THE INFLUENCE OF CALCIUM AND MAGNESIUM
COMPOUNDS ON PLANT GROWTH

BY

FRANK ARCHIBALD WYATT

B. S. Agricultural College of Utah, 1910

M. S. University of Illinois, 1913

THESIS

Submitted in Partial Fulfillment of the Requirements for the

Degree of

DOCTOR OF PHILOSOPHY
IN AGRONOMY

IN

THE GRADUATE SCHOOL
OF THE

UNIVERSITY OF ILLINOIS
1915

THE INFLUENCE OF CALCIUM AND MAGNESIUM
COMPOUNDS ON PLANT GROWTH

BY

FRANK ARCHIBALD WYATT
fH

B. S. Agricultural College of Utah, 1910
M. S. University of Illinois, 1913

THESIS

Submitted in Partial Fulfillment of the Requirements for the

Degree of

DOCTOR OF PHILOSOPHY"
IN AGRONOMY

IN

THE GRADUATE SCHOOL

OF THE

UNIVERSITY OF ILLINOIS
1915

A^

CONTENTS

PAGE

I NTRODUCTION - ' 585

REVIEW OF THE LITERATURE 590

EXPERIMENTAL WORK 593

Description of Procedure and Methods 594

Effect of Magnesium and Calcium in Prepared Carbonates
and in Dolomite Upon Wheat and Alfalfa Grown in Sand

(Series A and B) 596

Effects of Calcium and Magnesium in Prepared Carbonates
and in Dolomite Upon Wheat and Alfalfa in Brown Silt

Loam (Series C and D) 598

Effect of Magnesium and Calcium in Dolomite, Magnesite,
and prepared Carbonates Upon Wheat and Alfalfa in

Sand (Series E and F) '. 600

Effect of Magnesium and Calcium in Calcareous Soil, Mag-
nesite, Dolomite, and Prepared Carbonates Upon Wheat

and Alfalfa (Series G and H) 60 1

Effect of Magnesite and Dolomite Upon Wheat and Soy-
beans (Series I and J) 605

The Effect of Maximum Quantity of Calcium and Mag-
nesium Upon Wheat and Soybeans in Sand (Series K) 606

Effect of Magnesium and Calcium in Sulphates, Chlorides, '
and Carbonates Upon Wheat and Soybeans in Sand

(Series L and M) 608

Effect of Magnesium and Calcium in Calcareous Soil, Dolo-
mite, and Magnesite, After Alfalfa, Upon Soybeans

( Series N ) 6 10

DISCUSSION 613

CONCLUSIONS 615

LITERATURE CITED 6 1 6

ILLUSTRATIONS ...

UBRAKY

* OF CALIFORNIA
SAJVTA BARBARA

INFLUENCE OF -CALCIUM AND MAGNESIUM COMPOUNDS
ON PLANT GROWTH1

By F. A. WYATT,2
Assistant in Soil Fertility, Agricultural Experiment Station of the University of Illinois

INTRODUCTION

Some investigators seem to question the advisibility of using mag-
nesium-bearing minerals in agricultural practices, since they deem mag-
nesium detrimental to optimum plant growth. Magnesium in some forms
is detrimental to plant growth. However, the natural carbonates, such
as limestones and dolomites, are not detrimental but in reality beneficial
to plant growth when applied in amounts sufficient to neutralize soil
acidity. Plants were found to grow and mature normally in pure dolo-
mite and limestone.

In scientific circles considerable attention has been paid to the theory
that calcium and magnesium must occur in a definite ratio for the opti-
mum production of crops. Loew claims to have proposed this theory in
1892 (is)3, and much work has been conducted along this line, especially
during the last decade. From the data presented in the following pages
it will be seen that the ratio, within wide limits, had no effects.

The presence of sufficient quantities of calcium and magnesium in all
soils is essential for the profitable production of crops. Various forms
and quantities of these two elements may largely control the yields and
composition of the harvests.

It is a well-known fact that plants will tolerate larger amounts of an
essential element than they require. The quantity of calcium and mag-
nesium taken up by plants is dependent upon the amount available and
upon the kind of plants. The silicates of calcium and magnesium are
relatively insoluble, while the chlorids are very soluble. Dolomite is
denser and less soluble than limestone but more soluble than magnesite.
Synthetic compounds of magnesium are more soluble, however, than
similar compounds of calcium.

Alfalfa, when grown in sand and soil cultures with varying amounts of
calcium and magnesium minerals, such as dolomite and magnesite, also
with prepared compounds of these two elements, such as the chlorids,
sulphates, and carbonates, was found to contain varying amounts of

1 This paper was submitted in partial fulfillment of the requirements for the degree of Doctor of Philos-
ophy in Agronomy in the Graduate School of The University of Illinois in 1915.

2 It is with pleasure that I acknowledge my indebtedness to Prof. C. G. Hopkins, Dr. A. L. Whiting,
and Prof. J. H. Pettit for suggestions and helpful criticisms.

3 Bibliographic citations in parentheses refer to " Literature cited," p. 616-619-

Journal of Agricultural Research, Vol. VI, No. 16

Dept. of Agriculture, Washington, D. C. July 17. 1916

(589)

590 Journal of Agricultural Research vol. vi. NO. 16

calcium and magnesium. Some treatments showed as much as 52.5
pounds of calcium and 12.98 pounds of magnesium per ton of dry alfalfa.
However, the above amounts were in excess of the absolute requirements,
as smaller applications gave as large yields and the alfalfa contained only
28 pounds of calcium and 8 pounds of magnesium per ton of dry matter.
On this basis 6 tons of alfalfa with a high-calcium content would contain
315 pounds of calcium and 77.88 pounds of magnesium, or the equiva-
lent of 787.5 pounds of calcium carbonate and 272.5 pounds of magnesium
carbonate. Wheat straw, when grown in pure dolomite, contained 14.48
pounds of calcium and 14.6 pounds of magnesium per ton, whereas when
grown in the absence of excessive amounts of these two elements the
straw contained only 5.96 pounds of calcium and 5.43 pounds of magne-
sium per ton.

REVIEW OF THE LITERATURE

Solution cultures and pot cultures have contributed largely to our pres-
ent knowledge of plant nutrition. Woodward (42) found that the solid
particles of the soil furnished nourishment to the growing plants and that
water acted only as a carrier.

Wolf (4) found by using beans and maize in controlled solutions, that
the concentration as well as the kind of salts in the solution effected
plant growth. His results show that when the concentration of the
external solution was more than 0.25 per cent it became the controlling
factor; whereas if less than 0.25 per cent absorption was controlled by
the solution within the roots.

Dassonville (i) found that cutinization and lignification of the epidermis
of leaves occurred much more rapidly in distilled water than in nutrient
solutions; also that the growth of hemp and buckwheat was not influenced
by the presence or absence or calcium and magnesium.

The crop is the measure of the resultant of all factors. In accordance
with the present knowledge any one or many of the factors can be con-
trolled. Likewise, the total amounts of the elements essential for crop
production can be quantitatively determined.

Magnesium is essential for the growth of any living cell. Calcium
is likewise essential except for the lower fungi and lower algae, which
alone are able to exist without it. Loew (16, p. 44) shows that neutral
oxalates are not poisonous to the lower fungi. He attributes the dele-
terious effects in higher plants to the change in the structure of the cal-
cium-protein compounds, due to the formation of calcium oxalate, while
the disturbance is brought about by the change in imbibition caused by
the formation of potassium-protein compounds, and that magnesium
may bring about this change provided there is a deficiency in calcium.

Reed (29) found calcium to be necessary to the activity and growth of
chlorophyll-containing organs. Willstatter (40) has pursued in detail

July 17. 1916 Influence of Calcium and Magnesium on Plant Growth 591

the study of chlorophyll and finds it to be a magnesium compound with
generally three times as much green pigment as yellow pigment. He
found that the magnesium content of chlorophyll was constant in both
land and sea plants; therefore, it must function other than as a catalyzer.
Pfeffer (27, p. 425), Macdougall (17, p. 219), Peirce (26, p. 100) and
others believe magnesium and calcium play an important and necessary
function in plant synthesis and cell formation, but are unable to assign
any specific role to either of these elements.

There has been considerable contention as to whether calcium could
be replaced by other members of the group. Haselhoff (7) grew beans
and maize in solutions containing varying quantities of calcium and stron-
tium and concluded that strontium seemed to take the place of calcium,
replacing it only when the supply of calcium was inadequate. But it
must be remembered that he first used calcium and strontium together
in the solution and later reduced the calcium. However, Loew (16, p. 48)
was unable to substantiate these results when he used species of Trades-
cantia.

Loew explains the toxicity between calcium and magnesium as being
due to the formation of an insoluble condition of the phosphoric acid
being fixed by the calcium, and that the framework (15) of the nucleus
and plastids is a double organic salt of calcium and magnesium. How-
ever, Meurer (19) and Nathansohn (23) offer another explanation: Cells
being selective in their absorption of ions can check osmosis before a
balance is reached between the solution within and without the cell, and
the absorption of salts does not increase proportionally with the increase
of concentration of the outside solution. Osterhout (24) using calcium
nitrate and magnesium nitrate was unable to substantiate Loew's
assertion.

Considerable work has been done upon the antagonism of respective
salts for each other in solution. Kearney (i i, p. 20) shows that calcium
salts are most beneficial in reducing toxicity. Lipman (14) reports
toxicity between magnesium and sodium but not between magnesium
and calcium.

Numerous investigators have sought answers to the proposed theory
of a lime-magnesia ratio with just as numerous and conflicting results.
Solutions, pot cultures of soil and sand, and field soils have all been em-
ployed in attempts to settle the controversy. Ulbricht (34) showed that
yellow lupines, barley, and vetch were injured by applications of lime,
especially when it contained high percentages of magnesia. Magnesia
apparently increased the proportional yield of grain in the case of barley
and lupines. Dojarenko (2), however, concluded that the theory of a
definite calcium-magnesium ratio was not tenable, as many Russian soils
containing great excesses of calcium over magnesium were benefited by
liming.

592 Journal of Agricultural Research vol. vi, NO. 16

The results of water and soil cultures by Gossel (6) failed to substan-
tiate the theory of a definite ratio of calcium to magnesium. He obtained
the highest yields for beans and barley with water cultures when the
ratio of lime to magnesia was 0.04 to i , and concluded that the effect of
liming is dependent upon the character of the soil and not upon a definite
ratio of lime to magnesia. About this same time the Japanese inves-
tigators (22) were actively engaged with the problem. However, their
results all seem to bear out the theory of a definite ratio.

Konovalov (12), a Russian investigator, reports studies with barley,
millet, oats, and maize, varying the ratio of calcium oxid to magnesium
oxid, as follows: 13.4 to i, 6.7 to i, 3.3 to i, 0.8 to i, and 0.4 to i. He
found that the yields tended to increase with the increase of lime appli-
cation, provided the magnesia content remained constant. Notwith-
standing these results, Voelcker (35, 36, 37) states that the ratio is best
at i to i.

Meyer (20, 21) found that with buckwheat and oats the dependence
of maximum yields on a definite ratio of calcium to magnesium could
not be proved even in the case of soils containing more calcium than
magnesium or vice versa. Undoubtedly the most extensive investiga-
tions regarding a definite calcium-magnesium ratio have been con-
ducted by Lemmerman (13) et al. They used six different soils and
grew vetch, oats, barley, rye, wheat, clover, mustard, and buckwheat,
with the investigations extending over three years, 1907 to 1909, inclu-
sive. From the standpoint of yields the ratio had no effects within
wide limits. Stewart (33) reports soils having 16.88 per cent of calcium
oxid and 6.1 per cent of magnesium oxid which were cropped for 40
years without the addition of fertilizers, except in the case of sugar
beets, which received manure. The 8-year average yields are 80 bushels
for oats, 50.4 bushels for wheat, 262.3 bushels for potatoes, and 21.8
tons for sugar beets.

Wartiadi (38) used sand and water cultures with wheat and barley and
found that calcium and magnesium were beneficial or detrimental in
proportion to their relative amounts in the culture solution. Russell
(30, p. 144) finds no connection between the lime-magnesia ratio and
the productivity of the soil. Haselhoff (8) also failed to substantiate
Loew's theory, while Hopkins (9, pp. 170-171) found magnesium car-
bonate beneficial up to 0.8 per cent when added alone and in connection
with calcium sulphate in such amounts as to maintain a ratio of 4 to
7, respectively, of magnesium oxid and calcium oxid.

Gile (3) reports that with the chlorids of calcium and magnesium at
low concentrations the ratio exerted no influence, while at high con-
centrations it was effective. Good yields of pineapples (4) were pro-
duced from soils in Porto Rico when the ratio varied between i to 13
and 73 to i ; and in one field where the ratio of calcium oxid to magnesium
oxid was 1,461 to i a yield of 60 tons of sugar cane was realized.

July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 593

Pisciotta (28), an Italian investigator, reports the analysis of 60 soils
which show a wide variation in the lime-magnesia ratio, due to the
variation in the lime content. Patterson (25) found that magnesian
lime, which is claimed to be poisonous, gave the highest yields.

In summing up the literature studies previously mentioned, it will be
seen that Loew and his associates and Japanese students maintain the
theory of a definite lime-magnesia ratio, as do Ulbricht and Wartiadi,
whereas Dojarenko, Gossel, Konovalov, Meyer, Lemmerman, •Haselhoff,
Gile, and Patterson claim that a definite ration of lime to magnesia is
not tenable and, furthermore, lacks substantiation.

Lemmerman et al. have undoubtedly conducted the most extensive
investigations upon this subject and conclude that there is no correla-
tion between maximum crop productions and the ratio of lime to magne-
sia. Soils reported by Russell and by Gile show wide variations in the
lime-magnesia ratio, also in the percentages of these two elements, and
that there fails to be any correlation between the productivity of a soil
and its ratio of lime to magnesia.

Solution cultures show that a specific ratio of lime to magnesia is not
equally effective in dilute solutions and in concentrated solutions. This
indicates that the effectiveness is dependent upon the total balance of all
the salts in solution instead of merely the ratio of calcium to magnesium.

The preponderance of evidence appears to be against a definite ratio
of lime to magnesia, especially with respect to soil cultures in pots and
under field conditions. What really seems of first magnitude is the
resultant of all factors — that is, the climate, the plant, and structure,
reaction, micro-organic activity, and composition of the soil.

EXPERIMENTAL WORK

These experiments were planned with the idea of studying the effects
of calcium and magnesium upon plant growth when applied in different
natural and in artificially prepared forms. Studies were made to deter-
mine the amount of calcium and magnesium which the plants could
tolerate. The relation between the ratios of these two elements in the
plants, in the soils, and in the materials applied was also studied.

Dolomite, limestone, magnesite, calcareous soils, and brown silt loam
were used as sources of the natural forms, while prepared materials, such
as the carbonates, chlorids, and sulphates, served as sources of the arti-
ficial forms. Increasing amounts of the various forms were used, also a
variance in the ratio of calcium to magnesium was employed. The
earlier applications varied from o.i to 0.6 per cent of magnesium added
in magnesium carbonate and in magnesite. Later the following amounts
were employed: 2, 6, and 10 per cent of magnesium in magnesite; 10
and 12.7 per cent of magnesium in dolomite; o.i, o.oi, and o.ooi per
cent of magnesium in the carbonates, chlorids, and sulphates. In each
series sand or soil was used as a control.

594 Journal of Agricultural Research . vol. vi, NO. 16

DESCRIPTION OF PROCEDURE AND METHODS

Earthen pots 6.5 inches in diameter by 7.5 inches in depth were used.
Each pot contained 13.2 pounds of sand, while in the soil series each
contained 8.8 pounds of brown silt loam. Sand and soil were used as
mediums of control, and to these two materials were added the various
forms and amounts of calcium and magnesium.

Various< methods were pursued in extracting the sand. At first
dilute hydrochloric acid (HC1) was kept in contact with the sand for 48
hours, but this failed to remove all the calcium and magnesium. Later
the sand was extracted with stronger acid (1,350 c. c. of concentrated
hydrochloric acid plus i ,000 c. c. of distilled water) for periods of from 9
to 14 days. Sand was also digested on a steam bath for 4 days with this
same strength acid. None of the above processes were able to remove
all the calcium and magnesium from the sand, as will be seen from the
analysis reported.

At intervals varying from 10 days to 2 weeks plant food was added
from the following solutions :

(i) Potassium sulphate, 50 gm. to 2% liters of water; (2) ammonium
nitrate, 80 gm. to 2>£ liters of water; (3) disodium phosphate, 26.1 gm.
to 2^2 liters of water; (4) ferric chlorid, 0.4 gm. to i liter of water.

The calcium and magnesium were applied in forms previously men-
tioned. The moisture content of the sand was at first 12 per cent, but
it was later raised to 14 per cent, while for the brown silt loam it was 24
per cent. Every 10 days the pots were brought to standard weight by
adding distilled water.

All crops were grown in the agronomy greenhouses at the University
of Illinois. The principal crops used in these studies were wheat (Triti-
cum spp.), alfalfa (Medicago saliva), soybeans (Sofa max), and cowpeas
(Vigna sinensis). Oats (Avena saliva}, clover (Trifolium pratense), timo-
thy (Phleum pralense), and sweet clover (Melilolus alba) were also used
to test the effect of artificial carbonates upon germination.

In the wheat and soybean series, 10 seeds per pot were planted and
7 plants permitted to grow, while for alfalfa 15 plants were permitted
to grow whenever possible.

In making determinations for calcium and magnesium, the soils
were first fused with sodium peroxid and from this point the usual
method was employed. The calcium oxalate was dissolved in dilute
sulphuric acid (H2SO4) and the calcium calculated from the amount of
N/io potassium permanganate required to oxidize the oxalic acid thus
formed. The magnesium was precipitated as magnesium-ammonium
phosphate and burned to the pyrophosphate. In analyzing the plants 2
gm. of finely ground material were ashed, taken up in hydrochloric acid,
and the calcium and magnesium determined as above stated. Acid
extractions of the dolomites and limestones proved as good as fusions.

July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 595

TABLE I. — Composition of materials supplying calcium, and magnesium to the soil

Material.

Calcium
carbonate.

Magnesium,
carbonate.

Calcium.

Magnesium.

Molecular
ratio of
calcium to
magnesium.

Dolomite Ci

Per cent.
47. 6q

Per cent.
T.C. 26

Per cent.

Per cent.

T4- 8

Dolomite €3

qi. 18

44- 0

5X. 2

Magnesite C4

08. T,7

Limestone l
Brown silt loam

84.2

5-85

o. 7.O5

°- 35

c:o. 6

Calcareous soil

"?. <?8

2. 64

e:7. 8

Sand extracted with dilute
hydrochloric acid for 48
hours

. 0142

. 016

Sand extracted with con-
centrated hydrochloric
acid for four days on
a steam bath

. 0128

. 0080

Sand not extracted

. 017

. 0148

i From Columbia, 111.

The brown silt loam used in series C and D was taken from the surface
of sod land and had only the coarser roots removed. The calcareous
soil was taken from a layer varying from 8 to 12 inches in thickness and
72 inches below the surface in the forestry near plot 719 of the north
farm of the university. The coarser pebbles were removed before using.
The analysis in Table I refers to the portion used in growing crops; the
coarser pebbles show a higher content of calcium and magnesium, or'
13.34 Per cent of calcium and 5.97 per cent of magnesium.

The 6,000 gm. of sand, after being extracted with hydrocnloric acid,
contained for each pot from 768 to 852 mgm. of calcium and from 540
to 960 mgm. of magnesium. From the following tables it will be seen
that the plants had the power to obtain considerable quantities of the
apparently insoluble calcium and magnesium silicate, as they obtained
quantities in excess of the amount added in the seeds, although they
show lower contents than plants grown in an excess of these materials.
The chemically pure magnesium carbonate gave an immediate alkaline
reaction to phenolphthalein upon the addition of distilled water. Dolo-
mites Ci and €3 likewise showed an alkaline reaction to this indicator,
but only after having been in distilled water over night. Magnesite
after standing in distilled water from 8 to 12 hours was alkaline to
phenolphthalein, as was also the calcareous soil.

In experimenting with artificially prepared magnesium carbonate, a
great deal of care was taken to obtain the alkali-free substance to begin
with. This can be prepared by a precipitation from solution with ammo-
nium carbonate. Magnesium carbonate in the presence of water has a
great tendency to hydrolyze, which may at least partially explain its
poisonous effect.

596

Journal of Agricultural Research

Vol. VI. No. 16

EFFECT OF MAGNESIUM AND CALCIUM IN PREPARED CARBONATES AND
IN DOLOMITE UPON WHEAT AND ALFALFA GROWN IN SAND (SERIES A
AND B)

The sand used in series A and B was extracted as previously described,
washed free from acid, and the application made on the moisture-free
basis. Pots i and 2 of series A and pots 21 and 22 of series B received
no calcium or magnesium. Pots 3 and 4 of series A and pots 23 and 24
of series B received 2 per cent of dolomite Ci or 0.2 per cent of the element
magnesium. Pots 9 to 20, inclusive, of series A and pots 29 to 40, inclusive,
of series B received magnesium and calcium in prepared carbonate in
amounts varying from o.i per cent to 0.6 per cent of magnesium. The
magnesium carbonate was alkaline and of the following formula:
Mg(OH)2.4MgC03.

Table II contains the yields for the above treatments. When added
to sand, the lowest applications of magnesium in the prepared carbonate
very materially retarded germination and inhibited growth; whereas
amounts of 0.6 per cent of magnesium in dolomite caused no injury and
even benefited growth.

The ratio of calcium to magnesium throughout this and all succeeding
tables is reported as molecular calcium to molecular magnesium, with
calcium always expressed as 5. The yields and percentages in all the
tables are reported on the water-free basis. The wheat, series A, was
harvested 83 days after being planted, while the alfalfa, series B, was
'harvested 84 days after being planted.

TABLE II. — Yields of wheat and alfalfa (in grams per pot on a water-free basis) in sand —
series A and B

Treatment.

Molecular
ratio of
calcium
to mag-
nesium.

Wheat, series A.

Alfalfa, series B.

Pot No.

Tops.

Roots.

Pot No.

Tops.

Roots.

None

I

2

3
4

!

I

20. 9
18.5

7.07
23.0
23.0
17.8
20.7
10.8

22.2

23.2

18.8
15.0
10. o
12.9
6.3

21
22

23

24

11
11

5-16
3.12

6.24
7-84
5-97
5.61

7-75
7.21

6.42
2.58

8-73
12.47
9. o

8.02

10.34

9.0

None

Percentage of magnesium in dolo-
mite Ci:

O. 2

5:4.8

5:4.8
5^8
5:4.8
5:4.8
5:4.8

2

:t::

.6

The pots receiving magnesium and calcium in the prepared carbonates
in a ratio of calcium to magnesium, as 5 to 4, inhibited germination and
permitted no growth.

July 17. 1916 Influence of Calcium and Magnesium on Plant Growth 597

Table III shows the analysis of the plants reported in Table II. The
results here reported are the average of four determinations from dupli-
cate pots.

From Table III it can be seen that the alfalfa is a heavier feeder on
calcium and magnesium than is wheat, and that the percentages and the
total amounts removed by the plants tend to increase with the increase
in application, except where the calcium and magnesium are applied in
the artificially prepared carbonates, in which case the lowest application
is sufficient to inhibit growth and retard germination.

Throughout all the series the general tendency was for the calcium
and magnesium content of the plants to increase with the increase in
application. Wheeler (39) found that when magnesium was applied in
the form of the sulphate the crop showed the ratio of magnesium oxid to
calcium oxid to be as i to 1.13, but when magnesium was not present in
the fertilizer the ratio of magnesium oxid to calcium oxid was i to 2.7.

TABLE III. — Analyses of wheat and alfalfa — series A and B

WHEAT STRAW

Pot No.

Substance added.

Composition of plants.

Calcium.

Magne-
sium.

Calcium.

Magnesium.

Molecular
ratio of
calcium to

sium.

i and 2 «
3

Per cent.
o. 0142
•333
•999

Percent.

o. 0165

.2
.6

Mgm.
37-0
68.5
60. i

Per cent.

o. 187

. 298
• 386

Mgm.
21.4
62.6

66.6

Percent.
0. 1 08
.271
.421

S-'S-I
5:7.6
5:9.I

7 and 8

WHEAT ROOTS

i and 2

. 0142

.0165

43-4

.187

24-8

.09

5:4.1

3

•333

. 2

85-3

• 452

55-3

.292

5:5-4

7 and 8

•999

.6

91-8

.96

47-9

•50

5:4-35

21 and 22 a

6 84

164

23 and 24

181 o

27 and 28

6

4.8 6

ALFALFA ROOTS

8 *2

6 26

<r6 i

23 and 24
27 and 28

•333

48.8

.46

e6i

50. o

78 Q

.472

81?

5:8.5

0 Pots i, 2, 21, and 22 were extracted sand and received no calcium and magnesium.

598

Journal of Agricultural Research

Vol. VI, No. 16

EFFECTS OF CALCIUM AND MAGNESIUM IN PREPARED CARBONATES AND
IN DOLOMITE UPON WHEAT AND ALFALFA IN BROWN SILT LOAM (SERIES
C AND D)

Magnesium and calcium in prepared carbonates were less harmful in
brown silt loam than in sand (series C and D). In fact, applications of
o.i per cent of magnesium or 0.35 per cent of magnesium carbonate
gave an increase over the check, and 0.7 per cent of the carbonate was
practically as good. It must be remembered that the soil before treat-
ment contained 0.305 per cent of calcium and 0.352 per cent of magnesium.
The calcium and magnesium were added in the relation 'of 5 to 4, but the
amounts in the soil changed this ratio to 5 to 7.1. Applications of 3.5
tons of prepared magnesium carbonate per acre were beneficial, 7 tons
were about equal to the check, while upward of 10 tons caused practically
no growth of the plants.

TABLE IV. — Yields of -wheat and alfalfa (in grams per pot on a water-free basis') in brown
silt loam — series C and D

Treatment.

Molecular
ratio of
calcium
to mag-
nesium.

Wheat, series C.

Alfalfa, series D.

Pot

No.

Tops.

Roots.

Pot

No.

Tops.

Roots.

5:9.6
5:9.6

/ 5:7-
I 5:7-
/ 5 = 7-
I S:?-
/ S:?-
j 5:7-
f 5:7-
I S:?-
/ S:?.
I 5:7-
/ S:?-
I 5:7-

/ 5:4.8
I 5:4-8
I 5:4.8
IS 4-8
/ 5:4-8
j 5:4-8
/ 5:4-8
\ 5:4.8
/ 5:4-8
I 5:4-8

41
42

43
44
45
46

47
48

49
50
5i

52
53

54

P
%
8

61
62
63
64

8.9
9-3

n. 6

II. O

8.1
8.1

i-45
4.08

&

1.85
.09
.09

.09

9-52
10.5
9. 61
9.07
10. o
9-52
8.9

5-7i
6. 07
7-52

6.8

7-9

7.16
7.0

5-55
6. 07
1.81
3-17
•72
.18

2-35
.09
.09

5-45
6. 07
8.15

IV

8.15

4-53
4.62

4-53
4-53

65
66

67
68
69

70

7i
72

73
74

8
g

g

81
82
83
84
85
86

87
88

4.64
4. 28

5-96
5-35
2.58

3-°3
.09
2.58

6.86
6-53

6-95
6-5
2.49

2.85

"1.69

Do

Percentage of magnesium in mag-
nesium carbonate plus calcium car-
bonate :

.6

Percentage of magnesium in dolomite
Ci:

O.2

•4
6

5-i7
S-o
5-35
5.08

4-37
5-43
5-43
5.60

5-J7

5-52

6. 05
5.08
6.85
5-88
3-74
6.15
4.72
4- 64
5.08
3-65

Maclntire (18), while working with three different kinds of soils, found
that 8 tons per acre of precipitated magnesium carbonate were decidedly
toxic to wheat. He also found that both the oxids and the carbonates of
precipitated magnesium were many times more soluble than the cor-
responding forms of calcium, while in the case of the native mineral

July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 599

carbonates limestone was i .62 times as soluble as dolomite and more than
3 times as soluble as magnesite.

Applications of dolomite Ci up to 40 per cent caused no injury to
either wheat or alfalfa.

Table IV shows the treatments and yields of series C and D. Analyses
of these plants are reported in Table V. Series C (wheat) was harvested
83 days after planting and series D (alfalfa) was harvested 84 days after
planting.

From Table V it can be seen that wheat grown in soil (pots 41 and 42)
shows 0.279 per cent of calcium and 0.256 per cent of magnesium, but
when grown in extracted sand (Table III, pots i and 2) it had only 0.187
per cent of calcium and 0.108 per cent of magnesium, showing that there
is a decided tolerance for these two elements. By comparing the wheat
with the alfalfa it can be seen that, while alfalfa is a heavier feeder than
wheat on calcium and magnesium, the proportional amounts of calcium
are greater in alfalfa than in wheat.

TABLE V. — Analysis of wheat and alfalfa grown in brown silt loam — series C and D

WHEAT STRAW

Pot No.

Substance added.

Composition of plants.

Calcium.

Mag-
nesium.

Calcium.

Magnesium.

Molecular
ratio of
calcium
to mag-
nesium.

41 and 42

Per cent.
0.305
•527
.971

6^30

Per cent.
0.352
.458
.67I
.2

4. o

Mgm.

Ill
9.76

35-4
29.2

Per cent.
0.297
•297
•352

•353
•43

Mgm.
23-3I
52-7
32-8
33-8
3I.O

Per cent.

o. 256

•467

•337
• 456

5: 7-2
S:J3- i
5:28. i

5: 7-9

5 8. 8

43 and 44

47 and 48
55 and 56
63 and 64

WHEAT ROOTS

41 and 42

•3°5

•352

21. 9

. 298

19. 6

.266

5= 7-5

43 and 44

•S2?

-458

29.8

.419

•25.1

-352

5: 7

47 and 48

.971

.67I

9-7

•352

15-5

.626

5:14-1

55 and 56
63 and 64

•3X5
6-3

. 2

4- o

34-0

50. o

•53

I. IO2

22.8

34-1

•397
•752

5=6
5: 5-7

ALFALFA HAY

65 and 66
67 and 68

•305
•527

•352
.458

71. o
78.4

1-595
1.56

17.7
35-3

•398
.624

S: 2.2

5: 3-8

71 and 72

.971

.671

11.4

.86

12. 82

.96

5: 9-3

79 and 80

•3i5

. 2

85-5

1.684

2S.0

.492

5: 2.4

87 and 88

6-30

4- o

98.5

1.84

27.8

.521

5: 2.3

ALFALFA ROOTS

65 and 66
67 and 68

•305

•527

•352
-458

21.46
21. 2

.326
.314

34-0
37-5

. 462

.558

5:11.8

71 and 72

.971

.671

10. 64

.628

17. 2

I. 00

5:I3- 3

79 and 80

. 2

25. o

•449

30. o

•54

5:i°

87 and 88

6.30

4-0

96.0

2.2

59-2

5: 5- J

6oo

Journal of Agricultural Research

Vol. VI, No. 16

EFFECT OF MAGNESIUM AND CALCIUM IN DOLOMITE, MAGNESITE, AND
PREPARED CARBONATES UPON WHEAT AND ALFALFA IN SAND (SERIES
E AND F)

Table VI shows the yields of wheat and alfalfa when grown in sand
and treated with increasing amounts of magnesium in magnesite. The
applications vary between o.i per cent of magnesium and 0.6 per cent
of magnesium or 0.35 to 2.1 per cent of megnesite. Chemically pure
calcium carbonate was added to make a ratio of calcium to magnesium
equal to 5 to 4. The wheat and alfalfa in these two series were grown
to maturity, the seeds being ground up with the straw and an analysis
of the composite made.

There was but little seed upon the alfalfa, owing to the fact that it
was grown under screens and the fertilization was poor. However, the
treatments seemed to cause no injury except where magnesium was
applied in the form of the prepared carbonates in pots 104 and 120.

TABLE VI. — Yields of wheat and alfalfa (in grams per pot on a water-free basis) in mag-
nesite—series E and F

Treatment.

Molecular
ratio of
calcium
to mag-
nesium.

Wheat, series E.

Alfalfa, series F.

Pot
No.

Tops.

Pot
No.

First
crop,
tops.

Second
crop,
tops.

Roots.

None

89

90

91
92

93
94

9I
96

97
98

99

100
101

IO2
I03

104

7-25

6-53
7.16
5-98
9.88
10. 96
6.8
7.07
7.8

9-15

7.8
11.4
6.25

9.42
10.86

105

105
107
108
109
no
in

112

JI3

114

JI5
116
117

118
119

120

6.86

6. oo

8-35
6.77
6.25
5-72
5-9
5-64
6.77
6. 07
7.92
7.48
7-32

6-34

5-72

5-2

5-36

5-8
6.16
4-94
5-2

ti

5.02
4-31
4-4
5-2

5-55

5-9
4.66

3.78

7-13
5-46
7.48
4-57
3-96
4.32
4.48
I.8S
1.49
2-38
5.02

3-52

4-93
2.64

Percentage of magnesium in
magnesite plus calcium car-
bonate:

O.I

/ 5:4
I 5:4
/ 5:4
I 5:4
| 5H
S;4
/ 5:4
j 5:4
/ 5:4

5-4

/ 5:4
I 5:4

/ 5:5-2
I 5:5-2

5:4

.2

.3

• 4 ... .... ...

.e

.6

Percentage of magnesium in
dolomite €3:
o 6

Percentage of magnesium in
magnesium carbonate

Table VII shows that the higher treatments have higher contents of
calcium and magnesium in the plants. The wheat grown in sand (pot
89) shows only 3.3 pounds of calcium and 2.6 pounds of magnesium
per ton, as against the pots treated with larger quantities of magnesite

Influence of Calcium and Magnesium on Plant Growth 60 1

(100 and 101), which show 5.52 pounds of calcium and 10.88 pounds
of magnesium.

Gile and Ageton (5, p. 44) show that many plants such as soybeans,
sugar cane, and sunflower have higher lime contents when grown upon
calcareous soils and that the increase in lime content tends to decrease
the amount of magnesia, iron, and potash.

TABLE VII. — Analysis of wheat and alfalfa grown in magnetite — series E and F

WHEAT STRAW

Pot No.

Substance added.

Composition of plants.

Molecular
ratio of
calcium to
magne-
sium.

Calcium.

Magne-

Calcium.

Magnesium.

go

Per cent.

o. 014

. 222
1-332
.967

Per cent.
0. 01 6
. IOO

.60

.60

Mgm.
12. 0

i°-S5

24. 4

24. 1

Per cent.
o. 165
•154
.276

•237

Mgm.
9-36
16-55
48.1

32-3

Per cent.
o. 130

.241
•544
•317

5: 6.5

S«3

5:16.4
5:11.1

oo and or

ALFALFA HAY

105

. 014

. 016

87.4

i. 275

41. o

.598

5:9. 3

106 and 107
116 and 117

. 222
I- 332

. IOO

. 60

106.8

98.5

1-49
i. 345

45- i
56. o

•63
. 69

5:3-8

5:4. 2

118 and 119

.967

.60

93-2

^•55

39-2

•653

5:3'5

ALFALFA ROOTS

105 .

. 014

. 016

2<;. 4

672

14. Z2

. 38?

5:4. 8

106 and 107
116 and 117
118 and 119

. 222
1.332
.967

. 10

.60
.60

55-7
63.0
65.2

.89
1.48

!•' 73

43-8
61. i
35-8

Jc

. 64

I- 434
•95

5:6

5:8
5:4.6

EFFECT OF MAGNESIUM AND CALCIUM IN CALCAREOUS SOIL, MAGNESITE,

DOLOMITE, AND PREPARED CARBONATES UPON WHEAT AND ALFALFA
(SERIES G AND H)

It can be seen from Table VIII that the ratios of calcium to magne-
sium vary from one of 5 to 3.8 to one of 5 to 125 and that in both cases
considerable growth occurred. However, in pots 135, 136, 161, and 162,
receiving 35 per cent of magnesite and 100 gm. of calcium carbonate,
the plants showed a yellow color and some sickness; still, in the case
of alfalfa the plants were able to set some seed. The yields in pots 123,
124, 149, and 150, which received calcareous soil only, were somewhat
less than where sand was mixed with the soil, owing to the soil being
decidedly plastic and possessing a less desirable physical condition.

602

Journal of Agricultural Research

Vol. VI, No. 16

Plate LXXXIV shows the difference between some of the treatments
in series G. Observe the small growth of the wheat in the pot receiving
6 per cent of magnesium in magnesite. This is due to the physical con-
dition caused by applying the magnesite in a finely ground form, which
caused a setting that resembled cement, whereas in the pot with 10 per
cent of magnesium almost twice as much magnesite was applied, but
in a coarser form. For the ratios in these pots see Table VIII.

Plate LXXXIV shows alfalfa growing under similar treatments.

. — Yields of wheat and alfalfa (in grams per pot on water-fr
dolomite, and magnesite — series G and H

basis) in soil,

Treatment.

Molecular
ratio of
calcium
to mag-

Wheat, series G.

Alfalfa, series H.

Pot
No.

Tops.

Roots.

First
crop.

Second
crop.

Third
crop.

Pot
No.

None

Percentage of magne-
sium in calcareous
soil:

2 64

,

121
122

123
124
125
126
127
128
I29
13°

132
133
134

137
138

i!o8
21.93

21. O

26. 9

27-3
24-5
28.62

35-5
35-8

30.8
18.2
17.4

2.17
3.26

6-53

2. 28

9-59

5-63

l&

149

152
153
154
155
156

158

159
160
161
162

163
164

{ 5''3'l
/ S-I.S
i 5;3.8

I 5:3^8
I 5:3.9

; 5:4

)5=4

/ 5:75
i 5:75.

| 5;I25

/ 5:5.2
1 5:5.2

7-15
14.7
16. 2

10.4
19.4
9.25

14.4
10.32

II. 05

io. 05
4. 26
i. 18
6.25
6.16

7.22
7.04
9.41
9-59

10. II
10. O2

10.28
9.68

9-15

io. 9
5-28
5-9
4-48

10. II

5-2

7-47
7.22
ii. 7
12.35
13-72
12.3
9.68
10.46

8.97
9.86

8-45
io. 62

5-02

9-77
9-77

12.6
IO. O2

13.0

10.9

12.3

9-59
io. 71

7-83

8.8
8.88

3-69
2.28

9-59
9-77

I 728

o. 672

o. 344
Percentage of magne-
sium in magnesite
plus calcium car-
bonate:

2.O

6.0

10.0

Percentage of magne-
sium in dolomite
Ci:

12-7

One of the most noticeable facts brought out in these series is the great
sensitiveness of the plants to small quantities of calcium and magnesium,
also their ability to utilize relatively insoluble forms of these two ma-
terials. In pots 121 and 122, Table IX, and pots 147 and 148, Table X,
the plants were grown in extracted sand receiving no calcium and mag-
nesium and were able to obtain considerable quantities that had not been
removed by the acid extractions. The alfalfa was even able to mature
a few seeds.

July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 603

TABLE IX. — Analysis of wheat grown in soil, dolomite, and magnesite — series G

WHEAT STRAW

Substance added.

Composition of plants.

Pot No.

Molecular

Calcium.

Calcium.

Magnesium.

calcium

to mag-
nesium.

Mt,m

Per cent.

Mom.

Per cent.

121 ....

o. 014

o. 016

24. 6?

o. 165

123 and 124
125 and 126

5-78
2.897

2.64
1.328

76.1
130.0

•358
.48

52-9

78.7

.249
.29

5: 5-7
5: 5

129 and 130

•732

• 344

156. i

.485

•3°5

5: 5-2

131 and 132

4-44

2. O

88.6

.248

188. o

•527

5:I7- 7

135 and 136

.666

IO. O

66.8

•375

170. o

•955

5:21.2

137 and 138

20.47

I2.7

15.6

•574

19.9

•73

5:12.7

WHEAT ROOTS

121

. 014

. 016

18. 7

.287

8. 14

5:3 6'

123 and 124

<;. 78

2.64

85. 7

• 795

35.6

33

125 and 126

2. 897

i. 328

76. 5

• 584

44. -i

. 332

T4 8

129 and 130

•732

•344

63-5

3°-7

.248

5:4

131 and 132

4-44

2. 0

129.4

1.224

163.9

1.6

5 : 10. 8

135 and 136

.666

10. 0

22.25

•358

44-75

•72

5:16.8

The high percentage of magnesium in the plants grown in pots receiv-
ing 35 per cent of magnesite is also characteristic of tolerance. Like-
wise a high magnesium content tends to accompany plant sickness. In
the case of wheat grown in dolomite, pots 137 and 138, there was a
higher percentage of calcium than in any other treatment. A ton of
water-free material contained 11.48 pounds of calcium and 14.6 pounds
of magnesium, but a ton of dry matter from the treatment with 25 per
cent of magnesite showed 7.5 pounds of calcium and 19.1 pounds of
magnesium per ton, as against the check in sand which contained 3.3
pounds of calcium and 2.64 pounds of magnesium. Alfalfa tends to show
the same thing, except that it is a decidedly heavier feeder upon these
two elements than is the wheat crop.

The wheat, Table VIII, was planted on January 26, 1914, and harvested
on May 27, 1914, making 121 days of growth. The alfalfa was also planted
on the above date and the first crop harvested on May 27, 1914. The sec-
ond crop was harvested 127 days later, on October i, 1914, and the third
crop on November 12, 1914, after 42 days of additional growth.

By comparing pot 147, Table X, for the three crops, it will be seen
that the second crop of alfalfa contained practically three times as much
calcium and magnesium per ton as did the first crop, while the time of
growth was about the same. The third crop contained about twice as
much calcium and magnesium per ton as did the first crop, and its period

604

Journal of Agricultural Research

Vol. VI. No. i«

of growth was only 42 days. This is due chiefly to the extensive de-
velopment of roots, making it possible to utilize more of the small quan-
tities of calcium and magnesium remaining in the extracted sand, for in
the other pots where these two elements were added such striking differ-
ences do not occur in the different crops.

To each pot receiving 15 alfalfa seeds, 0.19 mgm. of calcium and 0.32
mgm. of magnesium were added in the seed, and for the three crops
164.5 nigm. of calcium and 90.72 mgm. of magnesium were removed.
This indicates to what extent the- plants may attack relatively insoluble
compounds.

X. — A nalysis of alfalfa grown in soil, dolomite, and magnesite — series H
ALFALFA, FIRST CROP

Pot No.

Substance added.

Composition of plants.

Calcium.

Magnesi-
um.

Calcium.

Magnesium.

Molecular
ratio of
calcium
to mag-
nesium.

147 and 148 . . .

o. 014
5-78
2-897
•732
4.44
.666
.666
20.47

o. 01 6
2.64
1.328
•344

2. O

6.0

IO. O

12.7

Mgm.
II. 2
98.41
136.0
127.8

92.S
23-8
76.7
34-2

Per cent.
0.382
1.382
1-432
1.28
.922
.426
1.05
.66

Mgm.
5-72
26. 52
33-92
34-5
74-5
52-3
83-7
33-8

Per cent.

o. 198
•373
•357
.346
• 744
•936
i. 148
•633

5: 4-3
5: 2.2
5: 2

5: 2.2

5: 6.8

5:18.3

5: 9- I
5: 8

149 and 150 .

151 and 152 .

jce and ic6 .

157 and 158

161 and 162

163

ALFALFA, SECOND CROP

147

.014

. 016

i°5- 3

.096

63.8

.665

S.'S

149 and 1 50

5.78

2.64

JI7- 5

• 6lS

31. 8

• 434

z:2 2

151 and 152

2.897

1.328

172. o

.402

50. o

.407

5:2-5

155 and 156

•732

• 344

114-5

.138

50. o

•5*7

5:3-7

157 and 158

4-44

2. 0

103.4

.098

67.6

.718

5:5-4

159 and 160
161 and 162

.666
.666

6.0

10. O

75-o

102. O

.785
.381

76-5
73-6

• 803

I. OO

5:8-5
5:6

168

20.47

12.7

104.4

.068

69.4

.711

5:5-5

ALFALFA, THIRD CROP

147

.014

. 016

48.0

• 854

21. 22

•378

5:3-6

149 and 150

5-78

2. 64

no. o

•974

31-6

.291

5:2.4

151 and 152

2.897

1.328

no. 2

.922

32.2

.27

5:1-9

155 and 152

•732

•344

78.75

•955

29. 62

•32

5:2.8

157 and 158

4.44

2. O

85-0

.962

40.7

.461

5:4

159 and 160.. .. ,

.666

6.0

40.8

.922

39-8

•783

5:7

161 and 162

. 666

IO. O

Si. 6

• 87

CA. 7

. 922

?:o. 2

163

20.47

12.7

0*. «

96-5

•99

OT~ /

49.0

•5°3

O 7'

5H.2

July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 605

EFFECT OF MAGNESITE AND DOLOMITE UPON WHEAT AND SOYBEANS

(SERIES i AND j)

Series I had wheat grown in the pots and then turned under, and wheat
was then replanted in the same pots; while series J had cowpeas grown
and turned under and then soybeans planted, except in pots 182 and 183,
from which the cowpeas were removed before the soybeans were planted.
The cowpea hay grown in pots 182 and 183 contained 0.4 per cent of
calcium and 0.179 Per c^t of magnesium, in a ratio of 5 to 5.7, and
removed from each pot 32 mgm. of calcium and 14.32 mgm. of magnesi-
um. In 10 seeds planted there was 0.58 mgm. of calcium and 1.59 mgm.
of magnesium. The above pots contained extracted sand.

Figure i of Plate LXXXV shows the effect of succeeding crops when
grown upon extracted sand. The pot at the left marked "sand only"
has had no other crop preceding it, while in the middle pot cowpeas
were grown and removed, taking out some of the most readily available
calcium and magnesium. From the pot at the right three crops of alfalfa
were removed, taking out 164.5 mgm. of calcium and 90.72 mgm. of
magnesium.

Dolomite has no detrimental effect upon the crops used throughout
these experiments. However, the addition of larger quantities of mag-
nesite — for example, 35 per cent — caused considerable yellowing of the
leaves, and the plants were able- to mature but few seeds. Plate
LXXXV, figure 2, shows that the plants growing in dolomite have quite
a number of bean pods, while in the magnesite pot none are visible and
the uppermost leaves are sickly. This yellowing of the uppermost leaves
while the lower ones remain green differs from true translocation and
accompanies high magnesium applications. The yellow leaves have a
higher magnesium content than do the healthy ones, as sickly -leaves
from the plants taken from pot 185 show 0.955 Per cent of calcium and
1. 1 1 per cent of magnesium, while the healthy leaves from the same
plants showed 0.896 per cent of calcium and 0.88 per cent of magnesium,
respectively.

Schulze and Godet (31) found more calcium in the husk and more
magnesium in the seed of lupine, pine, pumpkin, castor bean, sunflower,
and various nuts. •

Plate LXXXVI, figure i, shows the comparative growths of soybeans
in brown silt loam and dolomite. Evidently the brown silt loam would
have been improved by applications of some limestone or dolomite.

The differences of yields of duplicates in Table XI are due chiefly to the
differences in the duration of growth. In the wheat, series I, pots 173,
J75> J77» and 179 were harvested 65 days after planting, while their
duplicates were harvested 12 days earlier. In the soybean, series J, pots
181, 184, 186, and 188 were harvested 53 days after planting, while their
duplicates were permitted to mature, standing until 80 days after
planting.

6o6

Journal of Agricultural Research

Vol. VI. No. 16

TABLE XI. — Yields of wheat and soybeans (in grams per pot on the water-free basis) in
dolomite, magnesite, and sand — series I and J

Treatment.

Molecular
ratio of
calcium
to mag-
nesium.

Wheat, series I.

Soybeans, series J.

Pot No.

Tops.

Roots.

Pot No.

Tops.

Roots.

None

f
I

(SH

1 S:4
/ 5^25

I 5^25

/ 5:5.2
I 5:5-2

173
174

J75
176
177
178

179
1 80

0.9
• 3

4.8
1.6
5-3
i. 8

5-3
1.9

0.4

•4

2-9
I. I

i-7

I. 0

3-2
•9

181
182

I83
184
185
186

187
188

I. O
I. 2

5-6
4-7
4-0
3-2

6-3
3-4

0-5

Percentage of magnesium in mag-
nesite plus calcium carbonate :

•9

Percentage of magnesium in dolo-
mite C3 :

12

.8

•7

Table XII shows the analyses of wheat grown in series I.

TABLE XII. — Analysis of straw of wheat grown in dolomite, magnesite, and sand —

series I

Substance added.

Composition of plants.

Pot No.

Molecular
ratio of

Calcium.

^e- , Calcium.

Magnesium.

calcium

to mag-

nesium.

Per cent.

Per cent.

Mgm.

Per cent.

Mgm.

Per cent.

174

o. 014

0. Ol6

1.32

0.44

0.38

o. 127

5: 2. 4

173

. 014

. 016

I. 21

• I35

I. 26

• X4

5: 7- r

176

/j. 44

2. O

10.88

.68

13. 04

.815

5 : 9-9

17?. ..

i\, 44

2. O

21. 36

, 445

36. 78

• 783

5: 14. 6

178 ..

. 666

IO. O

8.87

• 403

18. 03

i. 002

5: 16. 9

177

.666

IO. O

16. 16

• ^o?

40. 54

.765

5 '.21

180

20. 47

12. 7

10. 26

• ^4

ii. 38

• 599

z: 9. 2

179

20.47

12.7

24.11

•455

22.15

.418

5: 7-6

Comparisons of the contents of plants at different stages of growth are
reported in Table XIX.

THE EFFECT OF MAXIMUM QUANTITY OF CALCIUM AND MAGNESIUM UPON
WHEAT AND SOYBEANS IN SAND (SERIES K)

Analysis of sand treated by different methods shows the hot-extracted
sand to contain only slightly less calcium but considerably less magne-
sium than the cold-extracted sand.

Table XIX shows the analysis of wheat and soybeans grown in such
sands. It can be seen that the soybeans contained only slightly more of
these two elements than was in the seed, but it must be remembered that
scarcely any growth occurred. However, the wheat, pots 193 to 196,
contained from 12 to 22 times as much calcium and 4 times as much

July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 607

magnesium as was added in the seed. Now, in pots 199 to 202, where
a small amount of easily available calcium had been applied, the per-
centage in the plants was materially increased.

Attempts were made to grow wheat and cowpeas in paraffin, so that
they would have no access to calcium and magnesium. However, this
permitted but little growth, and analyses of the total plants thus grown
showed their calcium and magnesium contents to be equivalent to the
amount present in the seed.

TABLE XIII. — Analysis of wheat and soybeans grown in extracted sand — series K

SOYBEAN PLANT

Substance

Composition of plants.

added in

seed.

Pot No.

Treatment of sand.

;

Molecular

Calcium.

Magnesium.

ratio of
calcium
to magne-

Cal-
cium.

Magne-
sium.

sium.

Mom

Per ct.

Mgm.

Per ct.

Mgm.

Mgm.

1 89 and 190°

Extracted with hy-
drochloric acid

2.15

0.293

2.77

0.376

5 : 10. 6

I. 16

2.32

in the cold.

191 and 192

Extracted with hy-
drochloric acid

1-5

•335

1.65

•369

5- 9-2

I. 16

2.32

on steam bath.

WHEAT PLANT

193 and 194

Extracted with hy-
drochloric acid

.67

. 22

.78

• 256

S: 9-7

.03

.18

' in the cold.

195 and 196

Extracted with hy-

•36

.168

.72

•337

5:16.7

• °3

.18

drochloric acid

on steam bath.

197 and 198

0.2 gm. sodium bi- j .80

• X55

•74

.144

5: 8

•°3

.18

carbonate (Na

HC03).

199 and 200

0.3 gm. sodium bi-

i. 14

•3

•35

•093

5: -2-5

• °3

.18

carbonate (Na-

HC'O3) 0.05 gm.

calcium nitrate

(Ca(NOs),).

201 and 202

0.2 gm. sodium bi-

•34

.247

.48

•35

5:11.8

• °3

.18

carbonate (Na-

HCO3) 0.05 gm.

calcium nitrate

(Ca(N03)2) 0.0317

gm. magnesium
sulphate (MgSO4)

a The containers in this series were tall Jena beakers holding 1,350 gm. of sand.

From Table XIII it can be seen that the plants contained more calcium
and magnesium than was added in the seed, thus showing their power
to obtain these two elements from sand that had been previously extracted
with acid.

6o8

Journal of Agricultural Research

Vol. VI, No. 16

EFFECT OF MAGNESIUM AND CALCIUM IN SULPHATES, CHLORIDS, AND
CARBONATES UPON WHEAT AND SOYBEANS IN SAND (SERIES L AND M)

When calcium and magnesium were applied in sulphates, chlorids,
and carbonates the smaller applications gave the highest yields. As
recorded in Table XIV, o.i per cent of magnesium in the carbonate
inhibited germination and permitted no growth, whereas this quantity
in the sulphates and chlorids gave considerable growth; however, the
chlorids were more detrimental than the sulphates, while at lower concen-
trations, such as o.oi and o.ooi per cent of magnesium, the carbonates
gave the best growth, the chlorids being the most detrimental. In the
case of soybeans all the chlorid treatments permitted practically no seed
formation, while treatment with smaller quantities of carbonates gave
considerable seed. The root formation was relatively the same as the
top growth, the detrimental effect accompanied short thick roots which
appeared brownish or reddish brown. Plate LXXXVII shows this
comparative root growth. Plate LXXXVIII, figure i, shows the
comparisons of wheat when grown in extracted sand and in dolomite.
Figure 2 shows the retarded growth of wheat due to the chlorids of
magnesium.

TABLE XIV. — Yields of -wheat and soybeans (in grams per pot on the water-free basis) in
the sulphates, chlorids, and carbonates of magnesium and calcium — series L and M

Treatment.

Molecu-
lar ratio
of cal-
cium
to
magne-

Wheat, series L.

Soybeans, series M.

Pot No.

Tops.

Roots.

Pot No

Tops.

Roots.

219

220

203
204
205
206
207
208

209
2IO

S-8

2. I
2.4

331

4-4

5-i
3-8

1.6

i-5

3-°

I. O

•4
. i

•5
•3

:l

• 7
.6

237
238

221
222
223
224
225
226

227
228

i-3

2. O

a

5-5
4.9
3-6
4.0

2.4

2. I
2.6

0.3

"".*«'

I. O

.7

.6
. o
.6

I. 0

•7

I. 2

None

Percentage of magnesium in magne-
sium sulphate plus calcium sul-
phate:

/ 5 = 4
S'4
/ 5:4
5J4

{ 5 = 4

\ 5-4

(5:4

i:

. OOI

Percentage of magnesium in magne-
sium chlorid plus calcium chlorid :

O I

.01

. OOI

-54

/ 5H
I 5:4

(5:4
I 5:4
/ 5:4
I 5:4

212
213
214

215

216

217

218

3-5

il

5.8

3-3
6.8
4.2

1.6
2-5

4- 7

4.0

i- 5
7-8

2.6

230
23I

232

233
234
235
236

2-7

3-6
3-5

2. 9

i

7.6

Percentage of magnesium in magne-
sium carbonate plus calcium car-
bonate :

o 01 t . . .

July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 609

In Table XIV pots 2 05, 208, 210, 212, 213,216, 218, and 220 were har-
vested 53 days after planting. Their duplicates were permitted to grow
12 days longer. Pots 221, 223, 226, 227, 229, 232, 235, and 237 were
harvested at maturity, 80 days from the time of planting. Duplicates
were grown only 53 days. The analyses are given in Tables XV and XVI .

TABLE XV. — Analysis of straw of -wheat grown with sulphates, chlorids, and carbonates
of calcium and magnesium — series L

SULPHATES

Pot No.

Substance added.

Composition of plants.

Molecular
ratio o?
calcium
to magne-
sium.

Calcium.

Magne-
sium.

Calcium.

Magnesium.

203

O. 222

. 022
. 002

O. I
. OI
. 001

Mgm.
18.48
26.6

I5.2

Per cent.
0.77
.70
.40

Mgm.
15-45
38.86

5-73

Per cent.

o. 644
•97
•151

5: 6.9

S'^-S
5: 3-i

205
208

2IO

78 e

362

o 66

276

f: £|

213

. 002

. 001

22.36

•43

9-05

.174

5: 3-3

CAR

BONATES

216
218

. 022
. OO2

. 01
. OOI

9.24
17. 28

.28
• 432

20.33

is. 68

.616

5:i8-3

C* 7 C

220

5-31

•253

2.58

.123

5= 4

The plants used in the experiments in Table XV were harvested when
53 days old.

TABLE XVI. — Analysis of soybean hay grown with sulphates, chlorids, and carbonates of
calcium and magnesium — series M

SULPHATES

. O22

. OI

41. 89

.88?

3i. 4?

.642

o~-t
<r6. 2

. OO2

. OOI

21. 24

• SO

12. 24

• 34

c-4. 8

CH

LORIDS

228
230
231

. 222
. 022
. 002

. I
. 01
. OOI

15-39
25.11
13.89

•733
•93
• 386

13.96
19-54
10. 26

•665
.724
•285

S:?- 5
5:6.4
5:6.1

CAR

BONATES

. O22

. OI

27. 26

• 94

23. 92

.825

5-7- 3

235

. 002

. OOI

72.13
7. 1C

1-145

. ee

38.36

4. 04

.609
• 311

5:4-4
5-4-7

6io

Journal of Agricultural Research

Vol. VI. No. 16

EFFECT OF MAGNESIUM AND CALCIUM IN CALCAREOUS SOIL, DOLOMITE,
AND MAGNESITE, AFTER ALFALFA, UPON SOYBEANS (SERIES N)

The soybeans in series N were grown after three crops of alfalfa had
been removed and the roots turned under. Pot's 239 and 240 showed
but a small amount of growth. Pots 251, 252, and 253 showed consider-
able organic growth, but the plants were sickly and did not yield much
seed. The yields are reported in Table XVII. Analyses of the plants,
Table XVIII, show treatments with the largest quantities of magne-
sium in magnesite, giving the plants with the greatest magnesium con-
tent and containing as much as 29.92 pounds of magnesium per ton.
Also proportionately the highest amount of calcium and magnesium
were found in these pots. The check pots, 239 and 240, showed the
lowest percentage of calcium and magnesium in the plants grown.

TABLE XVII.— •- Yields of soybeans (in. y/u/«o pc, Vu>, un u*. «^n
alfalfa in soil, magnesite, and sand — series

Treatment.

Molecular
ratio of
calcium
to mag-
nesium.

Soybeans, series N.

Pot No.

Tops.

Roots.

Seeds.

None

Percentage of magnesium in calcareous
soil:

2.64

i. 328

/
1

/ 5:3-8
1 5:3.8
/ 5:3.8
j 5:3.8
/ 5:3.8
1 5:3-8
[ 5:3-9
I 5:3-9

( S'4
j 5-4

/ 5:i25
1 5:125

575

239
240

241
242

243
244

245
246

%

249

250
252
253

251

254

J-3
i. 6

5-6
7-3

1.1

8-5
6. i

12. I
' 6.5

6.6
6.6
3-8

8-5

4.0
3-8

0.6

I. 2

2.51

672

I. 2
I. O

2. 2

4-59
6-95

1.84

. 344

Percentage of magnesium in magnesite
plus calcium carbonate :

10

2. O

•7

Percentage of magnesium in magnesite :
06

•7
• 7

Percentage of magnesium in dolomite
C3:

Pots 240, 242, 244, 245, 247, 249, and 253 were harvested at maturity,
or 80 days after planting.

The plants used in the experiments in Table XVIII were 53 days old.

Table XIX shows the differences in .composition of wheat grown under
the same treatment but harvested at different periods of growth. The
first plants were harvested 53 days after being planted. It was the
original plan to allow the duplicates to mature, but owing to attacks of
mildew they were harvested 1 2 days later.

July i7, 1916 Influence of Calcium and Magnesium on Plant Growth 61 1

TABLE XVIII. — Analysis of soybeans grown after alfalfa in soil, magnesite, and sand —

series N

Pot No.

Substance added.

Composition of plants.

Molecular
ratio of
calcium
to mag-
nesium.

Calcium.

Magnesium

Calcium.

Magnesium.

27O

Per cent.
o. 014
5-78
2.897

1-455
•732
4-44
.666
.666
20.47

Per cent.
0. 016
2.64
1.328
.672
-344

2. 0

6.0

10. 0

12.7

Mgm.
7-02
109.76
131.0
90. 28
76.62
82.83
29.04

3^83
46.96

Per cent.
0-54
I.96
1.82
I.48
1.225
1.225
.726
.864
1.236

Mgm
4.6
41-5

Sis

48.42
76.54
39-40
56-85
31-73

Percent.
0-354
741
732
785

745
i 19

-985
1.496

-835

5'- 5-4
5'- 3-i
5: 3-3
5: 4-4
5: 5-1
5: 7-9
5:n-3
5 = 14- 4
5: 5-6

246

248

2 CQ

2<?2

The percentages of calcium and magnesium were greater in the plants
harvested in the earlier stages of growth. In the wheat the proportion
of magnesium to calcium was somewhat greater in the later stages of
growth. Still it must be remembered that the plants were by no means
thoroughly matured. This was not the case with the soybeans, as is
shown by Table XX. Soybean plants at maturity, or 80 days after
planting, showed higher percentages of calcium and magnesium than at
the end of 53 days of growth, except the checks in sand and those having
had extremely small applications.

TABLE XIX. — Composition of wheat at different stages of growth

Treatment.

Wheat 53 days old.

Wheat 65 days old.

Pot No.

Calcium.

Mag-
nesium.

Molecular
ratio of
calcium
to mag-
nesium.

Calcium.

Mag-
nesium.

Molecular
ratio of

to mag-
nesium.

None
Percentage of magne-
sium in dolomite €3:
12.7

173
179

177

175

203
205
207

209
211
213

215
217
2I9

0.44

•54

:il3

•77
.70
.40

^

•43

.28
•432
•253

o. 127

•599

I. 002
•8lS

.644

•97
•151

$

.174

.616
•392
. 123

5: 2.4
5: 9.2
5:16.9

5- 9-9

'5: 6.9

5:"-5
5= 3-i

f;*i

5: 3-3

5:18.3
5: 7-5

5: 4

0-135

•455

•3°5
•445

.61
.40
•255

•984
•30

• 245

• 405
•455

• *s

0.14
.418

•765
.783

•54
.646
• 158

.604

&

•587
• 316
.16

5: 7-i
5: 7-6

5:21
5:14.6

5= 7-3
5:i3-4
5: 5-i

I;i«

5: 5-5

5:"

5: 5-8

5: 8.8

Percentage of magne-
sium in magnesite:

10

2

Percentage of magne-
sium in magnesium
sulphate :

o. 01

o. ooi
Percentage of magne-
sium in magnesium
chlorid:

O I

O OOI

Percentage of magne-
sium in magnesium
carbonate:

0. 01
0. OOI

None

612

Journal of Agricultural Research vol. vi. NO. 16

Seissl (32) experimented with a large number of plants in various
stages of growth and found a slight fluctuation in the ratio of calcium
to magnesium in the ash analyzed in the different years. In nearly
every instance there was a progressive increase in the ratio of the lime
to the magnesia content towards autumn. In only two cases was the
lime content greater than that of the magnesia.

TABLE XX. — Composition of soybeans at different periods of growth

Treatment.

Pot No.

Soybeans 53 days old.

Soybeans 80 days old.

Calcium.

Mag-
nesium.

Molecular
ratio of
calcium
to mag-
nesium.

Calcium.

Mag-
nesium.

Molecular
ratio of
calcium
to mag-
nesium.

None

181
187

31

221
223
225

227
229
231

233
235
237

241
243

245
247

239

249

252

Per cent.
0-344

1.546
.96

1-357

1.19
.855
•59

•733

:39i6

• 94
I- 145

•55

i. 96
1.82

1.48
1.225

•54

1-255
.864

Per cent.
0.449

.964

1.032
.838

I. 21
.642

•34

-665
.724
.285

.825
.609
-3"

.741
•737
.785
•745
•354

1.19
1.496

5:10.8

5: 5-2

5: 9

5: 5-2

5: 8.4
5: 6.2
5: 4-8

5: 7-5
5: 6.4
5: 6.1

5= 7-3
5: 4-4
5: 4-7

5: 3-i
5: 3-3
5-' 4-4
5: 5- I
5- 5-4

5: 7-9
5:i4-4

Per cent.

o. 29

2.07

•75
I-I5

1.71
*&

2-55
•65
.27

1-13
'•57
•36

3-o

3-65
2.7

2. II

•17

i-55
i. 145

Per cent.

o. 28

1-3

I. 138

.815

2. 28

K3*

•356

i-33
•495

•255

1.19
•399
.184

•997
1.26
i. 016

•79
.118

i-55
2. 1 66

5: 8
5-' 5-2

5:12.6
5: 5-9

5:11.1

5: 9
5: 4.8

5: 4-3

5: 6.3
5: 7-9

5: 8.7

5: 2.1

5= 4-2

5: 2.77
5: 2.87

5: 3-i
5: 3-i
5= 9-2

5: 8.3
5:i5-75

Percentage of magnesi-
um in dolomite €3:
12 7

Percentage of magnesi-
um in magnesite:

2

Percentage of magnesi-
um in magnesium sul-
phate:

O.I

OI

.001. . . . .

Percentage of magnesi-
um in magnesium
chlorid:

.001 1 ...

Percentage of magnesi-
um in magnesium car-
bonate:

O.OI
.001

None

Percentage of magnesi-
um in calcareous soil :
2 64

*-3*
672 .

344

None

Percentage of magnesi-
um in magnesite:

2

io

July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 613

TABLE XXI. — Tolerance of crops for calcium and magnesium

Wheat.

Alfalfa.

Treatment.

ratio of
calcium
to mag-
nisium.

Calcium.

Mag-
nesium.

Molecular
ratio of
calcium
to mag-
nesium.

Calcium

Mag-

nesium.

Molecular
ratio of

to mag-
nesium.

None

o 187

o 108

Percentage of magne-
sium in dolomite
Ci:

O 2

e-4. 8

208

271

T 7 6

o 6

T4. 8

^86

Percentage of magne-
sium in brown-gray
silt loam:

206

2^6

708

r*2 2

Percentage of magne-
sium in dolomite

C3:
12.7

5*5* 2

. 574

. 730

5: 12. 6

i. 068

• 711

5:5. 5

Percentage of magne-
sium in magnesite:
10

S-*I25

• 375

• 955

5:21

i. 381

I. OO

5:6

The yields in the pots in Table XXI were practically the same on the
different treatments. This shows the alfalfa to contain more calcium
and magnesium than the wheat. Some of the other treatments show
higher percentages of calcium and magnesium, but the yields are not com-
parable. It might be interesting to note that soybean hay at maturity
contained per ton as much as 73 pounds of calcium and 25.2 pounds of
magnesium when grown in a mixture of equal parts of sand and calcareous
soil,, but when grown in a mixture containing 40 per cent of magnesite

there were 22.9 pounds of calcium and 43.3 pounds of magnesium per ton.
f

DISCUSSION

The experiments reported here extend over a period of three years
(1912 to 1915) and include approximately 300 pot cultures and upwards
of 300 duplicate determinations of calcium and magnesium.

Difficulty was experienced in finding a medium that was free from
calcium and magnesium, and which would still approach soil conditions.
Attempts were made to grow plants in aluminum turnings but without
success, probably due to the formation of some aluminum salts when the
plant foods were added. It is well known that aluminum salts disturb
the physiological functioning of plant organs.

Wheat and cowpeas grown in granular paraffin without the addition
of calcium and magnesium showed in the total plant only an amount
equal to that furnished by the seed.

6 1 4 Journal of Agricultural Research vol. vi, NO. 16

The difference in the medium in which the plants were grown caused
different effects upon the plants. Brown silt loam was a better medium
than sand when treated with chemically pure magnesium carbonate, even
though it already contained 25 times as much calcium and magnesium
as did the sand. Still sand would have an ameliorating effect when com-
pared with solution cultures. Jensen (10) found that in quartz sand a
much higher concentration of salts was required to cause death than in
water cultures.

As previously shown under literature studies it is quite generally
believed that plants have to some extent a selective absorption. The
results here seem to indicate such a condition, for the dolomites used
tend to go into solution in a molecular ratio, but the plants failed to take
them up in this ratio. The tendency of the plants under these conditions
was to take up relatively larger molecular proportions of magnesium than
of calcium. Analysis of the plants show that they do not necessarily
take up calcium and magnesium in the same ratio as applied, as, for
example, in dolomite €3 the ratio of calcium to magnesium is 5:5.2,
whilg the plants may and do take it up in a ratio of 5 : 7 or 5 :3-95.

In the case of the addition of 25 per cent of magnesite the ratio of cal-
cium to magnesium was 5 : 125, while in some of the plants grown in such
treatment the ratio varied from 5:15 to 5:21. Wheat grown in soil
treated with 6 per cent of dolomite showed in the tops a ratio of 5:9.1
and in the roots a ratio of 5 : 4. 3 5, or for the whole plant a ratio of 5 :6.3,
while in dolomite Ci it was 5:4.8. Alfalfa grown in the same treatment
showed for the entire plant a ratio of 5:4.2, but when grown in soil
treated with dolomite €3 the ratio for the total alfalfa plant was 5:
3.95, while in the dolomite the ratio of the calcium to the magnesium
was 5: 5. 2.

The chlorids of calcium and magnesium were more detrimental to
wheat and soybeans than were the sulphates at concentrations up to
o.i per cent of magnesium. This amount of magnesium in the prepared
carbonate entirely inhibited growth, whereas lower concentration gave
better growth than either the sulphates or chlorids.

Wheat 65 days old showed smaller percentages of calcium and mag-
nesium than did similarly treated wheat at 53 days of growth, but the
total amount of these two elements in the plants increased with the
duration of growth.

Soybeans at maturity, or 80 days after planting, showed for the hay
higher calcium and magnesium contents than at 53 days of growth,
except in the case of the checks and those treated with extremely small
quantities. Some of the samples showed as much as 73 pounds of cal-
cium and 25.2 pounds of magnesium per ton when grown in a mixture
of one-half sand and one-half calcareous soil, but when grown in soil
containing 35 per cent of magnesite there were 22.9 pounds of calcium

July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 615

and 42.3 pounds of magnesium per ton; whereas the checks contained
5.8 pounds of calcium and 5.6 pounds of magnesium.

Whenever excessive amounts of magnesium were applied, there was
a characteristic appearance of yellow leaves. The uppermost leaves be-
came yellow and gradually died, while the lower leaves remained green.
This condition is characteristic of magnesium sickness and just the re-
verse of the effects produced by translocation processes.

The general tendency is for the percentages of calcium and magne-
sium in the plants to increase with the increase in size of application.
Likewise a high magnesium content in the plant tends to accompany
plant sickness, as sickly and healthy leaves fromxthe same soybean
plant showed, respectively, i.n per cent of magnesium as against
0.88 per cent magnesium.

All varieties of the seed used contained more magnesium than cal-
cium, while ordinarily the remainder of the plant contained more cal-
cium than magnesium. This conforms with the data of Schulze and
Godet, who report more calcium in the husk and more magnesium in
the seed.

Nitrogen was applied to the legumes as well as to the cereals, so as
to be sure that this was not the limiting factor.

In a number of instances the differences in the yields between dupli-
cates were as great as between the different treatments. At several
periods during the growth of the plants parasites -caused injuries, some-
times great enough to necessitate harvesting the crop.

CONCLUSIONS

(1) Wheat, soybeans, alfalfa, and cowpeas grew normally either in
96 per cent of dolomite and 4 per cent sand, 100 per cent of magnesian
limestone, or in sand containing 7 per cent of magnesite.

(2) Dolomite up to 40 per cent proved beneficial to plant growth.
These results indicate that dolomite and magnesian limestone will not
be detrimental as applied in agricultural practices.

(3) Applications of prepared magnesium carbonate up to 0.7 per cent
caused no injury in brown silt loam, but 0.35 per cent prevented the
growth of all plants tested in sand.

(4) The crop yields and the ratio of calcium to magnesium- in the
plants bear no direct relation to the ratio in the natural carbonates
applied.

(5) Different ratios of calcium to magnesium within rather wide
limits produced no marked differences in yields.

(6) Increasing the size of applications increased the calcium and
magnesium content of plants.

(7) A tolerance of calcium and magnesium occurred in all varieties
of plants grown. With approximately identical yields, wheat straw

616 Journal of Agricultural Research vol. vi, NO. 16

grown in sand, brown silt loam, dolomite, and soil containing 35 per
cent of magnesite showed calcium contents varying between 0.165 Per
cent and 0.547 per cent and magnesium contents varying between 0.132
per cent and 0.955 Per cent.

(8) Acid extractions failed to remove all the calcium and magnesium
from the sand. There remained after the various extractions from 768
to 852 mgm. of calcium and from 540 to 960 mgm. of magnesium per
6,000 gm. of sand.

(9) The plants possessed a decided ability to obtain calcium and mag-
nesium from sand extracted with strong hydrochloric acid, as borne
out by the following example: Three crops of alfalfa removed from acid
extracted sand 164.43 mgm. more calcium and 90.4 mgm. more magne-
sium than was contained in seeds similar to those planted.

LITERATURE CITED

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(3) GILE, P. L.

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(5)

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(6) G6SSEL, Fr.

1904. Importance of calcium and magnesium salts for plants. (Abstract.)

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(8)

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July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 617

(n) KEARNEY, T. H., and HARTER, L. L.

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(13) LEMMERMANN, O., EINECKE, A., and FISCHER, H.

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(14) LIPMAN, C. B.

1909. Toxic and antagonistic effects of salts as related to ammonification by
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(15) LOEW, Oscar

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(16) -

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(17) MacDouGAL, D. T.

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(18) MaclNTiRE, W. H., WILLIS, L. G., and HARDY, J. I.

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(19) MEURER, Reinhard.

1909. Ueber die regulatorische Aufnahme anorganischer Stoffe durch die
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(20) MEYER, D.

1904. Untersuchungen iiber die Wirkung verschiedener Kalk- und Magnesia-

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(22) NAKAMURA, T.

1905. Uber die Wirkung einer starken Magnesiadimgung in Form von Bitter-
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(23) NATHANSON, Alexander.

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(24) OSTERHOUT, W. J.

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(25) PATTERSON, H. J.

1900. The occurrence and composition of lime in Maryland, together with a
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(26) PEIRCE, G. J.

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(27) PFEFFER, W. F. P.

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(28) PISCIOTTA, F.

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(30) RussEUv, E. J.

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(31) SCHULZE, Ernst, and GODET, Ch.

1908. The amounts of calcium and magnesium in plant seeds. (Abstract.)

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(32) SEISSL, J.

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(33) STEWART, Robert.

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(34) ULBRICHT, R.

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1911. The variation of plants under the influence of lime and magnesia.

(Abstract.) In Exp. Sta. Rec., v. 26, no. i, p. 35-36. 1912. Original
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PLATE LXXXIV

Fig. i. — Growth of wheat in sand containing varying quantities of calcium and
magnesium. The small growth of wheat in the pot marked "6% magnesium" is
due to a detrimental physical effect.

Fig. 2. — Growth of alfalfa in sand containing varying amounts of calcium and
magnesium. «,

(620)

Calcium and Magnesium and Plant Growth

PLATE LXXXIV

Journal of Agricultural Research

Vol. VI, No. 16

Calcium and Magnesium and Plant Growth

PLATE LXXXV

Journal of Agricultural Research

Vol. VI, No. 16

PLATE LXXXV

Fig. i. — Growth of soybeans following a crop which had already absorbed most of
the readily available calcium and magnesium.

Fig. 2. — Growth of soybeans in soil treated with magnesium. Note the sickly
appearance of the top leaves in the right-hand pot, which is characteristic of treatment
with large quantities of magnesium.

PLATE LXXXVI

Fig. i. — Comparative growth of soybeans in brown silt loam and dolomite, showing
that the loam would have been improved by the addition of some limestone or
dolomite.

Fig. 2. — Soybeans in sand treated with magnesium, showing that their growth
increases inversely with the quantity of magnesium applied as sulphate.

Calcium and Magnesium and Plant Growth

PLATE LXXXVI

Check
Sand only

Journal of Agricultural Research

Vol. VI, No. 16

Calcium and Magnesium and Plant Growth

PLATE LXXXVII

Journal of Agricultural Research

Vol. VI, No. 16

PLATE LXXXVII

Comparative root production of wheat grown in the chlorids, sulphates, and car-
bonates of magnesium and calcium. Root growth is inversely proportional to the
amount of salt applied.

PLATE LXXXVIlt

Fig. i. — Comparative growth of wheat in sand and in dolomite. The dolomite con-
tained 96 per cent of carbonates of calcium and magnesium and 4 per cent of insoluble
silica residues.

Fig. 2. — Comparative growth of wheat in magnesium chlorid and magnesium
sulphate.

Calcium and Magnesium and Plant Growth

PLATE LXXXVIII

4 * SAND \

: and RF.
** 96% DOL.

Journal of Agricultural Research

Vol. VI, No. 16

Frank Archibald Wyatt was born February 22, 1887. His ele-
mentary education was secured in the public schools of Utah. Sep-
tember, 1904, he entered the preparatory department of the Utah
Agricultural College and graduated from that institution in June,
1910, with the degree of Bachelor of Science. He immediately received
an appointment as assistant in extension at the Utah Experiment
Station.

In September, 1911, he entered the University of Illinois as a
special student. During the school year 1912-13 he pursued graduate
work in Agronomy at this institution, and received the degree of Master
of Science in June, 1913. He was a fellow in Agronomy in the Uni-
versity of Illinois from 1913 to 1915.