.
STONE.-A somewhat similar experiment was tried with a sam-
ple of muck soil, though in this case the object was to test the
effectiveness of finely ground limestone as a neutralizing material
for highly acid soils. These muck soils are usually much more

Bulletin No. 93. 65

I 3

Photo by H. S. Fawcet.
1. NO lime.
FIG. 1. .Limed. 1)01 part per million.
3. .imed. 1.110

Pheto. by H. S. Fawcett.
FIG. 2 1. N,o lime tone.
FI. 2. 2. Limestone, 8,000 parts per million.

66 Florida Agricultural Experiment Station.

acid than ordinary soils, but on account of the very dark color
which the organic matter imparts to the solution we have so
far found it almost impossible to determine their lime require-
ments with any degree of accuracy. The sample for this experi-
ment came from Winter Haven, and was a mixture of saw-
grass and pond muck. It contained 2.2 per cent. of nitrogen.
The muck was mixed with twice its weight of clean, white sand
to give it more of the consistency of soil, and divided into two
equal portions. To one portion no limestone was added; to the
other, finely ground limestone was added at the rate of about
8,000 pounds per million. These portions were kept moist for
two or three days, with occasional stirring, and then the baskets
were filled as in the former experiment. Four1o baskets were
prepared with the untreated soil. and four with the treated. On
November 16, germinated beggarweed seeds were planted in
all the baskets, and throughout the experiment both sets were
treated as nearly alike as possible. Water was added from
time to time to supply that lost by evaporation and transpiration.
When the plants were a few weeks old it was easy to see that
those in the baskets receiving limestone were larger and more
vigorous than the others; and from this time they gradually
gained on the others. On December 7 they were thinned to a
stand of' four plants to the basket. The tips of the leaves of
the plants in the untreated baskets turned brown and developed
slowly, just as in the former experiment. The appearance of the
two sets, as shown by a photograph taken February 21, 190.
may be seen from Fig. 2. These plants were cut and weighed
on March 2, 1908. The green and dry weights of the tops and
the drytweights of the roots, together with the percentage in-
crease in .i.:11 .due to the use of the limestone, are shown in
Table III. The roots were carefully washed and dried before
being weighed. It was especially noticeable that the roots from
the plants receiving no limestone were almost devoid of nitrogen-
gathering tubercles; while those from plants receiving the lime-
stone were fairly well supplied with tubercles. It thus appears

One of the treated baskets was lost during the experiment, and for
this reason results are reported on only three in each set.

Bulletin No. 93. 67


Green Weights Dry Weights
No Limestone Limestone No Limestone Limestone

Basket No. 1 .6477 grams 1.1355 grams .2010 grams .3822 gram
2 .6300 1.1560 .1925 .4040 "
3 .4300 1.1110 .1317 .3700 "

Total 1.7077 .4025 .5252 1.1562 "
Percentage increase 99.24 120.1


Basket No. 1 .2240 .2633 "
2 .2180 .333 "

3 .1254 .3202 "
Total .5674 .9168
Percentage increase 61.58

that the presence of limestone favors the development of root
tubercles, and thus adds to the soil's supply of nitrogen.
To double-the yield of a crop by so simple a method as the
application of finely ground limestone means much. It is hardly
probable that such an increase can be looked for in actual field
practice. This yet remains to be seen; but even a smaller gain
is worth striving for, and there is little question but that, in the
case of certain soils, limestone will make the conditions for plant
development more favorable. Other experiments along this line
are now in progress, and field tests will also be made.
Some may 'hesitate to use lime on muck soils, fearing that
it will cause a loss of ammonia. However, such fears need not
be entertained if the muck is highly acid, as is the case with
most Florida mucks. Lime and the organic acids contained in
the muck have a tendency to destroy the properties. each of the

68 Florida A,' icltral Experiment Station.

other, 'and thus the lime is rendered powerless to liberate
Florida mucks, when air dried, usually contain from one to
three per cent. of total nitro:.gcln. and if we take two per cent. as
the average, an acre-foot of such muck would contain 13 to 20
tons of total iitr,-.ecn. An acre-foot of the average cultivated
soils in Florida will contain in the neighborhood of one ton of
total nitrogen. It will thus be seen that even should a small loss
of nitrogen occur through the use of lime on muck it would not
prove serious. We would, however, advise, in the place of lime,
the use of d liberal application of finely ground limestone for im-
proving muck soils.

(1) Florida soils are composed very largely of sand which
has been derived from disintegrated rock. Ori' : minerals
c.-lt:iniin, bases and other compounds were associated with this
sand, but these being less resistant to the action of the elements
than the sand, have to a large extent been dissolved, or carried
into the sea in the form of mud or silt. As a result our soils are
in many cases very deficient in bases, such as potash, lime, and
(2) There are agencies at work producing acids in practi-
cally all cultivated soils, and unless there are sufficient bases
present to neutralize these acids, the soils will tend to become
permanently acid. Our work shows that such are the conditions
over a considerable portion of Florida.
(3) These acids may be the result of decomposing or.zanic
matter, of bacterial action, or of the breaking up of commercial
fertilizers. They may also be due to other causes not well
(4) Such acids may have a direct detrimental effect upon
the plants themselves, or upon beneficial bacteria; or they may
bring into solution mineral compounds that are injurious to the
plants or the bacteria. Thei may also bring into solution plant-
food elements.
(5) To counteract these acids, the base, lime, in some of
its forms may be used. Finely ground limestone (the native

Bulletin No. 93. 69

rock) is to be preferred to the forms commonly used, since it is
effective, is more easily handled, and harm is not likely to result
from the use of amounts in excess of what is needed to neutralize
the acids.
(6) In Table I, 189 samples of soils and subsoils, represent-
ing 17 counties, are reported on. Of these, 68.22 per cent. of
the soils, and 51.35 per cent. of the subsoils were found to be
more or less acid according to the limewater method. With
only one or two exceptions the soils are more acid than the
subsoils, and the cultivated soils are more acid than the virgin
soils. With one exception the muck soils examined are ex-
tremely acid.
(7) According to the method employed, the average lime
requirement of the soils here reported as acid, is approximately
500 parts per million (1,500 pounds per acre nine-inches).
(8) about three times as much nitrogen in the soils
as there is in the subsoils; slightly more than three times as much
in the subsoils as in the second subsoils; and nearly one and a
half times as much in the cultivated soils as in the virgin soils.
(9) Experiments by the wire basket method showed a ga:n
in baskets where lime was used, over baskets where no lime w\
used, of 17.3 per cent. green weight, and of nearly 20 per cent.
dry weight. With a muck soil which was very acid, the gain
in baskets where finely ground limestone was used, over baskets
where no limestone was used, was nearly 100 per cent. green
weight and 120 per cent. dry weight.

University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs