Relation of calcareous soils to pineapple chlorosis

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Title:
Relation of calcareous soils to pineapple chlorosis
Series Title:
Bulletin / Porto Rico Agricultural Experiment Station ;
Physical Description:
45 p., ii leaves of plates : ill. ; 24 cm.
Language:
English
Creator:
Gile, P. L ( Philip Lindsey ), 1883-1972
Publisher:
Porto Rico Agricultural Experiment Station
Place of Publication:
Mayagüez, P.R
Publication Date:

Subjects

Subjects / Keywords:
Chlorosis   ( lcsh )
Calcareous soils -- Puerto Rico   ( lcsh )
Pineapple -- Puerto Rico   ( lcsh )
Genre:
government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references.
Statement of Responsibility:
by P.L. Gile.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029615384
oclc - 21269457
Classification:
lcc - S181 .E2 no.11
System ID:
AA00014640:00001


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iiai # Imued November 7, 1911.

P PORTO RICO AGRICULTURAL EXPERIMENT STATION,

D. W. MAY, Special Agent in Charge.

Mayaguez, May, igx.



Bulletin No. 11.
i:! -.: "





SREILATION OF CALCAREOUS SOILS


TO PINEAPPLE CHLOROSIS.












CHEMIJST.
*i*' .. .










... .::: ....
CiP.. .... :












UNDER THE SUPERVISION OF
;... ." ...



















OFFICE OF EXPERIMENT STATIONS,

U. & DEPARTMENT OF AGRICULTURE.
:: .






















WASHINGTON:
GOVERNMENT PRINTING OFFICE.
.1911.




































, ,r.


o0


rsaem


STATION STAFF.


D. W. MAY, Special Agent in Charge.
OSCAR LOEW, Physiologist.
W. V. TOWER, Entomologist.
P. L. GILE, Chemit.
G. L. FAWCETT, Plant Pathologist.
C. F. KINMAN, Horticulturist.
E. G. RIrrTAN, Animal Husbandman.
T. B. McCLELLAND, Assistant forticulturist.
C. N. AGETON, Assistant Chemist.
W. E. HESS, Expert Gardener.
CAUMELO ALEMAR, Jr., Stenographer.


.,


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.:...;iii














LETTER OF TRANSMITTAL.


PORT RICO AGRICULTURAL EXPERIMENT STATION,
Mayaguez, Porto Rico, May 1, 1911.
Sm: I have the honor to transmit herewith a manuscript on the
subject of Relation of Calcareous Soils to Pineapple Chlorosis. Owing
to the great increase in importance of this fruit in Porto Rico any
investigation leading to its improvement is timely. The number of
failures occurring in certain soils which apparently are well adapted
to pineapple growing lends value to the results as set forth in this
manuscript, which offers an explanation of the cause of the failures
and suggests means of avoiding great losses in the future.
I respectfully recommend that this manuscript be issued as Bulletin
No. 11 of this station and that it be published in both English and
Spanish.
Respectfully, D. W. MAY,
Special Agent in Charge.
Dr. A. C. TRUE,
Director Ofice of Experiment Stations,
U. S. Department of Agriculture, Washington, D. C.
Recommended for publication.
A. C. TRUE, Director.
Publication authorized.
JAMES WILSON,
Secretary of Agriculture
[Bull. 11] (3)


















CONTENTS.






Investigations of pineapple soils.................... ...........- ...r......
Chemical survey of the pineapple soils of Porto Rico....-----.-..........
Pineapple soils of other countries.....--------........................-........
Pot experiments with different types of oil..---.....-------...............---------- ..
Experiment with plants grown in smnal aeld plats...-.- ........- ..ii
Conclusions from soil investigations,......,..-..-. -.......,.....
Investigations of the chlorosnis.--... ,..-..,-.....-..., .....-............*,
Previous work on lime-induced clorois--....-.....--......................
Effect of soil alkalinity and assimilable lime in causing chlorosis.... ....
Treatment of chlorotic plants with iron and other alt------...... ..... .
Ash content of green and chlorotic leaves...................... ...
Enzyms in chlorotic and green leaves..--....-..-.......................
Effect of light on the chlorosis----..........-............b.......... ..-.









PLTE NOrmal green plant and two stages of chorosis ......... rontisp
ILLUSTRATIONS.

P"a.
PLATE I. Normal green plant and two stages of chlorosis............. Frontflspie~i
II. Fig. 1.-Effect of carbonate of lime on the growth of pineapples.
Fig. 2.-Effect of ferrous sulphate on chlorotic pineapple plants... .
[Bull. 11] (4)




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RELATION OF CALCAREOUS SOILS TO PINEAPPLE
CHLOROSIS.


INTRODUCTION.

HISTORY OF PLANTINGS ON UNSUITABLE SOILS.

Raising pineapples on a commercial scale is a comparatively new
but rapidly growing industry in Porto Rico. As more and more land
is being planted to pineapples it is becoming apparent that all of the
loose, well-drained soils are not adapted to this crop. On certain
well-drained soils of good physical condition the pineapple plantings
have been very unsuccessful. The failure of these plantings has been
attended by a peculiar bleaching" or chlorosis of the plants, in some
cases so complete that the leaves contain hardly a trace of chlorophyll.
The investigation detailed in the following pages was undertaken
for the purpose of discovering the cause of the chlorosis and the failure
of the crop on these soils.
The first instance of the plants presenting this peculiar bleached
appearance on a well-drained soil was noted at Rincon, P. R., by Mr.
H. C. Henricksen in 1904, and is described in the annual report of this
station for 1905:2
In the fall of 1903 about 2 acres were planted at Rincon with the variety Cabezona.
The plants were reported to be diseased and the field was visited April, 1904, at the
owner's request. The plants were found to be of normal size, but the color of the
leaves was of a light red to pure wax white, about 50 per cent being entirely devoid of
chlorophyll and less than 15 per cent showing green, the rest red, green, and white
mixed. The field was located near the ocean, but in no way injured by salt water.
The soil, which was a beach sand, had recently been cleared of its natural growth,
consisting mainly of coconut, sea grape, coco plum, a few sour orange trees, and the
usual tropical shore-line plants.
Since this case was reported numerous other instances of pine-
apples showing the same appearance have been noted. On two
plantations, of about 10 acres each, the plants became almost uni-
formly yellowish white and ultimately succumbed. About 60 per
I Chlorosis (sometimes called icteruss," "bleaching," or Gelbsucht") is the term applied to that con-
dition assumed by the leaves of plants when they fail to develop the normal amount of chlorophyll, or
green coloring matter, i. e., when they are yellowish or white instead of a normal green. Chlorosis, then,
does not denote a specific disease, but merely a general condition. This condition of chlorosis, however, is
the result or outward sign of a disease or disturbance in the physiology of the plant. To say that a plant
is "ehlorotic," or affected with chlorosis, means merely that its leaves are lacking in chlorophyll; but the
chlorosis may have resulted from a bacterial disease, poor drainage, lack of nutriment, or some other cause.
2 Porto Rico Sta. Rpt. 1905, p. 30.
[Bull. 11] (5)







cent of the plants *in another 1 0--acre field -ar-e now kina
way* Several fields of I or 2 acres with'the same symptona
been lost, and numerous cases of a few hundred plants hwg
peculiar chlorosiss have beCen observed 'in different plantation
The places where the chlorotic plants occurred W-ere not 0on0,P
any one district of the island or-toan one physical type of soil.
APPEARANCE OF PLANTS ON UNSUITABLE SOILS. .
The degree to which the plants wore affected and the age oof
Plants when the bleaching first manifested -itself varied someha
the different instances. in some places many plants became Am
ivory white, apparently without a vestige of chlorophyll; later
leaves of such plants showed brown spots and the plants fin
decayed. In other cases the leaves were a Yellowish white, w1t
streaks and small patches of green. Sometimes the outer les
remained a light green while the new heart leaves were creamy w
In other cases the leaves were for many months practically
in color, but gradually light spots appeared, producing a mat
appearance, and finally, in 14 or 15 months he leaves bleached oiit
a uniform greenish -yellow. The lack of chlorophyll,. orcho i
was generally very pronounced when the plant was 9 months 0
though sometimes it appeared in 3 or 4 months, and sometimes i
not appear until the plant was 15 or 16 months old.
The root system of the chlorotic plants showed no evidence
disease. The roots differed from those of normal. plants in. bei
somewhat longer and not so thick; they were more like those of plan
suffering from starvation. The plants, however, that had suffer
from the chlorosis for some time had many dead roots, but the u
tioning roots appeared to be perfectly healthy and on exammiation I
the pathologist'failed to show any bacterial or fungus trouble.
PRELIMINARY INVESTIGATIONS.
From the fact that the first examples of the chlorosis appeared
Plantations near the sea it was thought by some that the trouble w
caused by sea spray being blown in on the plants. This was sho
not to be the case, however, as on some plantations within lass
a hundred yards of the sea the plants. -were perfectly green i
healthy and later, the distinctive chlorosis was observed On- plan
tions several miles from the coast; moreover, plants heavily. spra
with sea water for four consecutive days showed no injury. My
It was also thought that the chlorosis might be attributed to Iac
aeration of the roots from poor' dramiage. in some places where
chlorosis occurred the drainage was poor, and in the spots of poq
dirainager the chlo"Losis was most intense. In other places, how-0





7

plants on loose, sandy soils of perfect drainage became strongly chlo-
rotic. It was thus apparent that although the trouble was intensi-
fied by poor drainage, faulty drainage was not the primary cause.
The appearance of patches of chlorotic plants in the midst of
fields that were for the most part green and vigorous made it seem
probable that it was a bacterial disease. But investigations by the
pathologist failed to reveal any bacterial or fungus disease. The
fact that chlorotic plants on transplanting to different soils in every
case recovered also militated against this view. Chlorotic plants and
soil were secured from three different plantations and placed in pots.
The chlorotic plants in the original soil in all cases remained without
change, while those placed in a river sand became, in a short time,
green and healthy. Also, since these investigations were started 6
acres of chlorotic plants have been taken up and set out in soil of a
different character. Here they became green within a month or two,
and, in the year that has elapsed since transplanting, not a single
plant has developed the chlorosis. Had the plants been infested with
bacteria or fungi they could hardly have shown such a uniform
recovery on transplanting to different soils of a similar physical
character.
Experiments with commercial fertilizers and stable manure were
tried in 1904 and 1908 by the horticulturist on two of the plantations,
where the chlorosis was very marked, to see whether the trouble could
have been caused by lack of nutriment.
It was found that although the complete fertilizers improved the
condition of the plants slightly, they were without much effect. The
stable manure produced slightly more improvement than the com-
mercial fertilizers.
It being, then, seemingly impossible that the chlorosis could have
been produced by disease, lack of nutriment, poor drainage, or injury
from the sea, it was thought probable that the cause was to be found
in the unsuitable chemical character of the soil. Accordingly, soils
were collected from all the areas where the chlorosis occurred and
from adjacent fields where the pineapples were doing well. In some
cases patches of a few hundred chlorotic plants occurred in the midst
of several acres of healthy green plants. Hence, it was to be expected
that, if the trouble was due to the chemical character of the soil, a
difference would be apparent in the analyses of the soils where the
healthy and unhealthy plants were growing. In addition to such
comparative analyses, analyses were made of most of the well-drained
soils where pineapples were growing well. It was thought that,
should the soils producing chlorotic plants show a chemical character
that adjacent areas with healthy plants did not, and should none of
the good pineapple soils show the same characteristics as the bleached
areas, the specific cause would become apparent.
[Bull. 11]



















by absorption and from this the percentage of anlni iarl
calculated. This does not give a strictly tecurate b1Mi
of the lime present as carbonate, inasmuch as it fails to dlt
between calcium -and magnesium carbonate. For the jp IeP
however, the method suffices. The oxide of liUe and moagoi ia w
of course exactly determined in the acid digtstion.
All of the following samples were tested for water soltib a
salts and chlorids, but none was found present. The alsaliae -mme
of certain of the soils is due to the presence of the carbonatesa3r4i
and magnesium.


SOIL SURVEY I.


* HLh
h ~~~1:j


Plantation (Isla Verde) of Mr. Noble, about 5 miles amD it M
turce, P. R.: Here there were 10 aice of Red Spatm*h p'il
on a loose, well-drained, gray sand, a few hundred yardc ftria the ....
The surrounding vegetation consisted of ica0os, Santa M~tia, *
and leguminous weeds and low growing bushes. In 90 o 10 maWe
th e plan ts h ad all b ecom e ch lorotic w ith th e ex cep tion at aI
patch at one corner of the field and a few scattered indihdvdu* fl
few isolated plats later lost their color, whie in the 2-Mar paM
they did not lose their green color up to the time of fro tlag s
produced fruit of sizes 18, 24, and 30 at the rate of 300 boe pr aM
The plants were fertilized at various times with a eoiplete pna-ppl
fertilizer.
A year after planting, about 6 aeres of chlomrti plants wre taxb
up and set out in a field a quarter of a mile farther in&nd on &l"d4a
sandy soil, of.finer texture than that of the original field. The pli
soon recovered their normal green color sad have continued tW
well without showing any chlorosis.
Below are given the soil analyse. Samplee 101 dat 10 ij
taken from patches where the plants became chloaNtiN; No. 7 .is
subsoil beneath chlorotic plants; No. 192 is hmI the on4er oi;
field where the chlorosis failed to appear; No. 152 ti a saanpI f1
the field to which the plants were transplanted with a cm.l.I
recovery. :-
[Bull. 11]


'.=..







9

Analyses of pineapple soils.


Soil constituents and reactions.


Insoluble matter.........................
Potash (K0)............................
Lime(CaO) .............................
Magnesia (MgO)..........................
Ferric and aluninic oxids (FesOa andAlsOs)
Phosphorus pentoxid (PsOs)..............
Volatile matter ............................
Total.............................
Nitrogen (N)............................
Moisture ................................
Carbon dioxid (CO2).....................
Calcium carbonate (CaCOs)............-
Reaction to litmus... ..............


No. 79.
(plants
chlorotic).


No. 101.
(plants
chlorotic).


SI I


Per cent.
54.04
.06
22.27
2.01
.79
.04
20.79
100.00


I I


.02
1.37
Alkline......
Alkaline.


Per cent.
56.85
.03
20.40
.78
2.06
.05
19.87


100.04


.12
4.01
14.88
33.85
Alkaline.


It will be seen by the above analyses that the soils where the plants
became chlorotic contain a large amount of carbonate of lime, that
the soil where the plants remained healthy contains a trace, and that
the soil where the chlorotic plants recovered contains but little lime and
no carbonate of lime.
SOIL SURVEY II.

Plantation of the Bird Bros. at Luquillo: This planting of Red
Spanish pineapples consisted of about 10 acres or more; it was on a
loose sandy soil a few hundred yards from the sea. The pineapples
were planted between coconut trees. The soil was of good physical
condition, but the land was so low that the drainage was poor. After
very heavy rains the water was found standing within 12 inches of the
surface.
The chlorosis here was more marked than on any other plantation.
When 6 or 8 months old most of the plants were waxy white. At the
end of 18 months many plants were dead, the greater part of the
remainder were colorless, while a few were of a light green with long
spiky leaves. About a dozen plants with very small fruits were found.
On no part of this field were the plants vigorous. The analyses of sam-

ples of soil taken from various parts of the planting are given below:
Analyses of pineapple soils (plants chlorotic).


Soil constituents and reaction.


Insoluble matter..................................................
Potash (KO)............................................ ........
Lime (aO).....................................................
Magnesia (MgO).............................................
Ferric and aluminic oxids (FesOs and AlOs)..................
Phosphorus pentoxid (POs) .......................................
Volatile matter.............................. ...................
Total........................................ ... ..........
Nitrogen (N)...............................................
Moisture.......... ...............................................
Carbon dioxid (CO) .................................... ..........
Calcium carbonate (CaCO)......................................
Reaction to litmus..............................................


No. 163.


Per cent.
7.84
.19
44.73
2.26
3.16
.16
42.25


No. 191.


Per cent.
3.53
43.49
1.43
4.71
.17
45.87


100.59 ....... ............


.20
1.78
35.03
79.70
Alkaline.


.19
1.70
33.55
76.33
Alkaline.


4120-Bull. 11-11-2


No. 102.
(plants
chlorotic).


No. 132.
(plants
healthy).


Per cent.
............
............
............
............
............


............
Trace.
Trace.
Alkaline.


Per cent.
56.69
.03
19.54
.86
2.12
.06
21.23


.22
4.42
14.14
32.17
Alkaline.


No. 152.
(plants
healthy).

Per cent.
89. 76
.08
.15
.77
5.70
.03
3.16
99. 65


.06
.43
Trace.
Trace.
Neutral.


No. 194.

Per cent.
3.13
42. 94
5.78
3.08
.20
44.29


.27
1.90
35.06
79.76
Alkaline.


I I


100. 53




























pure white; the others were of fair size with very light gr~e iV
leaves. The soil sample from near tte roots of these pJlaMtJ W'
A quarter of a mile farther on a small patch of a1ih out
Cabezonas and Caraquefas were found gr-owing. A, hAff:
were of small size and light-greenish yellow oryellow-W*idtjt ii
A few plants were bearing dwarfed fruits. The soil from thi
is designated as No. 226. The soil in testhree casds WiAt
same character, a coarse, well-drained, beach sand with a 'ftif t'


of organic matter. Coconuts, oranges, and gandules
seemed to grow well here.


or pig
.: ,-
".. ; .'r :. E":.
T :.i..


Analyses of pineapple soils (plants dchorat).


Boil constituents and reaction.


Insoluble matter.................................................
Potash (KO) ........ ......................... .......
Lime (CaO). ..... ... ..---------------
Magnesia (MgO)........................................ .....
Ferric and aluminic oxids (FesOa and AlsOaa)........ ............
Phosphorus pentoaid (PS6)................................
Volatile matter.............................................
Total..................................... ............... ..
Nitrogen (N)..................................... ...............
Moisture........................................... ............
Carbon dioxid (COg).................... .......... ..............
Calcium carbonate (CaCOs)....--...........--.......................
Reaction to litmus......................................


No. 224.


70. 15

.30
4.00
.-W
12.95


.09
.69
7.98
18.04
AIlifife.


No. 22 ,




1.0
la.el0


* ft ....
'Ai
3:


I9'4 I -1


.10
.76
9.87
21.77
Alkaline.


These soils are slightly richer in potash and phosphoric aeti
in Survey I and not so high in lime, but they are still to beng,
as strongly calcareous. .
SOIL SURVEY IV. : :

Property of Mr. William Gay, Dorado, P. R.: Here about 2,j
of red Spanish pineapples were set out on a sand near th sea.:
soil was of good physical character with considerable egatko nf
[Bull. 11]
.. ^ii.i;iiiii

...... :, :[[E" i


Alii








but so low that during heavy rains the ground water approached the
surface. Most of the plants did fairly well, but a strip about 10
yards wide, running transversely across the field, exhibited the char-
acteristic chlorosis, having ivory white leaves with small patches of
green. The field had been fertilized with stable manure. Citrus
fruits and gandules grew exceptionally well on this plantation. Sam-
ple 148 is of the soil where the pineapples were healthy, and 149 is
from a patch of chlorotic plants. These samples were taken by one
of the station staff. Sample 154 is another sample of the bad soil
and 155 of the good soil sent in by Mr. Gay. The samples of good
and bad soil were taken only a few yards apart.

Analyses of pineapple soils.

No. 148 No. 149 No. 154 No. 155
Soil constituents and reaction. (plants (plants (plants (plants
healthy). chlorotic). chlorotic). healthy).

Per cent. Per cent. Per cent. Per cent.
Insoluble matter.................. ............... 93.28 44.02 63.19 93.17
Potash(KsC)......................................... .07 .04 .32 .22
Lime(CaO)........... ............ ................ 1.92 22.19 16.02 1.00
Magnesia (MgO)...................................... .14 2.50 1.58 .37
Ferric and aluminic oxids (FeLOs and AlsOa)........... .51 2.31 1.59 .91
Phosphorus pentoxid (PO) ........................... .04 .09 .07 .02
Volatilematter............... .................... 4.12 27.84 18.16 3.51
Total ........ ......... ........................ 100.08 98.99 100.93 99.20
Nitrogen (N).......................................... .08 .30 .22 .11
Moisture.......................................... .58 .27 3.30 1.07
Carbon dioxid (CO) ............... ................ .50 16.96 10.69 .09
Calcium carbonate (CaCO) ........................ 1.14 38.56 24.32 .20
Re tion to litmus.............. ..... .............. Alkaline. Alkaline. Alkaline. Alkaline.

It will be seen that 149 is, on the whole, richer in plant food than 148
but that the bad soil is here again strongly calcareous while the good
soil has but little calcium carbonate. The same difference is true of
154 and 155. The calcium carbonate in the bad soil plainly originated
from disintegrated coral.
SOIL SURVEY V.

Property of Mr. PizA, Dorado, P. R.: This plantation consisted of
about 30 acres of red Spanish pineapples. The greater part of the
plants were on a white, almost pure silica sand; the rest of the plants
were on a red clay of varying stiffness. Only two patches of chlo-
rotic plants were found. These were growing in a fairly stiff loam
on a hill near the seashore. In one spot there were three small
plants almost ivory white in color. These were surrounded by large
vigorous plants of a dark-green color. Sample 197 is taken from
about the roots of the white plants. The soil here, however, was
only 3 inches deep, and the roots of the plants were directly on the
surface of the coral rock; there were numerous coral nodules in the
[Bull. 11]
























Analyses of pineapple soil.
.---------------------------------------. ----.*..-.,,.
No. 197 No. 198 No. 199 No. a1
Soil constituents and reaction. (plants (plants (plt a pl
chlorotic). healthy), horotc). hat )

Per cent. Per cent. Per cet. PeaS g.
Insoluble matter ............................... ..... 73.91 83.08 79.4
Potash (KIO)....................................... .20 .24
Lime (CaO)..................... ...................... 5.17 1.44 3.41
Magnesia (MgO)............................. ..... Trace. .42 .8..
Ferric and aluminic oxids (FesO and A iOa)........... 9.24 6.08 G.6
Phosphorus pentoxid (PsOa) .......................... 1.13 .09 .08
Volatile matter........................................ 11.65 8.71 8.93 ::


Total...........................................


100.30 100.01 99.13
7.. .


Nitrogen (N)..................................... .40 .29 .22
Moisture........ .................................. 3.32 4.10 3.34 1
Carbon dioxide (COs)...........-................... 2.03 .00 122
Calcium carbonate (CaCOs)........ .................. 4.62 .00 5.05
Reaction to litmus................................... Alkaline. Alkaline. Alkaline. A


Here again the difference between the good and bad soils, lying
such close proximity to each other, is in the content of caloit
carbonate.
SOIL SURVEY VI.

Plantation of Arturo S. Jimenez (Plantage del Rio) about 3 id
west of Bayamon: Of about 2 acres of red Spanish pineapples plant
here 90 per cent had lost their color within 12 months. Six month
later the remaining 10 per cent became colorless and the plants a.
removed. The planting was located a mile or more distant fronti
sea on a loose, sandy soil that contained many shell partly
Bananas and native corn were growing fairly well here. Previd
to planting with pineapples a good crop of tobacco had been taM
from this field. Samples 183 and 185 were taken from two differ
parts of the field by the writer; No. 156, from the same field,,
taken by a neighboring planter. No. 157 is a sample from a n4W
healthy planting and was taken by the owner.
[Bull. 11]....






13

Analyses of pineapple soils.


No. 183 No. 185 No. 156 No. 157
Soil constituents and reaction. (plants (plants (plants (plants
chlorotic). chlorotic). chlorotic). healthy).

Per cent. Per cent. Per cent. Per cent.
Insoluble matter ....................................... 70.26 73.07 67.15 82.13
Potash (K O)........... .................... ....... .13 .12 ............ .10
Lime(CaO)............................................ 10.47 8.27 11.42 2.01
Magnesia (MgO) ....................................... .74 1.12 1.17 .21
Ferric and aluminic oxids (Fe2Os and AlOs) ........... 7.58 7.42 9.57 8.77
Phosphorus pentoxid (P2Oa).......................... .18 .21 .07 .29
Volatile matter....................................... 11.35 10.18 12.41 7.33
Total...................... ..... .................. 100.71 100.39 ........... 100.85
Nitrogen (N)........................................ .11 .11 .16 .21
Moisture.......................... .................... 4.60 1.89 1.95 5.44
Carbon dioxid (CO)...................... ........... 7.15 5.18 6.66 None.
Calcium carbonate (CaCOa)............................ 16.27 11.78 15.15 None.
Reaction to litmus................................ Alkaline. Alkaline. Alkaline. Alkaline.


The three soils producing chlorotic plants are very similar to the
soils in Survey III and are strongly calcareous, while the good soil
(No. 157) differs only in containing no calcium carbonate.

SOIL SURVEY VII.

Plantation of Golden Fruit Co., about 3 miles from Bayam6n: At
various times about 40 acres were planted with Red Spanish pine-
apples. About half the acreage produced remarkably large plants
that bore a good crop of large-sized fruit. Most of the plants were
fertilized with a complete commercial fertilizer and a few received
some -barnyard manure. The soil of these fields was a loose, loamy
sand with considerable organic matter and is represented by samples
186 and 187.
Another field of about 20 acres was planted in the fall of 1909. A
year later about 50 per cent of the plants had lost most of their green
color and many had died. The 50 per cent that were unaffected
were of normal dark green and were distributed in irregular patches
throughout the field. The soil in this case was a loose sand that in
spots contained many shell particles. Sample 229 was taken from
a patch of colorless plants and 230 from an area a few yards distant,
where the plants were green. It was observed that wherever in the
field the soil contained many shell particles the plants were chlorotic
and where these particles were absent the plants were green. The
soil also was tested in many places with acid, and wherever the
chlorotic plants were found the effervescence showed the presence of
carbonate of lime, while wherever the green plants were found there
was no effervescence.
[Bull. 11]










No 231 No. 186e N.1 Wa
lt opnsulltmts and reau"on. plantsa plantsa il-P tm gC|ii
.l.tio), bel. ,.
Per cent. Per ent. Per cen. Perct.
InaMikle matter ..................... ...79.4 .7.01 3t 80. ,
otash (aO) ........................ ... ......... .I12 .t1 :.
me ( ................................ 2.45 426' ,97. sW
Magnesia (MgO)...-......-.- ...--.- TEa. .17 Trase. .
Ferric and aluminic odds (Fe aO, d sd'
AlOs ) ....................... ....... ........ 9.20 9. LtA
Phosphorus peaXtoxid (PO)--.............. .17 .12 .4 t :.
Volatile matter .................. .... 7.85 7.42 7.19 ..


Total................................


....... ..... 10059 99.161
I *I


Nitrogen (N).............................. .20 .20 .20 .U .
Moiture.................................... 230 1.93 6.77 L S
Carbon dioxide (00) ....................... .82 .2A .00 lW I
Calcium carbonate (CaCO)................ 1.86 .57 .B 1 -i
Reaction to itimna...-.................... Alkaline. Alkaline.. Alk ne. Alk i

Soil No. 186, producing fiew plats, fontaiQt :sm~c e, b la4l
small amrouint of carbonate of lime, No. 187, a god 4..
no carbonate of lime, Na. 230, aljs good, contains zU cAr
lime, whereas Nos. 229 and 231, the bad soils, contain much c

SOIL SURVEY VIII.

Plantation of Sucesores de Frontera, to .thbe north of .)jay.
playa: About 2 acres were planted with Cahezona pmeapple s~p
coconut grove bordering the shore. The soil was a loose sani.
so low that the drainage was poor. About 30 per cent of the
grew to maturity and bore fruit. The leaves of these plants w
green, but narrow and spiky. Many of the other plants died .or
light green and yellow leaves; there were only a few ivo0ry-wW
plants. The drainage being poor and the plants not well caWe f q
no conclusion could fairly be drawn from this case alono. Ne ,
is a sample froi this field. '
On the south side of Mayaguez Bay there are numerous plant
of Red Spanish and Cabezona pineapples in 2 and 4 acre patc
No examples of chlorotic plants were found there. Considering
most of the fields are unfertilized the plants have doie ftairyil
The soil is sandy, but ofa different character and origin from tet
the opposite side of the bay; No. 232 is a sample, The spil It
south is apparently an alluviql deposit and very old, conwtaii .
calcium carbonate, while the soil on the opposite shore, whlermp
chlorotic plants were found, contains many coral and .shefl pri
and was recently built up by the sea. .,1
[Bull. 11] .
.7 ;i 7 ...<





15


Analyses of pineapple soils.


No. 232 No. 233
Soil constituents and reaction. (plants (plants
healthy). chlorotic).

Per cent. Per cent.
Insoluble matter ............................................................... 63.40 77.64
Potash (K O) .................................................................. .09 .10
L m (CaO) .................................................................... 2.44 5.00
Magnesia (MgO) ............................................................... 5.67 Trace.
Feftic and aluminic oxids (FesOs and AlsO) ................................... 18.86 8.05
Phosphorus pentoxid (PsOs).................................................... .09 .15
Volatile matter................................. .................. .............. 7.11 8.45
Total................................................. ................. 97.66 99.69
Nitrogen (N).................................................................. .06 .12
Moisture ............................. .................................. 1.59 9.95
Carbon dioxide (COs).......... .......................................... ....... None. 1.45
Calcium carbonate (CaCOa)................................................... None. 3.30
R elation to litmus............................................................ Neutral. Alkaline.

Here again we find the good soil devoid of calcium carbonate,
while the bad soil is calcareous and poorly drained.

SOIL SURVEY IX.

Near the road from Rio Piedras to Carolina there are several
patches of pineapples showing the characteristic chlorosis. The
size of these spots varies from an acre to 200 plants, and they occur
on four different plantations. As they are all similar, they will be
considered together. The soil on both sides of the road is for the
most part a silicious sand well suited for pineapples, as is evidenced
by the large acreage and the uniform success of the plantings.
Directly bordering on the road, however, some patches of yellow
and white plants were observed. The soil in these spots when tested
with acid effervesced strongly, showing the presence of much car-
bonate of lime. The soil in the immediate neighborhood, where
healthy plants were found, gave no effervescence. A large number
of spots in the different fields where healthy plants were growing
were tested, and in no case was carbonate of lime present.
The road on which these plantations border is constructed of lime-
stone rock. In the construction and maintenance of this road
limestone rock was piled in the fields alongside and there pulverized.
During the pulverization much carbonate of lime was incorporated
in the soil. It seems that this is the origin of such small areas of
calcareous soil as occur in the silicious sand.
Messrs. De Sola and Wolf, at kilometer 9, have about an acre of
chlorotic plants. Samples 204 and 205 were taken from the bleached
area and samples 207 and 208 from adjacent green areas. The
plants in the bleached area are exposed to the effect of more car-
bonate of lime than appears from the soil analyses, since the drainage
water from the road runs down over this spot.
[Bull. 11]

























Mr. Coil y Cuchi, at kilometer 5, has a small patch of about..
chlorotic plants. No. 299 was taken from such a patch and No .i S
from an area of healthy plants about 5 yards distant. The 1.4.
there being higher than the road the plants are not exposed to d
age from its surface. .
In Mr. Hubbard's plantation, at kilometer 4, there are above L
white plants in a hollow below the road. No. 294 is -the soiil 2
this patch and No. 297 is a sample taken from a patch of hIrn
green plants 10 yards distant.
Mr. Gillies's plantation, at kilometer 3, has about one-tentAh:
of strongly chlorotic plants in a hollow below the road. JY X rer
to planting powdered rock from the road had been thrown on il
spot. No. 295 is the soil from this bleached spot and No. 298 i
from a healthy patch of plants 6 yards distant. While in .som.
these cases the plants were exposed to water from the road,, 3iIl
case were the plants suffering from poor drainage. :i

Analyses of pineapple soils.

No. 299 No. 296 No. 294 No. 297 No. 5 N i
oil constituents and reaction. (plants (plants (plants (plants plantl
ci-orotic). healthy). chlorotic). healthy). dhorotb ). h f i.

Per cent. Per ent. Per cent. Per cet. Per cent. .Pi n
Insoluble matter ............. 76.70 84.47 75.43 91.56 80 04 : "
Potash (KO) ................. .04 .08 .06 .09 .08 i
Lime(CaO) ................. 4.18 .29 7.55 .25 2.8
Magnesia (MgO).............. .05 Trace. .14 Trace. .10
Ferric and aluminic oxids
(FeOa and AlOa)........... 8.5 8.5 5.3 4.16 .6 .. 0I
Phosphorus pentoxid(PO).. .04 .05 .05 .01 .04
volatile mate.............. 9.98 7.01 11.15 I 4.0 16 ,ii


Total ..................
Nitrogen (N)......................
Moisture.....................
Carbon dioid (CO.)........
Calcium carbonate (CaCOs) ...
Reaction to litmus...........


99.54 100.15 99.77 100.10L 10i0.7 .
1 --* .. .--- .,- .. I *i' r. M ^ J i -J


.15 .16 .15 .11 ,14
3.35 .15 3.60 2.48 Ad13
2.73 .00 470 .00 O.61
6.21 .00 10.70 .00 b.66
Alkaline. Neutral. Alkaline. Alkaline. Alkal.


[Bull. 11]







17

It can be seen that all the above soils on which chlorotic plants
were growing are calcareous or rendered so by the drainage water,
while none of the good soils contain carbonate of lime.

SOJL SURVEY X.

Samples were also taken from fields where pineapples were grow-
ing well on soils which had the same physical character as those pro-
ducing the chlorotic plants. No chlorotic plants were observed in
these fields or in the immediate vicinity. Nos. 175 and 176 are sam-
ples from Campo Alegre, 177 from Manati, 179 and 180 from Rio
Piedras.
Analyses of pineapple soils (plants healthy).


Soil constituents and reactions. No. 175.

Per cent.
Insoluble matter........................... 89.78
Potash (KO)............................ .04
Lime (CaO ............................ .14
Magnesia (MgO) ....................... Trace.
Ferric and aluminic oxids (Fe2Oa and
Al12O)...............-.-............. 5.93
Phosphorus pentoxid (P20)....-........... .04
Volatile matter.......................... 3.93
Total.................... ....... 99.86
Nitrogen (N) ......................... .09
Moisture........................---.---- 3.34
Carbon dioxide (COs).........----------------...... .00
Ca.cium carbonate (CaCO3) .............. .00
Reaction to litmus........................ Acid.


No. 177.

Per cent.
95.04
.09
.17
Trace.
1.76
.03
2.86


.05
3.15
.00
.00
Acid.


No. 179.

Percent.
89.99
.06
Trace.
Trace.
5.08
.04
4.50


.11
1.51
.00
.00
Acid.


No. 180.

Per cent.
96.25
.04
Trace.
Trace.
.70
.04
2.92


No. 176.

Per cent.
97.12
.0A
.16
Trace.
1.88
.08
1.30


99.95 99.67 99.95 100.51


.09
.59
.00
.00
Acid.


:.
.0
.00
.00
Akld.


It will be seen that these good
carbonate.


soils are


also without calcium


The results of the soil surveys are as follows:
Of the 43 samples of soil analyzed, 22 were taken from areas where
the pineapples were chlorotic and 21 from areas where they were
healthy.
The good soils contain, on an average, 0.11 per cent potash (KO0),
0.07 per cent phosphoric acid (PO,), and 0.14 per cent nitrogen (N).
The bad soils average 0.12 per cent potash (K2O), 0.10 per cent phos-.
phoric acid (P205), and 0.17 per cent nitrogen (N). Thus the soils
producing chlorotic plants average higher in nutrients than the soils
producing healthy plants.
The chief difference between the soils producing chlorotic and
healthy plants lies in the content of calcium carbonate (CaCO).
The bad oils contain from 1.86 to 79.76 per cent of calcium carbo-
nate (CaCO).' All the good soils contain less than 1.15 per cent
CaCO, and most of them no lime in the form of carbonate.

t Noam.an.20 are excepted as here the plants were exposed to the action of a greater amount of is
than appears in the soil analyses.
4ap-Bull. 11-11---



















induced by poor drainage, but says: "We have no experence 4
pines grown on a strongly calcareous soil."
The Hawaiian pineapple soils: reported by W. P Kelley2 aver
about 0.50 per cent of CaO, most of them being acid in reaction.ri
so far as reported, none of them being calcareous. Certain soils
Hawaii were found unfavorable for pineapples due' toi th' i'
tent of soluble manganese. This- is interesting in imlstratq
sensitiveness of the pineapple to the chemical character of .tf...
From numerous analyses by Miller and Hume it appe'arS .t110
good pineapple soils of Florida mainland contain no carboe;. o
line.3 T~e type of soil which produces the best pineapple .t
contains less than 0.20 per cent of CaO and about 99 .pr aMil
inasluble matter. Webber reports that "many plantatti dBi.f
been.. put out on shell land but have uniformly failed;"4 Ase.~
shells are composed of calcium carbonate, such soils would b .i
careous. .
In the cultivation of pineapples in the Florida Keys, howeq
have an apparent exception to the proposition that pin
not grow well on a calcareous soil. Rolfs describes conditions i
as follows:
Thee are islands near the coast of southern Florida. They have a eei
]nw foundation, making a rather porous substratum. In many c
i'n the ordinary sense, can not be said to ekist. IAi some i t1iidSaW i
IphtVk iso6igted to cboose the spot thit ihasreAgh decayed vegtbl6W ttb t
06'~ plA in place on tlge ceftlline rock, The 'geater part, or neikly alt ih"lt
fit.. is located~ in the small' quantity 'of decaying vegetable iatier; donseq
is soon exhausted.6
IProf. EtHe,' iake, persoaalcomnithl6lient~idy&tslit:ie ('(m~litie##idlt ^d^
tiaa8~ bl.o the 'red lands.7 These soils always overfe coral rock tad are pro~ibly d~qed f
th!y carry very little lime, the carbonate of lime seeming to have practically ali 1e14e
iohtIiA4#and hea y a'vety fiiblidesa&d*d e Ateptphhitktio*h ItSVlIAg
arte ab. thrtteroff certain sandy ands; bat they b6uot db wat-on hev b*Alack *ih il
carry a condderable percentage of lime, and they are often unilasin by 'coaoa .a.i.i..
largely earbonatfihfh"d. m .ilMaMEiite 6 elie-t1aS4kdl E&aQ hE US
f.Hwl EfterS.. Se9,-p.-5.- ...... .... .....
SU. S. Dept. Agr. Yearbook 1895, p. 273.
i*U. ept. Agr., Farmers' Bul. 140, p. 14. :. ,
[Bull. 11]






19


Miller and Hume report:
It is the custom to use no fertilizers on the Keys where this kind of soil is found
and the land becomes exhausted after yielding three or four crops of pineapples.
At the end of this time the soil is completely worn out, and little more than the bare
rock remaining it is abandoned.
The analysis of such a soil shows nearly 5 per cent of lime, 0.30 per
cent of potash, 0.95 per cent of phosphorus pentoxid, 24.55 per cent
of humus, and 2.65 per cent of nitrogen. Although this contains a
high percentage of calcium it is probable, by comparing it with the
following analyses, that none of this lime was present as carbonate.
To investigate this matter further, samples of soil were secured
from two of the Keys through the kindness of the planters. The
samples received are hardly soils in the strict sense of the word; they
are composed exclusively of leaf mold, undecomposed leaves, and
coral particles. Samples Nos. 209 and 210 were received from Mr.
T. J. Johnson, of Planter, Fla., and Nos. 214 and 219 from Mr. Edward
Gottfried, of Key Largo, Fla. No. 219 is a virgin soil and No. 214 is
from a pineapple field which is now abandoned.
Analyses of pineapple soils from Florida Keys (plants healthy).

Soil constituents and reaction. No. 209. No. 210. No. 214. No. 219.

Per cent. Per cent. Per cent. Per cent.
Insoluble matter....--.......................-----..-- 3.10 6.62 3.15 2.54
Potash (K2O)............................ .............. .23 .29 .19 .18
Lime (CaO) ........................................ 21.13 20.34 17.01 10.96
Magnesia ( gO) ....................................... .56 .69 .17 Trace.
Ferrie and aluminic oxids (FesOaAlOs)-................ 1.97 5.29 2.44 3.11
Phosphorus pentoxid (P20s) ................. ........ .40 .30 .25 .22
Volatile matter....................................... 71.83 66.92 76.99 83.20
Total......................... ............... 99.22 100.45 100.00 100.21
Nitrogen (N).............. ................. ........ 1.89 1.97 2.41 2.61
Moisture .......................................... 19.84 20.05 13.60 19.59
Carbon dioxid (COs).................................. 11 05 9.18 7.59 1.90
Calcium carbonate (CaCOa) .......................... 25.14 20.88 17.27 4.32
Reaction to litmus .................................... Alkaline. Alkaline. Alkaline. Alkaline.

It will be seen that these "soils" are remarkable for their great
content of organic matter (as is shown by the high percentages of
volatile matter and nitrogen) and for their richness in plant food,
which must be present in a form that is quickly available to the plants.
The content of lime is high, and while a large part is combined with
the humus there is still a high percentage of calcium carbonate. It
is then evident that pineapples will stand a large amount of calcium
carbonate in the medium in which they grow providing a very large
amount of organic matter and humus is also present.
The soil surveys of Porto Rico and the information obtainable from
Cuba, Hawaii, Queensland, and the Florida mainland, concur in
showing many cases of the failure of pineapples on calcareous soils
1 Loc. cit.
[BulL 11]

















Previous to this, however, certain preliminary experiments *W!
made to show whether or not the trouble was to be attributed to 0
character of the soil, and also to explain certain apparent excepEtiom .
that occurred in the field. These experiments are here given in brit:::i
On Mr. Noble's plantation (see p. 8) some isolated patches of f go r .'..
plants were observed in the midst of chlorotic areas. It was d ei..c:i
ble to see whether these patches of plants remained green d4 i i.
differences in the soil or to individual variations in the plants the "'ii
selves. Soil from such a patch of green plants together with WIt
plants themselves were shipped to the station, also the soil and plants .
from a chlorotic area. The soil from the green plants is No. 102:O,:1:
that from the chlorotic plants is No. 101 (see p. 10). These Soil!Si
were placed in pots holding 8 pounds of moisture-free soil and we'...i
fertilized abundantly from time to time. Five chlorotic plants .we :ii
placed in soil No. 101 and 5 in No. 102. Five of the garden p lan.i'
were placed in soil No. 101 and 5 in No. 102. Ten chlorotio plantE
were placed in a good garden soil free from calcium carbonate. The .
green plants in both soils 101 and 102 remained green for some trime .I
but as their growth increased they later became chlorotic. hii
chlorosis appeared as rapidly in soil 101 as in soil 102... All ~:i
chlorotic plants placed in soils 101 and 102 remained chlorotie and .
grew but little. The chlorotic plants placed in the garden soil sooai
recovered their green color and made a good growth. Half of thes .
recovered plants were then again returned to soils 101 and 102 .and
here they again became chlorotic and growth ceased.
It is apparent from this that soils 101 and 102 are practically
same, and that the occurrence of green plants on one of them ,was ~, i~
to the fact that the slips planted there were of greater vigor than~ tfa,.
others. Field results confirmed this view, as later the isolated.:g:
plants on this plantation lost their color. The fact that ochlo
plants recovered in the good garden.soil and again..became c.hl ip4
on returning to the original soil shows that -the chlorosis wt. pr i
bly induced by the soil and is not an organic disease..:
The following experiments .-and the success of the transplaniite.',
plants on Mr. Noble's plantation (see p. 8) confirm this. .. ,,
[Bull. 11]




21


ISoil and chlorotic plants were secured from Luquillo (see p. 9).
The soil was placed in pots and well fertilized. Five chlorotic plants
were placed in the original soil; these remained chlorotic with very
little growth. Five chlorotic plants placed in a river sand devoid of
calcium carbonate became green and made a good growth. Five
healthy slips placed in the Luquillo soil grew well for a time and then
became chlorotic.
Chlorotic plants were also secured from the plantation of Messrs.
De Sola and Wolff (see p. 15). These on being placed in pots of the
river sand became green and grew normally.
These three preliminary experiments showed plainly that the chlo-
rosis is induced by an unsuitable soil condition, probably the presence
of too much carbonate of lime.
Sandy soil was then secured from a plantation near Mayaguez
where pineapples re e growing well. The soil is No. 232 (see p. 15).
Carbonate of lime in the form of ground sea shells was added to this
soil in such amounts that different pots contained 5, 10, 13, and 17
per cent of calcium carbonate. Five equal Red Spanish slips were
planted. The check plant in the soil containing no calcium carbonate
remained green throughout the experiment, while all the other plants
became chlorotic, the chlorosis appearing first and being most intense
in those pots containing the greatest amount of lime.
Experiments were then made on a larger scale to see if the addition
of calcium carbonate to a soil would cause it to produce chlorotic
plants. The details of the experiments follow.
The plants were grown in pots that contained 40 pounds of moisture-
free soil. These were exposed in the open on tables that were pro-
tected from ants and mealy bugs. Water was supplied only a few
times in the course of the experiment, as the rainfall was sufficient
to maintain a good supply of moisture during the period. The size
of the pots and the frequent rains prevented any appreciable varia-
tions occurring in the water content of individual pots due to dif-
ferences in the transpiration of the plants. In each pot only one
plant was grown, so that practically as much soil was at the disposal
of the plant as under field conditions. The experiments were run in
series of five, that is, in every case there were five pots receiving the
same treatment.
The pots were planted with suckers obtained from healthy plants
grown on the station. Previous to planting, all slips were fumigated
with hydrocyanic-acid gas to kill any mealy bugs or other pests.
Five different sizes of slips, varying from 6 to 14 inches in length,
were used in each lot of five pots, but the slips in each lot of five were
equal to those of every other lot of five. Slips of different sizes were
used for the purpose of seeing whether the appearance of the chlorosis
was affected by the initial vigor of the slip.
[Bull. 11]

























iagneia I gu ...... t. ...... .. ". ..' .<
Ferric and alminic oxids (FeO and Al) ... .... .. ... ...
Phosphorus pentoxid (POS) ....................... ....
, oleil mattr ... ........ .. .. -... --.. ...-.-
Total..... ... ... ......... .... .... .-.. ...
Itlrog n (N)........... ......... ........., .. -.......
o u e.... ..... ....... ...........--. .. .... ........-....:- .....6
Carbon dipxid (COq .......... ......... ......... ... ..-...
Calcium carbonate CaGO). ---........................ .. ....
Reaction to litmus..... ....... .. ........
!


i*."1 .:!'
a:

*i*


..." .. .. .. ..... E
Lime was addad to these soils n the .for-
limestone used was of coraline origm and occ,
disintegrated state. The use of this mteri
A.W
imitate closely natural condition, as this n onoIe
of many fields and is of the same origin as mnch of tjIt
bonate occurring in Porto Rico calcareous spils. I.
except No. IV such a lim stone, obtained from
The analysis is given below under No. 216. In
limestone of the same kind but containing more
the analysis of wJich is given under 211.
Analyses of limestone ued in pot cl .ISi|i .
... ".... ...M .


Soil constituents.



Silica and d (iO2) ..................................................
o ea a (FO .. ................ ....................
Lime (CO O.....................................................................
Magnesium (MgO) ------- ----------------- ..--..- .- .
Loss on ignition......................................... ..............
To t l.. ........ .... ...... ......... ........ .. .. I
L=,"; 1 :"E:.


The pots were al fertilized alike from time to time. ': ".
tion was rather more liberal taa necessary i order:to:
doubt that the chlorosis as not id'~ued by lahk ..
phorus, or potash. Tankage, soium nitrte, mlha5s

' The effectiveness in the soil of caluip pand magnesu tcarbop
by D. Meyer (Landw. Jahrb., 33 (1904), p. 371). .
[Bull. 11]


..a


,:L








Bul. 11, Porto Rico Agr. Expt Station.


FIG. 1.-EFFECT OF CARBONATE OF LIME ON THE GROWTH OF PINEAPPLES.


FIG. 2.-EFFECT OF FERROUS SULPHATE ON CHLOROTIC PINEAPPLE PLANTS.


PLATE II.































i//















i/ii
illlii
ii

iill
ii
















i;;










ii
I





















I


















;'













23

iad acid phosphate were mixed with the soil in such quantities that
during the period of growth each pot received 4.1 grams of nitrogen,
3.1 grams of phosphoric acid, and 6.7 grams of potash. The ferti-
lizer was given in different applications to prevent too great a quan-
tity of soluble salts being present at one time and also because there
was probably a certain loss by leaching caused by the heavy showers.
The plants were grown for a period of 10 months, and during this
time the check plants made a growth equal or superior to that of
plants in the field. A record was kept of each plant in regard to the
appearance of chlorosis. After 10 months' growth the plants were
out and weighed in the green condition.
The principal purpose of the experiments was qualitative-to
observe the effect of calcium carbonate in producing a chlorotic
appearance of the plants, but the comparative weights show in a
general way the condition of the plants and give an idea of its effect
on the growth. Accurate quantitative data of small differences in
growth can not be obtained in pot experiments with pineapples, as
it is impracticable to grow enough individuals to secure a fair average.
In experiment I the sandy soil No. 213 was used and the limestone
No. 216. The five check pots contained no lime; the other lots of
five pots each contained, respectively, 10, 20, 30, 40, and 50 per cent
of calcium carbonate. Suckers of Red Spanish pineapples were
planted. In the next table are given the appearance of the plants at
four, six, and nine months, and the average green weight.
The object of the experiment was to see whether the addition of
calcium carbonate to a good sandy soil would cause it to produce
chlorotic plants. By consulting the table it will be seen that all the
check plants made a good growth and remained dark green during
the 10 months; that all the plants in pots containing carbonate of
lime showed varying degrees of chlorosis and a great depression in
growth; that the chlorosis was most intense in the pots containing
the greatest amount of lime. (P1. II, fig. 1.)

Results of experiment in which calcium carbonate was added to sandy soil.

Average
green
Amount of weight of 5
Q o in soil. Appearance of plants during growth. plants t.5
end of 10
months,

Grams.
J ......... All plants dark green throughout the experiment........................... 1,022
10 p'ecent..... Color of all 5 plants lighter than check at fourth month; at sixth month 2 p96
plants slightly chlorotic; at ninth month all slightly chlorotic.
l0percent..... At fourth month 2 plants slightly chlorotic, others light green; at sixth 584
month all slightly chlorotic; at ninth month all 5 chlorotic.
30 per cent..... At fourth month all 5 plants light green; at sixth month 4 plants chlorotic; 623
at ninth month all chlorotic and 3 very strongly.
4B.er cent.... At fourth month 4 plants slightly chlorotic and 1 plant light green; at sixth 549
month all chlorotic; at ninth month all 5 strongly chlorotic.
liper cent.... At fourth month all slightly chlorotic; at sixth month allchlorotic; at ninth 400
month all 5 strongly chlorotic.
[Bull. 11]






















intense a chlorosis in the clay soil as in the sand, though the : .4
made a greater growth.

Results of experiment in which calcium carbonate was added to loamy soil. .
___________________________________HI


Amiont of
OCaOsinsoin.


Cheek----- -I


Cheek..........
10 per cent....

SWper cent ..-.

30 per cent ....
40 per cent.....

So pr cent .. ,


Appearance of plants during growth.


All plants dark green throughout the experiment............... ......
Color of 2 plants lighter than check at fourth month; at sixth month 2 plants
slightly chlorotic; at ninth month 1 plant chlorotie, 4 plants infatir to
check in color.
Three plants showed symptoms ofchlorosisat fourth month; at sixth month
3 plants chlorotic, 1 slightly affected; at ninth month 3 plants chlorotie,
2 slightlyaffected.
Color of 5 plants lighter than check at fourth month; at sixth month 3 chlorotic
at center, 1 slightly chlorotic; at ninth month all 5 plants chlorotic .
At fourth month 1 plant strongly chlorotic, 2 plants color equal to check, 2
plants color lighter than check; at sixth month all 5 plants oblarrati; at
ninth month all plants strongly chlorotic.
At fourth month 1 plant slightly chlorotic, 4 plants color lighter than check;
at sixth month all 5 plants chlorotic; at ninth month all plants strongly
chlorotic.


Experiment III is the same as experiment I throughout, exc "
that the soil rich in humus (No. 222) was used. The results a. .
given in the table following.
The object of this experiment was to see whether the addition of
calcium carbonate to a soil exceptionally rich in organic matter would
cause it to produce chlorotic plants. Briefly the results were: Tke
check plants maintained a good color and made an exceptional growth;
the plants in the pots with 10 to 30 per cent of calcium carbonate were
practically equal to the checks in color and growth; three plants in the
pots with 40 per cent calcium carbonate showed chlorosis at the sixth
month but recovered later, the growth being about equal to the checks;
the five plants in the pots with 50 per cent calcium carbonate weoi
slightly chlorotic at six months but all except one recovered theIi
green color later. The results of this experiment are in harmony with
the conditions obtaining in the Florida Keys. They show that th
tendency of calcium carbonate to cause chlorosis is counteracted b
[Bull. 11]


4"
iQ S;l


:: l~. 4l


::..







25


a large amount of organic matter, but that when the proportion of
organic matter to calcium carbonate falls below a certain point chlo-
rosis is produced in spite of the large amount of humus.

Results of experiment in which calcium carbonate was added to a soil rich in humus.


Amount of
aCOz in soil.


Chetck........
10 per cent.....
l0 per cent...
30 per cent.....
40 per cent ....

50 per cent.....


Appearance of plants during growth.


All plants dark green throughout the experiment.........................
All plants equal to check in color throughout the experiment ................
..... do. ... ........................... ....... ............................
.....do.............................. ............. .........................
At fourth month color of all plants equal to check; at sixth month 2 plants
chlorotic and 1 slightly chlorotic; at ninth month 1 plant slightly chlorotic,
others equal to check.
At fourth month color of all plants equal to check at sixth month all plants
strongly chlorotic; at ninth month 1 plant chlorotic, 4 very slightly chlo-
rotic.


Average
green
weight of 5
, plants at
end of 10
months.

Grams.


1,137
812
1,048
1,117
1,006


1,070


Experiment IV is the same as experiment I throughout, except
that the magnesia limestone (No. 211) was used, instead of No. 216.
As but 75 pounds of this limestone was available, only the effect of
soils containing 10 and 30 per cent of the combined carbonates (of
lime and magnesia) was tried. The results are given in the table
below.
The object of this experiment was to see if increasing the available
magnesium in the soil would lessen the chlorosis. The results were:
The check plants maintained a good green growth; the plants in all
the pots with the magnesium limestone became chlorotic; the chlo-
rosis was fully as intense as in the parallel experiment with the lime-
stone low in magnesia (experiment I). It is apparent that increasing
the ratio of magnesium carbonate to calcium carbonate from 1:51 to
1: 9 has no beneficial effect in diminishing the chlorosis or increasing
the growth of the plants.

Results of experiment in which limestone containing 10 per cent of magnesium carbonate
was added to sandy soil.


Amount of Average
combined car- green
bonate (lime Appearance of plants during growth. weight of 5
in sia) plants at
end of 10
months.

Grams.
Chek.......... All plants dark green throughout the experiment........................... 653
10 per cent..... At fourth month color of all plants poorer than the check; at sixth month 1 508
plant dead, 2 plants slightly chlorotic; at ninth month all plants slightly
chlorotic.
3 per cent..... At fourth month 1 plant chlorotic, 4 plants color inferior to check; at sixth 358
month I plant strongly chlorotic, 4 plants very slightly chlorotic; at ninth
month all intensely chlorotic.

[Bull. 114


c~---------l













soil. One plat was made up of a loamy sol contaaing no carbonate
of lime. The other three plats contained respectively 10: :Si J:. M!'
25 per cent, and 50 per cent of calcium carbonate. The lim e i:te iI
used was No. 216 and was very thoroughly mixed with the soil.
each plat 16 Red Spanish slips were planted. The plants were
growing under perfectly natural conditions of moisture, tempii
and root space.
All the plants in the check plat, with no carbonate of lime, made a.:
good green growth throughout the experiments. Te plants min *i
plat with 10 per cent of calcium carbonate at the end of five months
were distinctly inferior in color, being a very light green. At :
end of seven months 11 -plants, which had made .a fair growth,, re.
strongly chlorotic; the remaining 5 plants, wmich ..ha4 grown thd
little, were only slightly chlorotic. At the tenth mon* they .t W a
all slightly chlorotic. The plants in the third plat, with i5 2 pr aat
of calcium carbonate, were slightly chlorotic at the fifth month. A
the seventh month the 12 plants which had made a fair growths i(
very strongly chlorotic, being creamy white in color, M'ile
remaining 4 plants, which had made little growth, weae :i,:i|
chlorotic. At the tenth month all plants were strongly chlaoroty
The plants in the fourth plat, with 50 per cent of. calium carbona4 .l
were slightly chlorotic at the fifth month, and at the savanth moa&~o
the 7 largest plants were creamy white, the usmaining 9 plant. 4 ,
little growth were plainly though not intensely chltortic. At .
tenth month all were intensely chlorotic. At the ,end of ito a t
the plants were cut and the average green weight of the ajdnt.. wA n
as follows:
Average weight of plants.
Grams.
Check plat, no calcium carbonate ............................ 568
Plat with 10 per cent calcium carbonate.-:....................... 4 i42
Plat with 25 per cent calcium carbonate ..................... ..... 7 ;
Plat with 50 per cent calcium carbonate .......................... iSF.
The results of the experiments with plants grown in pots and ia :,
small field plats were as follows:
Plants grown on sandy and loamy soils to whih natural earboa liS
of lime was added became chlorotic. Plat# gropra i a soil i
was practically pure organic matter showed no osis ntil ::
percentage of carbonate of lime reached 50 pet cent. .i
[Bull. 11] ,






27


Limestone containing 10 per cent of magnesium carbonate pro-
duced as intense a chlorosis as a limestone containing 1 per cent of
magnesium carbonate.
The plants usually showed a slight chlorosis four or five months
after planting and at the ninth month were strongly chlorotic. In
all the experiments it was observed that the chlorosis was somewhat
dependent on the growth. Plants which grew slowly at first did not
become chlorotic as quickly as those which made a quick start.
Also, the plants originating from small slips became chlorotic much
sooner than those originating from large ones. Plants coming from
very small but vigorous slips, which made a quick growth at the
start, were the type that showed the chlorosis first and most intensely.
From these observations it would appear that the chlorosis was
dependent either on the exhaustion of a nutrient stored in the slip,
which the plant was later unable to obtain from the calcareous soil,
or on the absorption of an injurious amount of an element from the
soil.
CONCLUSIONS FROM SOIL INVESTIGATIONS.
The results of the culture experiments confirm the conclusions
arrived at by the soil survey. It is evident that the chlorosis of the
pineapples observed on certain plantations is caused by an excessive
amount of calcium carbonate in the soil. Experiments show that
additions of calcium carbonate to soils that produce healthy plants
cause these soils to produce chlorotic plants. Soils unusually rich
in humus and organic matter require a large amount of carbonate of
lime to cause them to produce chlorotic plants. Soils of this latter
type do not exist in Porto Rico to our present knowledge.
No attempt was made to find by pot experiments the smallest
amount of calcium carbonate in soils that would cause this chlorosis,
since the analyses of the' different pineapple soils found actually pro-
ducing chlorotic plants show this more accurately than could be
determined by pot experiments. In reviewing the analyses it will be
seen that the highest content of calcium carbonate found in any soil
producing healthy plants was 1.15 per cent. The lowest content of
calcium carbonate found in any of the soils producing chlorotic
plants was about 2 per cent. This was a loose sandy soil. Thus, for
sandy soils, a content of 2 per cent of calcium carbonate renders them
unfit for pineapples. Possibly a sandy soil containing 2 per cent of
carbonate of lime and at the same time a good content of humus
might produce healthy plants, but in general it can be safely said that
sandy soils containing 2 per cent or more of calcium carbonate are
unfitted for pineapples. The danger limit for loamy soils may be a
trifle higher. The only loamy soil which was found producing
chlorotic plants contained 4.62 per cent of calcium carbonate.
[Bull. 11]


























improvement in the plants. For- most of these caleareou" ii .:
however, it is impracticable to raise the humus content sufi $.at .
high to render them suitable for pineapples. Probably heaby: ,p4 ;
cations of barnyard manure or other organic matter to soils c~o ta .,i
ing but 2 per cent of calcium carbonate would much improve $q .
condition of the plants.
In the following pages is described another means of ovoerqmn '
the disturbances in the plant associated with the chlorosis, and :f
restoring the normal green (chlorophyll) to the leaves. Neverthel. a ,
it is improbable that this treatment will be commercially success
In the present condition of the pineapple industry in Porto RI9,
where there are still large unplanted areas suitable for pineapples, i is
not advisable to plant on soils which require extra, and fairly.: ep- n
sive, treatment to produce a crop. It is better to abandon the plant
wings of pineapples on these- calcareous soils and put in crops whkih
are adapted to this type of soil.
The calcareous sands near the sea are well adapted to oconata.
On the sandy soils which do not contain an excessive amount of 4a.-
bonate of lime, gandules and citrus trees are found growing wOA.
Tobacco does well on the calcareous soils which are not too near the
sea. It is advisable to plant these calcareous soils to one of the abve....
crops rather than to pineapples which will require extra treatmIent
to yield a crop. .
[Bull. 11]
". .
i





29


INVESTIGATIONS OF THE CHLOROSIS.

PREVIOUS WORK ON LIME-INDUCED CHLOROSIS.

Although it has never before been shown that pineapples are
intolerant of calcium carbonate and that chlorosis is induced in this
plant by the excessive amount of lime, it has been observed that many
other species of plants growing on calcareous soils show chlorosis.
The amount of lime that plants will tolerate varies greatly with the
different species and also with the different varieties of the same
species. The chlorosis of grapevines on certain marly soils of France
and Germany is probably the best known example of lime-induced
chlorosis. Some American phyloxera-resistant stocks show chlorosis
on soils containing as little as 5 per cent of carbonate of lime; other
American stocks are much more resistant, while certain native French
stocks and hybrids show no chlorosis on soils containing 50 to 70 per
cent of lime carbonate.1
Yellow and blue lupines and seradella are very sensitive to lime,
only tolerating about 2 per cent of calcium carbonate in the soil, and
their growth is greatly depressed in soils containing as little as 1 per
cent." The varieties of lupines, Lupinus mutabilis, L. albus and L.
nanus, however, are lime-loving plants and resist even 30 per cent of
lime carbonate.3
A chlorosis of pear trees growing on a strongly calcareous soil of the
Isle of Sainte-Anne is reported by Dauthenay.4 In Hertfordshire,
England, an orchard of various fruit trees planted on a soil overlying
a chalk formation was strongly affected with chlorosis. The surface
soil contained 13.53 per cent of lime carbonate. Pears, peaches,
plums, nectarines, apricots, and cherries were among the trees
affected.5 Hilgard reports a chlorosis of citrus trees growing on a
marly subsoil containing 22 to 39 per cent of lime carbonate.6
The chlorosis of many ornamental and uncultivated plants growing
on calcareous soils has also been observed. Sachs 7 reports the
chlorosis of a large number of plants growing in the garden of the
Botanical Institute in Wiirzburg. The soil of this garden he de-
scribes as strongly calcareous.
Aside from the observations of the chlorosis of plants on calcareous
soils there is an extensive literature on the adaptability of various
plants to calcareous soils.
I The amount of lime that the different varieties of grapevines will tolerate is given by J. M. Guillon and
O.Brunaud. Rev. Vit., 20 (1903), p. 535.
I Landw. Jahrb., 30 (1901), Sup. 2, p. 61. a
SJ. A. C. Roux. Trait6 des Rapports des Plantes avec le sol et de la Chlorose Vd4gtale. Montpellier andc
Paris, 1900, p. 132.
4 H. Dauthenay. Rev. Hort. [Paris], 73 (1901), p. 50.
6R. L. Castle. Gard. Chron., 3. ser., 25 (1899), No. 652, p. 405; 26 (1899), No. 653, p. 4.
SCalifornia Sta. Circ. 27.
' J. Sachs. Arb. Bot. Inst. Wirsburg, 3 (1888), p. 433.
[Bull. 11]

















plants become green. MUM later iAeiN* tretsSW mU cEtWlm
plants successfully with ferroas sulphlat#. A giwt deaV i j |
been done in France and Geraat y on the tMttnfitfbmf It
grapevines with ferrous sulphate and othEt coiJpoi~rdi s it
These treatments where they have not complIjt6ly di~ty rt ed i'thii
green to the leaves have narkedly dimin shuihid th cht.d db~dii9i i
has restored the green color to chlorotic lupinds gr~fFowiig bli !
calcareous soil.
That the effectiveness of the ferrous sulph&6t ia tf5triAbi :ii
chlorosis is due merely to the iron was well shotrf by GL~$Ib I wU
treated chlorotic grapevines with ferrous sulphtte, sthftj ic i
sodium sulphate, and with the tannate, malate, and eft e fltCj'
Only the iron compounds were effective. Hiltner' if: tl
manner confirmed this in his treatment of lupines. '
The opinion of those who have treated successfully thfi i4t1& ;
plants with ferrous sulphate and ferric cMhlod is, i" g6firl' k t
the chlorosis of the plants is caused by .lace of irtn il th lijiApI; 1
plant being unable to take up the necessary anricti of iti(~s tc '
carious soils. However, comparative analyst mide 69 dh eId fW
and green leaves and wood of the grapevine by Sehf$l si- e*Sk
the healthy plant contains muih mot' potAsli thbi thMei tl.Wfl W2
Mach and Kurmann'o obtained similar resultS. Other tiM&e,
including Sorauer" and Euler,1 have the opinion that th'hfftRbl6 bk
is largely induced by a lack of potash.
' E. W. Hilgard. Soils. New York, 1906. Proc. Soo. Prom. Agr. Sci., 7 (1886), p. 32; Forsch. Get .
Agr. Phys., 10 (1888), p. 185.
SH.Hoffmann. Landw.Vers.Stat.,13(1871), p. 269. i
B R. Braungart. Jour. Landw., 28 (1880), p. 155.
$ J. A. C. Rodx. Trait6 de Rajppor~ t des Plahtes:a ie lel et dela i cdbrM6 V6ie.: Vdie: $1giW
SParis, 1900.
SLoc. cit.... ... ....
SLuedecke. Ztschr. Landw. Ver. Grossherogtlhums He sen, 62(1892), No.41, p.33; SP (18), t 4,i.
A. Bernard, Prog. Agr. et Vit., 18 (1892), pp. 36-42. J. Guillon, Prog.Agr. et Vit., 32 (1896), pp.n86a4i
A. Menudjr, Jour. Agr. Prat., 60 (1896), II, pp. 157, 158. J. Dufour, Ber. Schwe. Bot. GesilL, 1i, &i i|
2, pp. 44.-6.
SL. iltner. Prakt. Bl. Pflanzenbau u. Pflasenschutz, n. ser., 7 (1909), Nos. 2, 3, 5.
SJ. M. Guillon. Prog. Agr. et Vit., 23 (1895), p. 663. ,
* E. Bohulze. CentbL Agr. Chem., 2 (1872), p 99.
t CentbL Agr. Chem., 1877, p. 58. .
u Paul Sorauer. Handbuch der Pfianzenklrasnkhita,Berlin, t1909 ertL v IiS Q, Ow.... ...
SH. Euler. Grundlagen und Ergelmisse der Pflanmaheni e. Braunscthwg, 100, pt. p. )S. .
[Bull. 11]




31


Hollrung is of the opinion that the alkalinity of calcareous soils
is one of the principal causes of the chlorosis of grapevines, as they
seen to grow best on slightly acid soils. Molz 2 is of the opinion that
the chlorosis of grapes is largely caused by the physical condition of
the soil.
From the previous work on chlorosis it is then apparent that certain
plants growing on calcareous soils become chlorotic, and that treat-
ment with certain iron salts is more or less effective in ameliorating
the chlorotic condition. As to just how the carbonate of lime acts in
causing the chlorosis there is some difference of opinion.
To ascertain if possible how the lime disturbs the physiology of
pineapples and induces the chlorosis the following investigations
were made.
EFFECT OF SOIL ALKALINITY AND ASSIMILABLE LIME IN
CAUSING CHLOROSIS.
Chemically calcareous soils differ chiefly from ordinary soils in
having an alkaline reaction and in containing a large amount of easily
assimilable lime. If the mere alkalinity of the calcareous soils were
the causative feature it would be expected that soils rendered alkaline
with sodium carbonate would also produce chlorotic plants. If the
large amount of assimilable lime causes the chlorosis it would be
expected that soils treated with calcium sulphate would produce
chlorotic plants. To determine whether the chlorosis is caused
either by the alkalinity or the large amount of assimilable lime, pot
experiments were carried out.
The experiments were carried out after the manner described on
page 21 except that the pots receiving sodium carbonate were kept
in the glass house to prevent loss of the alkali by leaching.
In the experiment with sodium carbonate the soil used was No.
213. Five check pots received nothing, five received sufficient
anhydrous sodium carbonate to give the soil a content of 0.01 per cent,
five received sodium carbonate to 0.05 per cent, and five sodium
carbonate to 0.10 per cent of the weight of soil. The condition of the
plants at the end of 10 months is given in the following table:
Results of experiment in which sodium carbonate was added to sandy soil.

Average
green
Cmitent ol weight o 5
NaCte, soiL Appearance of plants. rights oft
end of 10
months.

GratMs.
Cheok.......... Allplants dark green and vigorous throughout the experiment............. 700
0.01 per dent... AlrplEad drk green but stunted throughout the experiment .............. 294
0.05 per cent... ....do ... ............................................ ................. 264
0.10 pef cent... ~All slps remained ge6n with practically no growth....................... 185
I M. Hollrung. Landw. Jahrb., 37 (1908), pp. 497-616.
s E. Mols. Centbl. Bakt. [etc.], 2. Abt, 19 (1907), Nos. 13-15, p. 461; 16-18, p. 563; 21-23, p. 715; 24-25,
p. 788; 20 (1907), Nos. 1-3, p 71; 4-5, p. 126.
[Bull. 11]
































It appears that while the heavy application of gy~sdin deprssed~
the growth, like the sodium carbonate it failed to produce .ti.4
chlorosis.
Since then, it is neither the alkalinity alone nor the large a"'oun
of assimilable lime that induces the chlorosis, it would seem that t;
chlorosis is induced by both these factors working together. ;'"' t ::
factors may act directly on the plant or indirectly, by their eftfeo Ct"
some of the nutrients contained in the soil.
TREATMENT OF CHLOBOTIC PLANTS WITH IRON AND .0 ;..
SALTS. .I
A number of experiments were made to overcome the chlorosi. i;1::i
Chlorotic plants growing in pots of calcareous soil were ~trei .. s
various ways. Watering with Knop's nutrient solution was inef-
fective. This was partly to be expected, as heavy applications ...a :
nitrogen, potash, and phosphoric acid were found unavailing in ch maik.
ing the chlorosis. Additions of magnesium sulphate .to the l
intervals gave no result. If an unfavorable ratio of liae t$i
nesium were the cause of the trouble, this treatment P
proven beneficiaL .. I
[Bull. 11] I
".. ,..:;~ii~J r





33


Treatment with iron salts, however, was signally effective in
restoring the normal green color to the leaves. At first, 2 per cent
solutions of ferrous sulphate were added to the soil in which chlorotic
plants were growing without improving the condition of the plants
at all. Crystals of ferrous sulphate were then put in the soil, either
touching the roots or in their immediate vicinity. Three weeks
after the application the treated plants had improved considerably
in color, one month later the treated plants were practically a normal
green and had increased considerably in growth. The untreated
chlorotic plants which served as checks remained practically white
and without growth. (Pl. II, fig. 2.)
Chlorotic plants were also treated by brushing the leaves with a
2 per cent solution of ferrous sulphate, a 2 per cent solution of ferric
chlorid, and a 2 per cent solution of sulphuric acid. The brushing
was repeated four times, at intervals of 10 days. The plants treated
with sulphuric acid showed no improvement, while those treated
with the iron salts were considerably greener two weeks after the
first brushing, and three weeks later were of a normal green. The
facts that sulphuric acid was ineffective and that ferric chlorid and
ferrous sulphate were equally effective in curing the chlorosis indi-
cate that the action is to be attributed to the iron alone and not to
the sulphate radical nor to the acidity of the salts.
One plant, the leaves of which were almost waxy white, except
for a few brown spots where decay was starting, was treated by
dropping a crystal of ferrous sulphate in the heart. The center
leaves were burnt out by the acidity of the salt, but the other leaves
became green and a vigorous green shoot was sent out.
The effectiveness of brushing with iron salts depends upon the
solution penetrating the epidermis of the leaves. Leaves which were
burnt by the strength of the solution became green much more
rapidly than uninjured leaves. Leaves which were pricked previous
to the brushing, so that the solution could penetrate readily, became
green sooner than unpricked leaves.
While the above treatments were signally effective in restoring the
normal color and growth to plants, one treatment does not suffice for
the life of the plant. Three or four months after the restoration of
the green color, or chlorophyll, the new leaves commence to show
chlorosis, and the whole plant gradually becomes chlorotic again.
A renewed treatment with iron is again effective.
To grow pineapples on strongly calcareous soils would necessitate
repeatedly spraying the plants with ferrous sulphate, as applications
of ferrous sulphate to the soil are unavailing. It is possible that on
calcareous soils, containing from 2 to 5 per cent of calcium carbonate,
an application of ferrous sulphate to the soil might be efficacious, as
[Bull. 11]


















IJLLU AWALL 1L L %4 U944 uA IU.L LJW 04u1*E 4LY JP 'U P'Wt :UI#1.4W %mW." iVWlVA IaWur 4-I
between the .sh. coatet of green and. chk t Owtt iAnl' tM
evident in what the 4disturbaene commits, A:. s wsj Ai gi.a. ld
siderably with the age of the plant, Ony plants, to .as ;e wel~P Wi
taken for the cowparative analyses, .: '* n
The analyses wwee mads aceoriing to the .eeM4iwaed4iet ,
Association of Oficial Agricultural Che t st fA-r plwnt hI. sO
two exceptions. As the content of lime in oA th.e fh i. ii''
that of phopphoric aid, no addition oaf bMaiuia cMeto ras M:;im
previous to the ignition, whieh took 1 ploae v tr .a I :.l lSowii
Check analyses were run on sanLples igited with -nftd witt : "i
cium acetate and it was found that there was no loa of- pl rt .i
acid in the ignition without ealcium acetate and tMt 4a. li.aim n all:
be determined more accurately without the acetate additiono-. % l
determination of potash was made according to the method g swWep "
KOnig1; as for the determination of potash alone in tlhes s i liM
method was more accurate. i
The plants from experiments I, II, and III (see :pp, W.S26 RiI
analyzed at the close of the experiments. As th. eoxp pne~L ns ni
run in series of five, equal samples of the dried s0ustaufatpc ftem ip"
the five plants were combined to make a composite s epl.afn i'i
analysis. The analytical results in the table below ai :thkiva4a
average of the five plants grown under like conditions.. A the p.a 1
in this table were 10 months old and the plant in each ealpe &,Mlit
had received the same amount of fertilizer. The only factor .tgiEim i
to create a difference-in the respective ashes was the a0:iiii|
calcium carbonate in the soil. .
In the table there are three series of comparative aaslylrp A~plat
grown in a sandy soil, in a loamy soil, and in a soil jic i*~. Fp.
In each series, there are three analyses--plants gown :ia" tM .
without calcium carbonate, in the soil plus 30 per c.t of 9 t e
carbonate, and in the sioi plus 50 per .eett f et cakiwasU o
J. KOnig. Me Unternuchmng lanrdwfrtslthatlch tid gederbdit wtigefitSct::
ed., pp. 29,30. i
[Bull. 11]




35


The percentages of lime, magnesia, phosphoric acid, potash, and iron,
in the carbon-free ash are given and also the percentages of these
constituents and nitrogen in the dry substance of the plant.

Analyses of the ash of plants grown on sandy, loamy, and humus soils.
ANALYSIS OF CARBON-FREE ASH.

o5 a o 3*cn
Experiment from which CaCOa Appearance aS Vs AO
plants were taken. in soil. o leaves. OZ w '-
01 p0I

Per cent. Per ct. Per ct. Per ct. Per ct. Per ct.
None. Green....... 342 11.54 8.68 5.21 48. 22 4.65
I (sandy soil)................... 30 Chlorotic .... 343 13.00 7. 09 5.42 55.20 4.22
50 .....do....... 344 16.42 8.14 4.86 48.10 1.86
None. Green....... 345 8.80 9.60 4.64 44.28 2.74
II (loamy soil) ................. 30 Chlorotic.... 346 13. 38 7.99 4. 74 38. 62 2. 28
50 .....do....... 347 14.36 6.95 4.04 42.61 2.20
None. Green....... 337 9.76 5.60 6.49 55.94 3.62
III (soil rich in humus) ........ 30 .....do....... 338 9.80 4.89 6.65 56.95 6.87
50 Slightly 339 11.10 4.73 6.28 29.37 3.02
chlorotic.

ASH CONSTITUENTS IN DRY SUBSTANCE OF PLANT.

A c 2 -. .
Experiment from which CaCOs Appearance Uo a" P 0 0 o
plants were taken. in soil. of leaves. OZ w o ." 8 U "


Per cent. P.ct. P.ct. P. c. P. c. P.ct. P.ct. P.ct.
None. Green....... 342 6.19 0. 71 0.54 0.32 2.99 0. 29 0.67
I (sandy soil)................ 30 Chlorotic.... 343 6.43 .84 .46 .35 3.55 .27 .55
50 .....do....... 344 9.11 1.50 .74 .44 4.38 .17 .55
None. Green....... 345 5.93 .52 .57 .28 2.63 .16 .75
II (loamy soil).............. 30 Chlorotic .... 36 6.08 .81 .49 .29 2.35 .14 .58
50 .....do....... 3-7 7.45 1.07 .52 .30 3.18 .16 .60
None. Green....... 337 6.76 .66 .38 .44 3.78 .21 .72
III (soil rich in humus).... 30 .....do....... 338 6.68 .65 .33 .44 3.83 .46 .67
50 Slightly 339 -8.11 .90 .38 .51 2.38 .24 .69
chlorotic.


It will be seen that the addition of calcium carbonate to the sandy
and loamy soils, inducing chlorosis, had the effect of increasing the
percentage of lime in the plant ash and of diminishing the percentages
of iron, The percentage of magnesia as a rule diminishes, although
not with the same regularity, while the phosphoric acid shows no
regular increase or diminution. In the soil rich in humus the addi-
tion of 30 per cent of calcium carbonate had no effect upon the plant
ash, and it will be remembered that it also had no effect in inducing
the chlorosis. The addition of 50 per cent of calcium carbonate to
this soil, however, induced a slight chlorosis, and affected the plant
ash, in the same way, although to a less degree as did smaller addi-
tions of calcium carbonate to the sandy and loamy soils.
In regard to the percentages of the various mineral constituents
in the dried substance of the plant, it will be seen that wherever
chlorosis was induced the addition of calcium carbonate to the soil
[Bull. 11]


U























































Description
of plant.


Large Cabezo-
na 18 mos.
old.
olD.
Do.........
Small Cabezo-
na 18 mos.
old.
Do ........
Red Spanish,
24 mos. old.
Do ........
Red Spanish,
14 mos. old.
Do.........


Appearance
ofleaves.
',ve.


Green.......

Chlorotic....
Green ......

Chlorotic....
Green........
Chlorotic....
Green .......
Chlorotic....


S




0


Analysis of crbon-free ash.


C.


C
-B
U.,


oO



P1S


A
a
o .


P-4


Ash constituents in dry substai ,
of plant.


OM
I
C0


a
00

be


A -
a .
*a


1------- 1-I 1 1-I-- I 1- I I ~ I ~I II I t


I P. d. 1P.9 d.2
237 I 27.331 9.12


238
233a

233d
196
195
104

103


26.18
23.16

24. 00
29.40
29.45
23.37
28.17


14.19
6.70

10.38
12. 55

9.88


P. t.
5.89

8.53
8.54

5.66
4.42
3.45
4.93
3.46


P.td.. P. d.IP. d.P. dt.
33.44 1.11 6.00 1.64


'3.72

29.65
13.05
19.78
35.45
33.64


.49

.47


.438


5.833 1.40
5.81 1.35


7.70
6.28
7.10
6.56
7.81


1.84
1.85
2.09
1.53
2.20


P.ct.
0.55

.78



.87
.5 .1



.io


P. d.
0.35


P.t.



2.25

I3.28
.82
1.39

2.63


It will be seen from the table that there are no differences betwa '
the analyses of the green and chlorotic plants that are sustaina... ..
all four cases. The nitrogen content of the green and chlorotic plt. i
is in one case equal but in the other three cases in this table, as'9i
as in all the other analyses made, the chlorotic plants contain i.. ]

less nitrogen than the corresponding green plants.
[Bull. 11]
.. .....l
A~i


IF'.I


0.0I





.04
.. i
.'.
;
0J


S., -
.:g.. :ip
" .


.... ,.::- 1


mi

1..
.m "


. .. -


~~~-~-- ----


.. -.




37


Considering all the analyses together, it will be seen that the ash
of these plants grown on calcareous soils differs from the ash of plants
grown on noncalcareous soils chiefly in containing a larger amount of
lime and a smaller amount of iron.1
r While there were no differences between the chlorotic and green
plants reported in the table it should be borne in mind that the green
I plants were exceptional in that they resisted the chlorosis longer than
the average plant, also, that while these plants were green, they were
not normally developed and that this class of plants eventually
S became chlorotic (p. 36).
To see whether the large amount of lime in the ash is the sole cause
of the chlorosis analyses were made of plants which were grown on
noncalcareous soils that had received a heavy application of lime.
The plants were grown on small plats of a clay loam soil, 40 plants to
the plat. The check plat received no lime; the second plat, lime at
the rate of 3,400 pounds of calcium oxid per acre in the form of
burnt lime; and the third plat, the same amount of calcium oxid per
acre but applied in the form of gypsum and burnt lime together.
The growth of the plants in the limed plats was depressed, but none
ao the plants ever showed chlorosis. The plants were 16 months old
S when analyzed. In the following table are given the analyses of
plants from each of the three plats:

Analyses of the ash of plants grown on noncalcareous soils which had received heaty
applications of lime.

SAnalysis of carbon-free ash. Ash constituents in dry substance of
plant.
.o d
Quantity of lime ra 3a S -
per acre added ) c 0& "" Z
to soil. "- 0



P.ct. P. ct. P cft. P. t. P. t. P. t. P. t. P.c.t. P. t. P.ct.
None............ Green. 268 12.00 19.40 5.96 53.04 7.36 3.19 0.38 0.62 0.19 1.69 0.24 0.93
3,400 lbs. CaO
from CaO ........do... 267 22.32 25.25 5.99 25.68 6.33 2.78 .62 .70 .17 .71 .18 .79
3,400 lbs. CaO
from CaO and
CaSO ........ ...do... 266 27.60 20.79 6.53 27.33 2.82 3.23 .89 .67 .21 .88 .0 .92

It will be seen that the plants grown on the soils to which lime was
applied contained more lime in the ash and dried substance than the
check plant and less potash and iron. While the content of iron in
the plants grown on the limed plats is much less than that of the
check plant it is nevertheless much greater than that of the plants
reported in the preceding table (p. 36). The nitrogen is practically
the same in all three plants.
I The analyses in the above table show a higher percentage of lime and a lower percentage of iron than
any of the analyses reported by J. C. Brtinnich. Queensland Dept. Agr. Rpt. 1903-4, p. 76.
[Bull. 11]




































Untreated......... Chlorotic.. 255 30.10 9.18 3.14 37.69 0.68 5.8 1.77 0.540.18 2.21 O.0
Brushed w i t h
FeS04........... Green... 254 20.59 6.0 4.64 4&.25 1.1 5.63 1. .34 .3 3 2.0 .
Untreated......... Chlorotic.. 276 22.01 9.62 2.67 46.46 .44 6.09 1.34 .59 .10 2.25 .8
Brushed w i t h
FeS04........... Green..... 277 24.52 7.25 2.41 4.09 1.49 7.30 1. .18 3.
FeSO4 applied to : iV
roots........ ...do........ 278 28.76 9.25 2. 37.0 1.01 89 2.10 .68 .11 2.55 ,1., :
', ,.: ___

The ash of the plants turned green by ferrous sulphate differ fran
the ash of the chlorotic plants only in containing more iron. Th'u
it would seem from this table that the chlorosis is caused mer,&9 il
a lack of iron or by a lack of iron in some active form, and that :Mti
generally lower content of potash in ehlorotic plants is not the sio0 ':I.
but a result.
Considering all the facts brought out by the ash analysed, it ul~d.':i
appear that the chlorosis is induced by an increased abserlptk -tii
lime 'and a diminished absorption of iron. It is certain 'that ,a*.i
absorption of an unusual amount of lime is not alone s. .i.lt .
cause the chlorosis. It is possible that when an exressi ,ao l
of lime is absorbed by the plant that more iron is needed t r thsa'n
ordinary conditions. The work of Hiltner on lupines subumt il
this view.'
[..Bull. ..1 .. "::d|
Loo. cit. ...
[Bull. 11] ..."






39


It is not felt that this conclusion can be stated with certainty
from a consideration of the above ash analyses alone. If the chlo-
resis is caused by the combined effect of an excess of lime and a lack
of iron in the plant, it would seem that there should be a definite
ratio of lime to iron in the ash which would induce the chlorosis.
But in the above analyses no such ratio is apparent.
It is felt that analyses of other species of plants that become
chlorotic on calcareous soils are needed for confirmation, and this
work is now in progress.
The lower content of nitrogen in the chlorotic plants is probably
not the cause of the chlorosis but the result. The absorption of
nitrogen can hardly be interfered with in calcareous soils, and in all
the experiments the plants received a liberal supply of easily assimi-
lable nitrogen. Similarly it appears that the lower content of potash
found in some of the chlorotic plants of the table on page 35 is but
the result of the chlorotic condition. In this table it will be seen
that some chlorotic plants contain 38 per cent, 48 per cent, and 55
per cent of potash in the ash, quantities much greater than many
healthy plants contain. These analyses would tend to contradict
the view held by Sorauer and some others that the chlorosis on
calcareous soils is caused by a lack of available potash.
ENZYMS IN CHLOROTIC AND GREEN LEAVES.

Woods has shown 2 that under certain pathological conditions of
various plants, as in the mosaic disease of the tobacco, the attendant
chlorosis seems to be caused by the presence of an excessive amount
of the oxidizing enzyms, oxidases and peroxidases, in the leaves.
Tests were made to see whether in the chlorosis.of the pineapples the
phenomenon was accompanied or caused by a like increase in the
enzyms. For this purpose the content of normal green leaves in
oxidases and peroxidases was compared with that of chlorotic leaves.
The method employed in comparing the different amounts of
enzyms was as follows: In every case equal quantities (generally 10
grams) of the fresh leaves were triturated with sand and chloroform
water in a porcelain mortar. The solution and macerated leaves were
then made to 500 cubic centimeters with distilled water, allowed to
stand 15 hours, and passed through a dry filter. The filtrate was
used in making the comparative tests; 1, 2, 4, 6, 8, and 10 centi-
meters of these solutions were put in Nessler tubes, the volume of
each tube made to 10 cubic centimeters with distilled water and equal
quantities of neutralized hydrogen peroxid and freshly prepared
2 per cent alcoholic solution of guaiacum resin added to each tube.
At the end of 10, 15, or 20 minutes the various tubes were compared
I Loe. cit. 2 A. F. Woods. Centbl. Bakt. [etc.], 2. Abt., 5 (1899), No. 22, pp. 745-764.
[Bull. 11]




























on leaves of similar age, gave duplicate determinations. AAlJw /ap i
ples from similarly situated. leaves on different plant of the 4
age gave duplicate determinations. Samples taken from very old!
leaves differed, however, from very young ones. Alt a sam'p& I..
taken at the base of a leaf differed slightly from ond taken nearfi t.
tip of the same leaf. Therefore, in all the following tests, care .a '
used to take the samples from the same relative position on le ae
of similar age.
From preliminary tests it was apparent that the quantity of o.r .I
dases in pineapple leaves is very small in comparison with the qt ia.i .
tity of peroxidases 1 and that the quantity of oxidases varies in b I
same proportion as the peroxidases, hence tests were only mind' .;
the peroxidases.
The leaves of the plants grown in the pot experiment described on
page 21 were tested for peroxidases.2 The results are given in te
following table, in which the first column gives the soil in which tr :I
plant was grown, the second the condition of the leaves in regard ,
chlorosis, and the third the quantity of peroxidase. The quinti..li
of peroxidase in the leaves of the check plant is taken as 10 and ti
other quantities are expressed relative to this.
1 By oxidases are here meant those enzyme which blue an alcoholic gualac solution without t9~.head iI
of hydrogen peroxid, and by peroxidases, those enzyme requiring hydrogen peroxid to give the g4 a V jp
reaction.
According to Bach and Chodat and Moore and Whitley we may be dealing here with only one:
peroxidase; the blueing of guaiac solution without hydrogen peroxid being due to a peroxuidae pn .i
organic peroxid.
' Catalase was also tested for, but found present only in very small and apparently equal quantitleo::R ini.
the green and chlorotic leaves.
[Bull. 11]
.,,Ja:i




41

Amount of peroxide present in chlorotic plants grown on soils containing different
percentages of calcium carbonate.


The leaves of the plants grown in pot experiments I, II, and IV
(see pp. 23-25) were also tested for peroxidases. In these cases leaves
were taken from two check plants, one from the largest and one from
the smallest of the five grown. The results are given in the table
below, the arrangement of which is the same as the preceding table.

Amount of peroxidose present in chlorotic plants grown on soils containing different
percentages of calcium carbonate.

Plants from Experiment I. Plants from Experiment II. Plants from Experiment IV.

Compar- Compar- Compar-
ative native ative
11o.0 Appearane amount CaCOa Appearance amount CaC03 Appearance amount
I s of leaves. of in soil. of leaves, of in soil. of leaves, of
peroxi- peroxi- peroxi-
dase. dase. dase.

Per cet. Per cent. Per cent.
None. Green....... 10 None. Green....... 10 None. Green....... 10
NSeh. .....doa ..... 10 None. .....do....... 10 None. .....do...... 10
20 Chlorotic.... 2.5 20 Chlorotic... 5 10 Chlorotic.... 6.6
0 ....do ....... 6.6 40 .....do...... 8 30 .....do....... 6
40 .....do..... 3.7 50 .....do....... 4.5 30 .....do....... 7
S ... ....... 3 .......... ............ ............ ............ ..........


In the next table is given the peroxidase found in a chlorotic plant
and in two plants that were once chlorotic, but that had become green
by treatment with ferrous sulphate. The plants were all growing in a
sand containing 34 per cent of calcium carbonate, and previous to the
treatment with ferrous sulphate were equally chlorotic. It will be
seen that although one of the plants treated with iron contains much
more peroxidase than the other, they both contain more peroxidase
than the chlorotic plant.

Amount of peroxidase in treated and untreated chlorotic plants.


[Bull. 11]


Compara-
Col. Appearance of leaves. amount of
peroxidase.

Per cent.
None. Green ................. 10
5 Slightly chlorotic...... 7.5
10 .....do................ 10
13 Chlorotic.............. 8.3
17 .....do................. 5


Compara-
Tratment of plants. Appearance tive
of leaves. amount of
peroxidase.

Untreated................ Chlorotic.... 3.3
Brushed with FeSO4..."... Green....... 6.6
FeSO4 applied to roots..... .....do...... 10







The resutat of the"e determinations a *
leaves of pineapple plants contain muchm'ore' liroxidaese
leaves., It is apparent, then, that this chlrosis of'pineapples
in calcareous soils is caused -by a diffrant disturbance in Ohe
from that in those cases explaine ...d by Woods. Wood&
chlorotic leaves from many plants. Somre of. these yellow leaves
been punctured by aphids. The colorless' portions of var0e
leaves, etiolated leaves, tobacco leaves affected with mosaicdieu
and peach leaves f 0rom trees. affected with "Yellows" and rosettewa
also examined and found to contain more oxidizing enzyms thanno
mal green leaves. Although the chlorosis, or lack. of chloph r
all these cases was attended by an inifreasemin oxid~izing ezmi
evident from the above. results wth pineapples that theelrei
leaves is in some cases attended by a duiminutio'n of peroxidase.
In the light of the other work on the pineapple leaves it is probable
that this deficiency of enzyms in the chlorotic leaves has no beam'g,
on the chlorosis, but is merely the result of- the degeneration onmpp
by the excess of lime and lack of iron in, the plant. 4.
EFFECT OF LIGHT ON TE CHLOROBIS.:
it was observed in the field that plants growing under partial hA*&
seemed less chlorotic than those exposed to full sunlight. To seeit
the chlorosis could be much diminished by partial shade' a dupli-
cate of experiment I (see p. 23) was run Mi a glass house that was
heavily shaded.
The plants in the glass house showed very much less chlorosis than
those exposed in'the open. The results of this experiment are incon-
elusive., however, as the plants in the glass house did not miake half the
growth of those exposed in the open. Since the intensity, of the,
chlorosis has been seen to be more or less dependent on the amountrof
growth, the smaller degree of chlorosis in this case was prbbyduo
to the fact that little growth was made.
It was. found, however, that plants which 'had. become stroll
chlorotic. and which had long ceased to grow, became doe'iel
greener when placed under heavy shade for one or two weeks, ut
when they were again exposed to full sunlight they, shoved their-
original chlorosis within a few days.


plant.' The destruction of the chlorophyll is brought, about by strong
sunlight and increases with the intensity of the light. In the chlorosias
1 H. Euler, Grundlagent und Ergebnisse der Pfianzenchemie, Braunsehweig, IN%8 pt. 1, p. IfL T.
Czapek, Biochemie der Pflanzen, Jena, 1905, vol. 1, pp. 452, 458, 468. H. Molisch, r. DeuL BoL GesA,,
2o (1902), pp. 442-448. Molisch found that aloe leaves that became brown In dkret s~unlght becmagw




43


of pineapples in calcareous soils the plant is unable to form the chloro-
1 phyll as fast as it is destroyed by the light. When the plant is
Partially shaded, however, the balance of the reaction is shifted; the
Chlorophyll is destroyed less rapidly, though it may be formed at the
Same rate as in the sunlight, so the plants become greener.
The appearance of less chlorotic plants in shaded portions of a field
affected with chlorosis is, then, due to the fact that the plants have
made a less rapid growth at the start than the rest of the plants, and
also to the fact that the chlorophyll is destroyed less rapidly in the
Shaded plants.
CONCLUSIONS FROM INVESTIGATIONS OF THE CHLOROSIS.
In deciding as to what is the primary cause of the failure of pine-
apples on calcareous soils and of the appearance of the chlorosis, it
should be borne in mind that chlorosis is not a specific disease, but is
merely an outward manifestation that attends certain physiological
disturbances in the plant. Plants suffering from poor drainage and
from bacterial diseases and certain plants growing on calcareous soils
all show chlorosis. It should also be taken into consideration that
one disturbance in the physiology of the plant will bring on a series of
other disturbances, which are to be regarded only as attendant
phenomena.
In the above investigations it was found that pineapples, in common
with some other plants showing chlorosis on calcareous soils, were
Greatly benefited by treatment with iron salts, the iron salts over-
coming the chlorosis and inducing a normal growth.
No other treatment was found that overcame the chlorosis. It
appears, then, that the plants need iron and that they are unable to
obtain this from the soil, although there is a large percentage of iron
in some of the calcareous soils. The facts that solutions of ferrous
sulphate applied to the soil gave no result, while crystals applied to
the roots or solutions of iron applied to tLe vegetative portions of the
plant gave marked improvement as soon as they were absorbed, show
that the carbonate of lime in the soil reacts with the iron (forming
ferric carbonate) and depresses the availability of the iron for the pine-
apple plant. That all species of plants growing on calcareous soils
do not suffer to an equal degree for lack of iron is probably because of
their different abilities to take up iron. That certain species of plants
differ in their ability to take up phosphoric acid is well known.
The ash analyses support in a general way the assumption that
There is a lack of iron in the chlorotic plants and show that probably
Sthe increased absorption of lime creates a necessity for an increased
Quantity of iron. The excessive amount of lime in the plant may
render inactive the small quantity of iron absorbed.1 With our pres-
1 See also Hiltner, Loc. cit.
[Bull. 11]




































It ~eezms, then, that pineapples growing on c.tarcume o uws Si'
an excessive amount of lime and an insufficient amount of innf ofl!
as a result there is an inability to form chlorophyll and degelerlii
of the plant follows, as is shown by a decrease in the cott-A
peroxidase, nitrogen, and occasionally potash.
S" .. ...; "..;;.[::; "::! i .i .
STUXXARY.

Pot experiments and a chemical survey of. the pineapple a'so0il. i..l
Porto Rico show that the failure of pineapples, with the appear ,:
of chlorosis, on certain areas is due to an excessive amount of ur
bonate of lime in the soil.
For ordinary sandy soils about 2 per cent of calcium earbo
renders them unsuitable for pineapples; smaller amounts than .
do not appear to be injurious.
Soils composed principally of organic matter may con tain
40 per cent of calcium carbonate and still produce vigorou p
H. Mollsch. Die Pflanze in Whren Beleh~ mum Elsea. jea1, 1t i*
[Bull. 11 ] '





45


Pineapple plantings on calcareous soils should be abandoned and
the land planted to lime-loving crops.
In curing the chlorosis, fertilizers were ineffective, but treatment of
the leaves with solutions of iron salts or crystals of ferrous sulphate
applied to the roots was effective and induced a normal growth.
treatment does not appear to be commercially feasible.
S The chlorosis is not caused by an organic disease, but is the result
of a disturbance in the mineral nutrition of the plant induced by the
Scalcareous character of the soil.
i It is neither the mere alkalinity of calcareous soils nor the large
amount of assimilable lime that causes this disturbance, but the
combined action of the two properties.
The disturbance in the mineral nutrition of the plant, or the primary
cause of the chlorosis, seems to be the lack of iron in the ash or the
small amount of iron in the presence of a large amount of lime. A
S mere high percentage of lime in the ash does not induce chlorosis.
S Chlorotic leaves are lower in nitrogen and oxidizing enzyms than
green leaves, due, probably, to the degeneration induced by the lack
tit iron.
SStrong light increases the chlorosis by the more rapid destruction
of the chlorophyll.
ACKNOWLEDGMENT.
The greater part of the analytical work detailed in this bulletin was
Sprformed by Mr. W. C. Taylor.
Thanks are due to various planters who kindly sent soil and plants
necessary for the work, and to Mr. Lucas Valdivieso for 15 tons of
limestone used in the experiments.
[Bull. 11]






















































































































































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