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DEPARTMENT BULLETIN NO. 1379 SQ #6

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Washington, D. C. v January, 196.

ELECTROCULTURE

By Lyman J. Briaes,! A. B. CampsBeti, R. H. Heap, and L. H. Fuint, Office
: of Biophysical Investigations, Bureau of Plant Industry

CONTENTS
Page Page
Normal electrical state of the atmosphere _- - - 1 | Summary of experiments at Arlington Ex-
Electrical field employed in electrocultural Peument Harm. 25-22 Sot Se Pe ee 15
ou DATOS cS RNS eee ek eee ee 2 | Review of other investigations in electrocul-
Electrocultural experiments with miscel- utes £455 0a Wd ne ie OE) St 17
SEO HSIChOpSee Ae Wet! are bk eS 3 Experiments with soil currents__________ 17
Electrocultural field experiments with grains_ 4 Experiments with modified potential
Electrocultural experiments in the plant PrAGIEN TSM. Sass he APS eee Pea 21
LTTE Sub 22a ee eS eee ek es Oe eee Issue tteravure citeda 7 lee A ALA ee 32

The term “‘electroculture’’ as used in this bulletin refers to practices
designed to increase the growth and yield of crops through electrical
treatment, such as the maintenance of an electric charge on a net-
work over the plants or an electric current through the soil in
which the plants are growing. 7

During the past 75 years many experiments in electroculture have
been carried out with varying degrees of refinement. Some of these
experiments indicate that the yield of crops can be materially in-
creased by electrical treatment. Others, conducted along similar
lines, fail to show any marked response to the treatment. In this
latter class are included the experiments conducted by the Office of
Biophysical Investigations of the Bureau of Plant Industry, which
are reported in the following pages. This report is followed by a
brief account of other investigations in this field. Investigations
relating to the cultivation of plants under electric lights are not in-
cluded in the review of the literature of electroculture, the response
of the plants under such conditions being due primarily to the heat
and light into which the electrical energy has been transformed.

NORMAL ELECTRICAL STATE OF THE ATMOSPHERE

Since the effect of using a charged network over growing plants is
to change the electrical state of the atmosphere surrounding the plants
it seems desirable to discuss briefly the normal electrical conditions in
the atmosphere and the changes produced by the charged network.
An examination of the electrical conditions in the atmosphere over
an open field on a clear day shows that there is a force tending to
move a positively charged body downward; in other words, the
electrical field of force is identical with that which would exist if the
earth were charged negatively.

1 Physicist, Bureau of Standards, since 1920.
62149°—26;——1

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9 BULLETIN 13879, U. 8. DEPARTMENT OF AGRICULTURE

On fine days, the potential gradient in the atmosphere is almost
invariably positive in sign (that is, a positive charge tends to move
downward), and the magnitude of the vertical gradient is of the order
of 100 volts per meter, though it is continually varying. When thun-
derstorms are in the neighborhood, the potential gradient may be
either positive or negative and changes sign frequently. The magni-
tude of the potential gradient also undergoes wide fluctuations,
during stormy weather frequently attaining values of 10,000 volts
per meter, 100 times the normal gradient.

A further examination of the lower atmosphere shows that charged
particles or ions are always present. Both positive and negative
ions are found, the positive ions generally being. somewhat more
numerous. They consist of groups of molecules loosely bound
together and carrying a charge. Frequently these small ions attach
themselves to dust particles, thus becoming large ions, which move
much less rapidly thes the small ions.

When the potential gradient is positive, the negative ions move
upward and the positive ions downward to the ground, thus con-
stituting an electric current flowing from air to earth. This current
is due almost entirely to the small or free ions, the mobility of the
large ions being so low that their influence on the conductivity of the
air can be disregarded. The magnitude of the current from the air
to a unit area on the earth’s surface is extremely small, being only
2xX10°-"% amperes per square meter or 5X10 °° amperes per acre.

The strength of the current is proportional.to the potential gradient, °
to the number of ions per unit volume, and to their mobility. The

average number of free ions is of the order of 1,000 per cubic centi-
meter, the positive ions constituting somewhat more than one-half
the total number. Their mobility is such that they migrate with a
velocity of about 1 centimeter per second when subjected to a poten-
tial gradient of 100 volts per meter. )

Although the air-earth current per unit area is extremely small,

it is sufficient when applied to the whole of the earth’s surface to

reduce the negative charge of the earth to one-half its initial value in
about 10 minutes. The explanation of the maintenance of the
negative charge of the earth under such extraordinary conditions is
one of the outstanding problems in atmospheric electricity (12, 47),

ELECTRICAL FIELD EMPLOYED IN ELECTROCULTURAL EXPERI-
MENTS

In most of the field experiments conducted at the Arlington
Experiment Farm, the standard height of the network was 5 meters,
and the potential of the network was approximately 50,000 volts.
The average potential gradient under the network was therefore of
the order of 10,000 volts per meter, or about 100 times the normal
gradient in fine weather. This would produce an air-earth current
about 100 times the normal current as long as the ion content of the
air remained normal. However, a marked ionization occurred at the
network, so that the number of positive ions per unit volume under
the network was much higher than normal. This was shown by
means of measurements made when the network was charged and a
gentle breeze blowing. On the windward side of the network the
conditions were normal, but on the leeward side a decided increase

2 The serial numbers (italic) in parentheses refer to ‘‘ Literature cited,’’ at the end of this bulletin.

ELECTROCULTURE 3

was observed in the ion content of the air which drifted from under
the network. This effect could be traced to a distance of several
hundred feet from the network.

The principal change in the environment of plants grown under a
charged network appears then to consist in a marked increase in the
strength of the air-earth current which flows through the plants to
the ground.

If the drifting charge from the experimental plat should pass over
the control plat, it would increase the air-earth current to the control
plat to some extent, owing to the increase in the number of ions per
unit volume. But even under such conditions the current flowing
into the control plat would necessarily be small in comparison with
that flowing into the experimental plat, since both the ion content
and the potential gradient are much higher under the network and
the current is proportional to the product of these factors.

ELECTROCULTURAL EXPERIMENTS WITH MISCELLANEOUS CROPS

Experiments in 1907 —Electrocultural experiments were first under-
taken by the department * in 1907, using vegetables for the most
part as test crops. The test plat, which was 138 by 106 feet, was
divided into three sections 44 by 106 feet, the center section being used
as the experimental area and the two outside sections as controls.
The crops were planted in continuous rows across the three sections,
so that the center third of each row was under treatment.

A Wagner mica-plate electrostatic machine was used as a high
potential source. It was inclosed in a tight case, permitting the use
of drying agents to keep the machine in the best condition for opera-
tion. The positive pole was connected to an open wire network
strung on glass insulators, and the negative pole was grounded. The
network covered the experimental plat and was placed high enough
to permit the use of a horse cultivator. The applied potential varied
somewhat with weather conditions, but usually exceeded 50,000
volts. The network was charged throughout the night, from late
afternoon until early morning. The plants were subjected to the

- electrical treatment 656 hours in all, extending from June 20 to

September 16. The yields are shown in Table 1.

TasBLe 1.—Yields following electrocultural treatment of miscellaneous crops under
test at Arlington Experiment Farm in 1907

Yields per plat (pounds)

| Ratio of
| treated

Crop i Control to
Experi- | Average average

mental |— of of

Plat Plat A | Plat C | Controls | controls

0 ee as Pe ae ee eee Oe eee | 128, 25 119. 75 138. 75 129. 25 0. 996
Cowpeas-_- =~ iveet® A ae eee eee 20. 60 | 19. 14 24. 25 21. 70 | . 95
OE UT Sc as ae is ee ne Ge 30.9 40. 14 43. 0 41. 57 . 742
OF ie ee a 44.0 52.0 39. 0 45. 5 . 968
en nd ah A SBE DBD ote eee 20 ee 55. 0 45.0 64. 0 54.5 1.01
tT 1. 1 So ee 24. 0 25. 0 25. 0 25. 0 . 96
DAL ota ee ee ee 15. 0 18.0 17.0 17. 5 . 856
5 Stl 2 oe, 2 ee eee ee eee 106. 05 106. 0 80. 0 93. 0 1.14
EDT Set ea ry ee eee 20. 0 25. 0 23. 0 24.0 . 835
oe ee cl toe SY SRS ee eee ee eee 8.5 10.0 11.5 10. 75 | . 790
}

* These experiments were conducted on the Arlington Experiment Farm by the Office of Biophysical
Investigations and the Office of Crop Physiology and Breeding Investigations, the field work being handled
largely by E. W. Hudson and W. Seifriz.

SS a ee ee

4 ' BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE .

The lack of uniformity in the yields of the control plats A and C in
the 1907 experiments (‘Table 1) is such that no great dependence can
be placed in these results. It is significant, however, that in only one
of the 10 trials recorded did the treated plat show any evidence of a
substantial increase in yield when compared with the mean of the
contro] plats.

Experiments in 1908.—In the 1908 trials the wires were run di-—
rectly over the treated rows and kept at a height of 6 to 18 inches
above the plants by means of adjustable brackets on which the
insulators were mounted. The control rows ran parallel to the
treated ones at a distance of 614 feet and were separated from them
by intermediate guard rows.

In one part of the plat the wires over the plants were charged
posuney to about 50,000 volts from 4 p. m..to 7 a. m. each day, 955

ours in all. In the other part of the plat the wires were charged
and discharged rapidly by connecting them to one terminal of the
secondary of an induction coil, the other terminal being grounded.
In this case the potential rose to about 20,000 volts and then dis-
charged suddenly through a small spark gap between the wires and
the ground.

The treatment first described is similar to that employed by Lem-
strém and believed by him to result in increased sane In these
experiments, however, neither treatment gave any evidence of in-
creased growth. The detailed yields consequently are not of special
interest.

ELECTROCULTURAL FIELD EXPERIMENTS WITH GRAINS

In selecting a location for the electrocultural field experiments near
Washington, three conditions were sought: (1) A uniform soil, (2)
available electric power, and (3) accessibility from the laboratory in
Washington, since the equipment had to be visited daily during the
experimental season. Soil uniformity is particularly difficult to find
in the environs of Washington, and the Arlington Experiment Farm
forms no exception in this respect. It seemed to be the best avail-
able location, however, and portions of sections A, B, and E were
made available for the experiments, which were carried on from 1911
to 1918. Sections A and B proved very disappointing witheregard
to their uniformity, and the most reliable results were obtained in
section E. These experiments will be first described.

The Lodge-Newman apparatus used in the experiments from 1912
to 1915, inclusive, was designed in England primarily for electro-
cultural work and consists essentially of a 110-volt induction coil,
operated by a mercury interrupter, and a rectifier. Five Lodge
valves * designed to rectify the ee ensen alternating current were
placed in series with the network, thus allowing only the positive
impulses from the secondary of the coil to reach the network (33).
The negative pole was grounded. Two balls 25 millimeters in diam-
eter, one of which was grounded and the other connected to the net-
work, were used to determine the potential, assuming a breakdown
gradient of 3,000 volts per millimeter. :

Systematic measurements of the current from the network were
not made, but the current could be determined approximately from
the potential of the network and the known power characteristics of

4 For a description of the valves, see Lodge, O. (34).

ELECTROCULTURE 5

the machine used. The current from the network over the experi-
mental plat in section E was of the order of 0.1 to 1 milliampere per
acre, depending on the voltage and network used. This is of the
order of 10,000 to 100,000 times the intensity of the normal air-earth

current.
EXPERIMENTS IN SECTION E

It has been shown by Jgrgensen and Priestley (26) that the ioniza-
tion from the highly charged network is by no means limited to the
area beneath the network, but may be carried by the wind to a con-
siderable distance, depending on the weather conditions. It was
consequently deemed advisable to separate the treated and control
plats so far as practicable. Accordingly, two plats of half an acre
each (132 by 165 feet) were selected in section E which were sepa-
rated by a distance of 350 feet, one plat being directly north of the
other.

Fic. 1.—General view of the experimental field at Arlington Experiment Farm, showing the
system of double insulators used in suspending the wire network from poles and the power lines
leading to the motor in the apparatus house (foreground). Poles supporting the grounded net-
work along the side of the control plat may be seen in the distance. (Photographed May 8, 1918.)

The rye which was growing on the plats of section E when they
were selected in 1913 was cut and weighed. The results show that
the productiveness of the two plats was about the same, being as
follows: Yield of south plat, 2,438 pounds; of north plat, 2,499 pounds;
ratio of south plat to north plat 0.98.

Experiments in 1914.—A network 16 feet high was erected over the
south plat, having cross wires at intervals of 15 feet. (Fig. 1.)
Winter wheat was sown on both plats the following October, and the
treatment was given by means of the Lodge-Newman apparatus,
which furnished a positive charge to the network at a potential
ranging from 30,000 to 60,000 volts. The treatment was given in
the fall and spring from 3 to 7 p. m., a total of 336 hours. The grain
was harvested in June, 1914, giving yields which were substantially
the same for both plats, as shown in Table 2.

6 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

TABLE 2.—Yields of winter wheat on plats following electrocultural treatment (posi-
tive charge), section E, Arlington Experiment Farm, in 1914

Yields (pounds) Ratio of treated

to control
Plat Lao 2 a
Shock Grain Shock Grain
Treated ee a SE a a a ea ee 2, 332 644. 8 \ alt 02 0. 97

Gimmes 0) bE eee ee 3g A So pe ae oe): Se oe eee ees | 2, 281 656. 5

Experiments in 1915.—Wheat was again sown in the autumn of
1914. The fall treatment was omitted, owing to bad weather. In
1915 the network was charged positively by the Lodge-Newman
apparatus twice a day from 4 to 7 a. m. and from 5 to 8.30 p. m., a
total of 345 hours. The distance between the cross wires of the net-
work this year was 6 feet. The plats were divided at harvest into
east and west halves. The yields are shown in Table 3.

In both plats two bad spots developed on the western halves, in
which the grain was much poorer than the average.

_ TaBLe 3.—Yields of winter wheat on plats following electrocultural treatment (posi-

tive charge), section E, Arlington Experiment Farm, in 1915

Plat Yields (pounds) megs re
a

| Shock | Grain | Shock | Grain

Eastern half:

G¥eatod. 2. 2). ee lee eres ae 832 321.5 oat
= eT ee oa 2: 822 350 \ 1.01 0, 92
Western half:
PURGAbOD So. 2 a ee Sf eet a ee | 716 303
Sete.) 222.2. de) aay ie | 540 254. 5 \ 1,32 1.19
Total: |
Treated: 22 55. .°15, a... ee 1, 548 624. 5 \ 114 1. 08

Control____- Bee on a SO en a nn a 1, 362 604. 5

yields are given in Table 4.

TABLE 4.—Yields of winter wheat on plats following electrocultural (negative)
treatment; section E, Arlington Experiment Farm, in 1916

Yields (pounds) | Ratio of treated
Plat
Shock Grain Shock Grain
ee eo 1, 324 347. 5
TOSCO Sone ee oe Be ee ee > :
Banitell... tL eee ai: See ele Eeinmen 1352 | | 411.0 \ 0. 98 0. 85
Western half:
pRreateGe loo 2 oon. oe AeA ee ee oe 1, 204 324. 5 \ 1.10 95
Wontral alts. 2 SACL ee ee 2 ee ee 1, 092 343. 0 . .
igi d 2, 528 672.0
PONUCG A. SS OE RS NSN Oe oe See ae eee . ,.
(ce Os aS ME AST <> SOREL zit | roof 108 ae

ELECTROCULTURE 7

Experiments in 1917.—Wheat was again sown in section E in
October, 1916, and allowed to mature the following summer without
treatment, as an additional check on the soil conditions. At time of
harvest in 1917 the plats were again cut into eastern and western
halves, the south plat being the one which had received the elec-
trical treatment in prévious years. The yields are shown in Table 5.

Comparison with the rye yields of 1913 shows that the south
(treated) plat apparently gained slightly in its relative productivity
during the five years, but the change is well within the errors of field

trials.

TaBLe 5.—Yields of winter wheat on plats without electrocultural ‘treatments,
é section E, Arlington Experiment Farm, in 1917

Ratio of south to

Yields (pounds) north plats

Plat
Shock Grain Shock Grain
reieey pr bated
TD SS Se oS ee ee ey ee ee: ae ee ee , 628. 580. 5
mers re Ge 1625.0; e3Loy 10 0.92
wiprncetagts 1, 562 0)
CEES athe ee ee 562. 5 557. 0 :
"i os Ses Se a5 aes eae eT 1) 439.5 567.5 +98 - 98
3: h pla 3, 19( 37.5
Jon fon LE Segoe tls ST mr 190.5 | 1,137.5 ;
MAMMA #257611 Jol iciiite oi.) 30-1) 3°064.5| 11985 f 1% - 95

Experiments in 1918.—In the fali of 1917 winter wheat (Currell)
was sown on the plats in section E, and in the spring a %-inch mesh
alvanized-iron screen 132 feet long by 15 feet high was erected 20
Feet south of the check plat. It was thought that the grounded
screen might protect the north plat from the drifting charge, but
later measurements show that it is of doubtful value.

The static machine was again used, with the positive pole con-
nected to the network. The number of cross wires was increased
to one every 3 feet. This increased the current and reduced the
potential of the network to about 30,000 volts.

Although the winter was exceptionally cold the stand in the spring
was excellent. Treatment was started April 15 and continued for
46 days from 4 p. m. to 8 a. m. each day, a total of 736 hours.

At harvest the eastern and western halves of each plat were kept
separate and weighed. The yields are shown in Table 6.

TaBLeE 6.—Yields of winter wheat on plats following electrocultural treatment (posi-
tive charge), section E, Arlington Experiment Farm, in 1918

vied pounasy | Fev ttre

Plat r oe
Shock Grain Shock | Grain
es
ee eee ee ee Moat 569 i
ete! 50000. 1) 332 518 1. 16 | 1.10
estern half:
SMR eet 1, 289 481 | 99 95
_ sk | LS CSRs Eye 1, 307 507 Jf esa
Total:
een ees oe ee ae iw i TT 2, 820 1,050 \ 1. 07 1. 02
| 07 . 02

iD Dae ALN aa ee eet 2, 639 1, 025

8 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

A general view of the experimental field as it appeared on May 8,
1918, is shown in Figure 1.

After the 1918 crop was harvested, measurements of the charge
carried by the wind were undertaken. A flame collector was used,
which was connected to the gold leaf of an electroscope, the case
being grounded. A full-scale deflection of 2% divisions represented
a potential of about 1,000 volts. ‘In all the measurements the
collector was held at a height of 1 meter above the ground. ~

A light south wind was blowing the day the measurements were
made. With no charge on the network, a very slight deflection of
the gold leaf could be noticed. With the network charged, however,
the full-scale deflection occurred very rapidly at any point under and
within 20 feet outside the network on all sides, even tothe south,
the direction from which the wind was coming. At 50 feet south,
only about 1 division deflection was obtained. North from the net-
work the deflection to full scale was slower and more irregular the
greater the distance from the network, and when only 2 feet south of
the screen along the south side of the north plat the maximum deflec-
tion obtainable was about 20 divisions. Just north of the grounded
screen the maximum deflection obtained was about 9 divisions. As
the collector was moved farther north from the screen and into the
control plat, the deflection again increased, until at the center of the
control plat it was off the scale again. The grounded screen along
the south side of the control plat thus afforded little protection from
the drifting charge. At a point 1,000 feet from the network, the
last point observed, a full-scale deflection was obtained. At all
points beyond 100 feet from the network over the south plat the
deflection was very irregular and unsteady.

The Weather Bureau records show that during the 46 days of
treatment in 1918 the wind was due south only 3 days. Owing to
the distance of 350 feet between the treated and control plats, the
wind would have to be nearly due south to carry any appreciable
charge over the control plat.

SUMMARY OF EXPERIMENTS IN SECTION E

The relative yields of the south (treated) and north plats in section
KE are summarized in Table 7.

TaBLeE 7.—Summary of yields of rye and winter wheat on the south (treaied) and
north (untreated) plats, section E, Arlington Experiment Farm, in six stated
years

Ratio of yields of Ratio of yields of
Treatment | South to north plats Treatment | South to north plats
Year Crop of south Year Crop of south
plat plat
Total Grain Total Grain
1913 | Rye. - INIOHOSL = | ORGS Re. seers | 1916 | Wheat__.| Negative___ 1. 03 0. 89
1914 | Wheat___| Positive____ 1. 02 0. 97 11,3) 7 (A 5 Ko ae Sa None-:.--- 1. 04 . 95
1915 Moz. =8 es (ee | 1.14 1. 03 OUST Atedore 2s Positive_-__- 1.07 1.02

It is evident from the summary that the electrical treatment did not
produce any sensible increase in yield. Anexamination of the detailed
results for 1915 shows that the somewhat higher ratios obtained dur-
ing this unfavorable year are due to a marked decrease in yield in

ELECTROCULTURE 8)

half of the control plat. Aside from this, there appears to be a gradual
increase in the total yield of the south plat relative to the north one,
irrespective of whether a positive charge, a negative charge, or no
charge at all was used. It is of interest to note that the grain ratios
with a positive charge on the network are all slightly higher than the
ratio in 1917, when no treatment was given; with the negative charge
the reverse is true. This seems consistent, for if increasing the posi-
tive gradient of the electrostatic field tends to stimulate growth, then
to reverse the sign of the field may perhaps tend to inhibit growth.
Opposed to this speculation is the fact that the negative field appar-
andly had no effect on the ratio of the total yields of the two plats.
In brief, while there is some evidence of a slight increase in grain
yield when wheat is grown under a network which is positively charged
to a high potential, the observed effect is so small that it is well within
the experimental errors of field trials. |

- EXPERIMENTS IN SECTION B

Experiments in 1911.—The first electrocultural field experiments at
Arlington Experiment Farm were made in 1911 with grains in sec-
tion B, employing a plat which had been seeded in strips to wheat
the previous fall. In the spring of 1911 a network of small wire was
installed over the eastern half of the plat, covering half of each
- variety. The network was 7 feet high with wires at intervals of 3
feet, connected to the positive pole of a static machine operating at
a potential of about 40 to 50 kilovolts. The machine was in opera-
tion six days a week from 3 p. m. to 7 a. m. except during rainy
weather from early spring to harvest.

Table 8 shows the relative yields of the treated and control halves.

TABLE 8.—Yields of winter wheat on plats following electrocultural treatment (posi-
tive charge), section B, Arlington Experiment Farm, in 1911

Yields per acre (pounds)

Ratio of
Fe grain,

Variety Treated half Control half Hantod te

control

Grain Straw Grain Straw
| aa

Bo UT) SS ake Soe A eee ee es ee ee eee 820 1, 740 780 1, 360 1. 05
anh z = oS WS gee ee ee en eee ee 1, 320 1, 920 1, 450 2, 070 .91
(bt Ib he cohen pea ee SR eee oe Re | 1, 240 2, 520 1300 2 Se «95

Experiments vn 1912.—In the fall of 1911 one variety of wheat,
Currell (Currell’s Prolific), was sown on section B, and the network
was again erected at the height of 7 feet with cross wires 3 feet apart,
as before. The treated and control plats each had an area of three-
fourths of an acre. This year the network was charged with a
Snook-Roentgen set, which consisted of an inverted rotary converter
supplying a 160-volt current to a 1-kilowatt 100,000-volt transformer.
A mechanical rectifier was used on the high-tension side to obtain a
pose charge on the network, the other terminal of the trans-

ormer being grounded. Even with this set it was not possible to
charge the network much above 50,000 volts. The treatment was
given daily from 3 to 7 p. m., except Sundays and during bad weather.

At harvest the weights shown in Table 9 were recorded.

62149°26—__2

10 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

TABLE 9.—Yields of winter wheat on plats following electrocultural treatment (posi-
tive charge), section B, Arlington Experiment Farm, in 1912

Yields (pounds) Ratio of treated to control
Plat - phe Te
Shock Grain Straw Shock Grain Straw
“ier 21) is Oe i ae eS 2 eee. oe © 3, 465 L, 154 2, 311 \ 1.05 1. 04 1.06

RG OTLGTD Bete ete: ee ea 3, 300 1, 114 2, 186 |

Experiments in 1915.—In the fall of 1912 the same plat in section B
was again sown to wheat. The 7-foot network of the previous year
was replaced by a permanent one 16 feet high, with cross wires 10
yards apart. The new network was erected over the northern half
of the plat instead of the eastern half as in preceding years. The
network was charged positively with the Lodge-Newman apparatus,
and the treatment was given daily from 4 p. m. to 8 a. m.

The treated and control portions each had an area of three-fourths
of anacre. At harvest the weights shown in Table 10 were recorded.

After the wheat was cut, cowpeas were sown on the B plat on
July 29, 1913.

The static machine was connected to the network (16 feet high),
giving about 40 to 50 kilovolts. The machine (positive charge) was °
run four hours a day from 3 to 7 p. m. for 32 days. On account of
the dateness of the season, the cowpeas were cut for hay. After being
stacked and cured, the crop was weighed in the field by means of a
tripod and spring balance, showing the following yields: Treated por-
tion, 1,807 pounds; control portion, 1,847 pounds; ratio of treated to
control, 0.98.

TaBLeE 10.—Yields of winter wheat on plats following electrocultural treatment (posi-
tive charge), section B, Arlington Experiment Farm, in 1913

Yields (pounds) pa Ne cy to
Plat

Shock | Grain Shock Grain

Mirescietier we oer Sere) a ee Oe Ss eee on eee | 3, 254

808
Control 782 \ 1. 04 1. 03

Experiments in 1914.—Corn was planted in the B plat on May 24,
1914, and the network (16 feet high) was connected directly to one
wire of a 6,600-volt 3-phase 25-cycle alternating-current power line
running past the farm. The voltage was on continuously day and
night for 110 days, when the corn was cut and the total weights
recorded in the field. It was then shocked and given time to dry.
Husking was done in the field on October 9, 1914, and the grain and
fodder brought to a platform balance in the barn and weighed. The

superintendent of the farm expressed the opinion that the treated

plat had had some advantage over the check plat as regards soil-
moisture conditions. The yields shown in Table 11 were recorded.

ELECTROCULTURE ti.

Taste 11.—Yields of corn on plats following electrocultural treatment (alternating
charge), section B, Arlington Experiment Farm, in 1914

Yields (pounds) Ratio of treated to control
Plat
Green Dry Grain Green Dry Grain
shocks shocks | (on cob) | shocks shocks | (on cob)
[NG29 [f.0 hep Uh a Ee cae ee Spe ep eee Sie aa 16, 031. 5 4, 060 2, 892
“04, 00 ped a ana ee a 13,775.5.| 3,952| 2,260 \ 1. 16 1,03 12

Ezxpervments in 1915.—The corn was followed by rye which was
sown in section B on October 22, 1914. The 6,600-volt treatment
alternating charge was started November 5 and maintained continu-
ously till June 24, 1915. This year at time of harvest each plat
(treated and control) was divided into eastern and western halves,
and each section was weighed separately to show any inequalities in
soil conditions.

The yields recorded at harvest showed a lack of uniformity in the
plats, but gave no evidence of a sensible increase in yield due to the
electrical treatment. The results are shown in Table 12.

TaBLE 12.—Yields of rye on plats following electrocultural treatment (alternating
charge), section B, Arlington Experiment Farm, in 1915

Yields (pounds) Ratio of treated to

control
Plat hear bees Sti ats ba ON
Shock Grain Shock Grain
a tee eet Pose 565
IHGA G | oe ae, Ss mr a es a gga ia ea a ;
anneal) Nravivy cbt Gai boc 1, 350 525 \ L183 1,08
Western half: :
WIT (EG}PE plas Jeol S02 9 ek BO | hen ee ee he i oat ee ee 1, 304 481 93 93
ROSIER oe oe ek SS coe 8 I St Ss et US See? Se eine 1, 408 515 %
Oka a5
OHO ee a yee a Teer pee BRN Pad Pe a 2, 836 1, 046
Control..____. MUR ste es 2, 758 1, 040 \ 1.03 1.01

Experiments vn 1916.—In order to measure the relative yielding
power of the two plats (treated and control) under normal condi-
tions wheat was again sown in the fall of 1915 and allowed to mature
the following summer without electrical treatment of either plat.
Table 13 shows the figures recorded at harvest, the north plat being
the treated plat of the three preceding years.

‘TABLE 13.—Yields of winter wheat on plats without electrocultural treatments,
section B, Arlington Experiment Farm, in 1916

Ratio of north to

| Yields (pounds) south plats

Plat pe Bis ed BEE ee oP TY
Shock Grain Shock Grain
Heskgor halt: i
SUL TE i) LOVEE 2 2a as te RR ea i a eS i OA OO 1, 568 456. 5
Remrieeri ig a tiled 213... le 1.660 | 542.0 \ 0.95 0. 84
eriern halt:
emenraes ate ee ek ES TT PD ETL. Se Ais 1, 448 403. 5
TCE SNE Rigel Ga 1a aa 1.752| 467.0 \ 83 - 86
he att
GQiljdhel Gig Ree eee CPUs OES Ee POPs 2 We ee ee 3, 016 861.0
“oo _Giechael: Se agesasien Angi se aie aban ane arags 3/412 | 1,009.0 \ 88 85

12 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

SUMMARY OF EXPERIMENTS IN SECTION B

The 1916 results show about 15 per cent difference in the yield of
the plats when no electrical treatment was used, the control plat
giving the higher yield. During the preceding three years the yields
of the two plats were approximately equal. If the 1916 results are
accepted as indicating the relative productivity of the two plats
under normal conditions, the conclusion follows that during the pre-
ceding three years the electrocultural treatment increased the yield
15 per cent or more and that an alternating charge on the network
was equally as effective as a high positive charge. During the time
the network was connected to the alternating-current power line the
charge was changing sign 50 times per second, the maximum gradient
was about 1,500 volts per meter, and there was no appreciable ioniza-
tion at the network. The conditions were so different from those
prevailing when the network was charged to a steady high positive
potential that it seems highly improbable that the effect on the grow-
ing crop would be the same unless the effect is nil under both condi-
tions, the 1916 results not being representative. The latter conclu-
sion seems the more probable, and this is supported by the experi-
ments in section A which follow. |

EXPERIMENTS IN SECTION A

A plat in section A of the same dimensions as the one in B was also
used for electrocultural tests. The north half of this plat was
equipped with a 16-foot network similar to the B network except that
it had twice as many cross wires (5 yards apart). The two networks
were connected electrically, so that both received the same charge.

Experiments in 1914.—Soybeans were planted in section A in June,
1914, and subjected to a 6,600-volt 25-cycle treatment (alternating
charge) continuously from July 15 to October 19, when the crop was
harvested. The total weight of the crop from each plat was deter-
mined just after cutting, again after drying in the field, and finally
after threshing. The weights recorded are shown in Table 14.

TaBLE 14.—Yields of soybeans on plats following electrocultural treatments (alter-
nating charge), section A, Arlington Experiment Farm, in 1914

Yields (pounds) Ratio of treated to control
Plat
After After Beans After After Beans
cutting | drying only cutting | drying only
SURO 6 Ree ee lee ee ee ce 4, 093 2, 776 811.3
Gone. cI SS Sie SATS 4242} 2446 | 782.5 \ 0.97 1.13 1. 04

Experiments in 1915.—After the plat had been plowed and put in
good shape, rye was seeded on October 22, 1914, and the 6,600-volt
treatment (alternating charge) was started November 5 and main-
tained continuously until harvest. The field was divided into four
equal parts when the rye was cut, to get some idea of the soil variation
in the eastern and western halves of the plats. At harvest time the
crop under the network showed a much better growth than the con-
trol plat, but this was probably owing to soil conditions rather than
to the electrical treatment, as indicated by the comparative test the
following year. The yields obtained are shown in Table 15,

ELECTROCULTURE 13

TaBLE 15.—Yields of rye on plats following electrocultural treatments (alternating
charge), section A, Arlington Experiment Farm, in 1915

Yields (pounds) Ratio of treated

to control
Plat a5 bh ie a ee eee eee
Shock Grain Shock Grain
esters pat oe be
POT G22 22 2s ee ees Pee Se nee ee eee 115 6
Ree ME Mists FOr ate 868 363 \ 1. 46 1. 29
Dae Pale : a
CEES ED Ghee: Suet Bee oe 2 pei Sa a 1, 392 512
ptmeieiiitoo, gure irsiec nag Cie es 7 | 890 337 \ 1. 56 1.52
ec: ed 662 9
PREV ECG ap I eh ee Se ye san 2, 81
my ee leet yo 5 | 1,758 700 \ 1.51 1. 40
| |

_ Experiments in 1916.—Rye was again sown in section A in the
fall of 1915 and allowed to mature without electric treatment. This
crop was cut in June, 1916, giving the yields shown in Table 16, the
north plat being the plat treated during the two preceding years.

TABLE 16.—Yields of rye on plats-without electrocultural treatments, section A,
Arlington Experiment Farm, in 1916

Yields (pounds) | =#tlojof parks
Plat as ee eS Ee a
Shock Grain Shock Grain
Eastern half: | :
ee nee ee gE | aes | doa |} 288). <6
Western half k E
priwemem arn go to] ane. Lot]. 20
Total: =
geese ua se res or 2558 "sono |p bat} 148

SUMMARY OF EXPERIMENTS IN SECTION A

A comparison of the yields obtained in the field trials in section
A gives no evidence of an increased yield accompanying the use of
an alternating charge on the network.

ELECTROCULTURAL EXPERIMENTS IN THE PLANT HOUSE
TRANSPIRATION

The effect of a very high potential gradient on the transpiration
rate was investigated in plant-house experiments in Washington in
1913. Large galvanized-iron buckets were filled with moist. soil
and fitted with special covers to prevent evaporation from the soil.
Six rooted geranium cuttings were planted in each pot through
holes in the cover, the opening around the stem of the plant being
sealed with wax.

The initial weights were taken on February 15, 1913, and the
plants were allowed to grow until February 20 without treatment,
to determine the relative transpiration of two sets of six pots each.
One set was then placed under an insulated frame covered with
galvanized-wire screen of 14-inch mesh, while the control set was
protected from the discharge by being placed inside a Faraday

| 14 |. BULLETIN 13879, U. S. DEPARTMENT OF AGRICULTURE

|
|
eage of 14-inch mesh. ‘The frame was connected to the positive
i pole of the static machine, the other pole being grounded. The
| rame was charged four hours a day, from 3 to 7 p. m., from February
21 to March 24. The plants were again allowed to grow without
| treatment from March 25 to April 7. During each period weigh-
ings were made to determine the loss due to transpiration, and
(i water was added when necessary to maintain approximately the
initial moisture content of the #83
Table 17 shows the rate of transpiration for each pot during the
three periods and the ratio of the treated to the control set. It
will be noted that during the period of treatment no sensible change
occurred in the transpiration ratio.

TaBLeE 17.—Transpiration rate of geranium plants in pots under electrocultural
treatment in the plant house at Washington, D. C., in 1913

| Transpiration rate per hour (grams)

{
| : No treatment Treatment period No treatment
iH Pot designation
al | .
| | Feb. 15|Feb. 17| Feb. 20| P¢P- 25) Mar. 1| Mar. 5 | Mar. 13| Mar-24) apy. 4
i ) to 17 to 20 to 25 Anna to 5 to 13 to 24 Apr. 1 to7
ih} ce ren ees a eee a SS ee eS | Se
| Treated set:
110 fea 5 er A ee 3.6 5.1 5.1 2.9 8.3 8.0 8.8 LPC 10.5
GSH GU a otae 4 Pl gseckt one 3.0 4.7 6.1 3.4 8.4 8.0 9.5 8.2 10.9
: Lol il WY, 7 ake BE agers Me aes ee 2.9 5.3 4.8 2.9 8.1 7.6 9.0 a0 10.9
1 LOCO a 7 eg ca ee pa ae 2.6 4.7 4.4 2.9 i 7.4 9.4 8.9 11.4
{ POL He a ee 4.3 6.1 6. 4 3.3 9.7 7A!) dent 6.8 10.4
Male ysn PAD Se ee ek a | 5.0 4.9 3.2 7.9 6.8 8.7 8.6 11.4
RVlieseris 2) 4 7 SA 13 5.15 §. 11 3.10 8.35 7. 61 8.85 7. 98 10. 91
Control set: a
Gad ooo sacs be ek 3.1 4.2 4.3 2.8 7.0 6.5 8.4 9.1 1 Wie |
PON ee 30 5.7 6.0 3.7 8.6 8.0 8.6 3 10.7
ig aR 2 ale Fee ee 3.8 4.6 5. 2 3.4 8.1 7.6 8.9 8.2 10.6
} orate ee TE ZEEE 3.6 5.0 4.9 3:2 8.0 7.6 8.9 8.4 10.9
Peele 2 yt eet 4.3 ane 5.9 4.0 9.0 8.2 8.1 ek, 10.3
I OS wry Bs oe 3.6 Bye 5. 5 3.5 8.7 8.4 8.6 7.4 10. 6
he | 358] 508] 530] 343] 823} 7271| 858] 7.91] 10.70
th Ratio of treated to control - -- -89} 1.01 97 91 1.01 . 99 1. 03 1.01 1. 02

The total transpiration from the treated and control sets of potted

geranium plants for the three experimental periods is given in
Table 18.

|

|

| TaBLE 18.—Total transpiration of geranium plants in pots during the three experi-
| mental periods in the plant house at Washington, D. C., in 1913

|

Total transpiration (kilo-

grams)
sia ah No treat- tal at No treat-
ment F men

‘i period 4
Heb. 15 |Web, /21 to) Mee SE

Mar. 24 ‘n'y
SIpGRTICUNGU 2-2. Me Sec 2 tees «ae eg ee ag ee ee 3. 00 33. 42 20. 01
@onimalisebet i357 !).) Jes Re Oe, Se ee ee 3. 08 33. 42 19. 62
anoror breated'tO CONLLOI.._-...-.. 0 S82 2 ee ee eee 98 1. 00 1. 02

ELECTROCULTURE : 15

WATER REQUIREMENT ;
An investigation of the effect of a high potential gradient on the

water requirement of cowpeas was undertaken in a plant house

during the winter of 1918. [Eighteen large galvanized-iron®cans,
eri holding about 125 kilograms, were filled with well-mixed soil
and fitted with special covers to prevent evaporation. The cow-
peas were planted through holes in the covers, the openings being
sealed with wax. The pots were weighed at the beginning and at
the end of the experiment, and a record was kept of the water added
to each pot, from which the total quantity ao water transpired by
the plants in each pot could be determined. In brief, the procedure
was that followed by Briggs and Shantz (10, 11) in their water-
requirement Measurements.

These pots were divided into three sets of six each. Set No. 1

‘was placed on an insulated stand, with each pot connected to the
positive pole of a static machine; set No. 2 was grounded and placed

under a positively charged iron-wire screen suspended about 2 feet
above the plants; and set No.3 was used as a control and was protected
from the influence of the charged sets by a well-grounded wire screen.
The potential supplied by the static machine was above 50,000 volts.

As soon as the treatment started trouble was experienced with
the set beneath the charged network, soot and dust (large ions) being
deposited on the leaves and stems of the plants, and in fact all over
the house. A coating would collect on the leaves ovér night during
the course of a 16-hour treatment. The plants were washed several
times, but they did not thrive, owing in part at least to the great
reduction in photosynthesis resulting from the coating on the leaves.
This set was finally discarded.

The other two sets, however, grew well throughout the experi-
ment, although they were not so vigorous as plants grown out of
doors in the summer. ‘The positions of the pots in a given set were
Fav leer weekly, so as to provide average light conditions for
each pot.

"The plants were cut May 2, after 54 days of treatment for 16 hours
each day (from 4 p. m. to 8 a. m.), and they were dried at 100° C.
and weighed. The water requirement of the plants in each pot
was computed by dividing the total weight of water transpired
by the dry weight of the crop. The mean water requirement for
each set of six pots with its probable error was as follows: For the
treated set, 449+ 4; for the control set, 429+5. ‘A slightly higher
water requirement is thus shown for the treated set, the observed
increase being 4+1.2 per cent. If some of the water molecules
escaping through the stomata of the leaves carried a positive charge,
they would move away from the leaf more rapidly than under normal
conditions, owing to the strong electric field. This would be equiva-
lent to a virtual increase in the vapor pressure gradient near the
leaf and would tend to increase the evaporation rate. Although the
above suggestion is highly speculative, it would be of interest to
repeat the experiment, epaGne the electric charge during the
daylight hours when the transpiration rate is highest.

SUMMARY OF EXPERIMENTS AT ARLINGTON EXPERIMENT FARM

Electrocultural experiments extending over a period of eight years
havé been conducted at the Arlington Experiment Farm, Rosslyn,
Va., for the purpose of determining whether a highly charged network

16 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

will increase the yield of crops growing under it. The electrical
treatment was usually given during the early-morning and late-
afternoon hours. The general experimental procedure was similar
to thet employed in experiments in England in which the electrical
treatment is reported to have givep increased yields.

These experiments do not show any well-defined increase in yield
due to electrical treatment. There is an indication of a slight
increase in the yield of wheat when grown under a positively charged
network, but the observed increase is well within the experimental
error of field trials.

The results of these field experiments are summarized in Table 19.
The relative productivity of the plats when not subjected to the
electrical field was determined in order to provide additional informa-
tion in interpreting the results, a precaution which has not been
generally observed by other investigators. A discussion of the
yields from each section will be found in the text embodying the
description of the experiments.

TaBLE 19.—Summary of the results of the electrocultural experiments in sections A,
B, and E, Arlington Experiment Farm, in stated years

[The treated and control plats in sections A and B were each three-fourths of an acre in area; those in section
half an acre each, separated by an interval of 350 feet. Abbreviations and symbols —Column 2: C=Cow-
peas (crop cut fer hay); R= Winter rye; S=Soybeans; W=Winter wheat. Column 3: Numbers refer
to preceding tables. Column 4: A=25-cycle alternating current; N=No treatment; —=Negative
direct current; += Positive direct current. Column 12: *=Yield of plats treated in previous years]

Ratio of
Network treatment Yields (pounds) pine
control
lDeseri | |
: DP’ Time of |
beg aia oe pestment Dry shock Grain
ours
Section and date | Crop work |
| |
: ites §
o oS 3 ~~
é 2£)2 = 5 <
© is oo ? — Lo} — °
a eee: J ee — fe oe p P 2 BE taihg
7 ae ed My = s | > |S
a S Ce Nae. We a ° u iS RK] &
1 | 'o) > mM] om | Ay = G 1) & S Ne;
1 ; 2 ek Be) BAe et ie 8 11 12 13 | 14! 15
Section A: |
Cit ee be Bice d wee 14} A | 6,600] 16) 5/...___|-._- 2,776 |2,446 | 811.3] 782. 5/1. 13/1. 04
Op a7 2s AU ee LP od ee 6, 600) 16 ‘7 ee lzce2 12, OBZ, aly toe 981 700 }1. 51/1. 40
ADAG cen | 5 at oe BP IG(AN) ee 16 17} isin # Bethe 2,700 (2,558 |*1,147.5) 803 /|1. 44/1. 43
Section B:
eae i} See Wins: 9} + | 45,000] 7, 1/116 |__-_'3,465 |3,300 | 1,154 [1,114 |1. 05/1. 04
40, 000
NOTS 5s . e rere i, eS 10) + | to 16] 10)216 |____13,254 [3,139 808 782 |1. 04}1. 03
50, 000
[OLS 22 Sisters Ca SET _.-_| + | 45,000} 16) 10) 24 JOS SOT? TF847 oie ere debe es . 98)_-_-
GAS oS 2 ee Corn___ bh] AS |e oe ee 1a] ei | a a ee 6,952 6, 212 2,892 |2,260 {1. 12/1. 28
NOTS 22. ee Ay ee 12) A eee ees 14 (eT 1) aa a a 2,836 |2,758 | 1,046 |1,040 /1. 03/1. 01
AOLG 22. =e Ske Whe secs 13) ING hse ee pe es 3,016 3,412 *861 |1,009 | . 88) .85
Section E:
TOTS A323 3h ONS Roe fe Pin Mp Pe eae) ieee | (a) op oe) ee 2438 yD hOO ee tene we foes eee 4 OS isa 2
30, 000,
1G 14 eee Wit 2) + to 16} 5) 24 | 336/2,332 |2, 281 644.8] 656. 5/1. 02) .97
60, 000
30, 000
Lil eas ae W.tec oe 3} + to 16} 2| 32614) 345/1, 548 1, 362 624.5) 604. 5/1. 14/1. 03
60, 000
JOTG Re Eyes \ Psa eee 4! — | 45,000} 16 2) 1 16 800}2, 528 |2, 444 672 754 {1.03} .89
pute eee Wirth Sh MINF WE 22% Ree ae ok As ee 3, 190. 5|3, 064. 5) 1, 137. 5/1, 198. 5}1. 04) . 95
POISE ace VY ae ee 6| + | 30,000) 16) 1/116 | 736/2,820 |2,639 (|*1,050 {1,025 1. 07|1. 02
1From 4 p. m. to 8 a. m. 3 From 4 to 7 a. m. and from 5 to 8.30 p. m. be

? From 3 to7 p. m. 4 Plats separated by grounded wire screen.

ELECTROCULTURE 17

_ Plant-house experiments were also made on the effect of an electric
charge on the transpiration rate and the water requirement of plants.
The effect observed was well within the errors of experiment.

The use of electrocultural methods in their present state of develop-
ment as a practical means of increasing the yield of cropsin this country
is not recommended.

REVIEW OF OTHER INVESTIGATIONS IN ELECTROCULTURE

Electrocultural experiments may be divided into two main classes:
(1) Those in which the soil is the medium of conduction and (2)
those in which the air is the medium of conduction. Experiments of
the first class cover the use of soil currents resulting (1) from an
externally applied electromotive force, (2) from the galvanic action
of the soil moisture on zine and copper plates buried in the ground,
and (3) from the use of metallic uprights designed to collect and
carry atmospheric electricity to the soil. Experiments of the second
class are those in which the normal air-earth current is increased by
means of a highly charged network over the plants or decreased by
inclosing the plants in a grounded cage made of metal screen.

EXPERIMENTS WITH SOIL CURRENTS

Among the first experiments with soil currents on a large scale
were those by Ross, prior to 1844, (44) in New York. He buried a
copper plate 5 feet by 14 inches perpendicularly in the earth with
the 5-foot edge horizontal, and at a distance of 200 feet a zinc plate
of the same dimensions was similarly buried. The two plates were
connected above the ground, forming a galvanic cell. Potatoes were
drilled in rows between the plates and also in a similar plat without
plates. At the end of the experiment some of the potatoes from both
plats were measured, those from the treated plat averaging 214
inches in diameter, while those from the control averaged only half
an inch. The total weights at harvest are not given, and conclusive
assurance that the two areas were of equal fertility at the outset is
lacking. The supposed beneficial effect 1s rendered doubtful through
the subsequent discontinuance of so simple a treatment.

About this time Solly (46) conducted in England 70 small tests
similar in principle to those of Ross, the plates being 4 by 5 inches
and spaced only 6 inches apart. Grains, vegetables, and flowers
were planted between the electrodes. On comparing the appearance
of the treated and untreated plants a beneficial effect was recorded
in 19 cases, a harmful effect in 16 cases, and no effect in 35 cases.
Solly papi sed that electricity has practically no effect on plant

rowth.

F Fitchner (76) has recorded large increases from treatment with
galvanic currents. From his figures alone the experiments would
indicate increases of 16 to 127 per cent due to treatment. The
statement was made, however, that the treated plats were provided
with drains but that the control plats were not. Such conditions do
not constitute good Ee idental practice and leave the results open
to question. This same objection holds for accompanying experi-
ments on the decomposing action of the galvanic current on soil.

62149°—26——_3

18 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

In 1881, F. Elfving (75) undertook an interesting series of experi-
ments with different seedlings growing in culture solutions through
which he passed battery currents of different strengths. After
germination the seedlings were mounted on corks which were floated
in the solution between electrodes 6 by 4 centimeters in size. He
found that in nearly every case the root would turn and grow in a
direction against that of the electric current. Plates of carbon,
zinc, and platinum were used, and all gave the same effect. Elfving
attributes this phenomenon of orientation to the slowing up of the
growth on the side of the root toward the positive pole. This same
phenomenon was noticed by Plowman (40, 41) in 1902-03.

Holdefleiss (235) in 1884 selected several rows of sugar beets in a
field which showed a good stand and uniform conditions. In this
field copper plates 50 centimeters square were sunk perpendicularly
in the ground 50 centimeters deep, so that the plates included two
rows of beets. At the other end of the rows, 56 meters distant,
other plates were sunk, and between the two a 14-cell Meidinger
battery was connected. This same arrangement was used on a potato
field. Further experiments were conducted with copper and zinc
plates 33 meters apart connected by a solid copper wire. The report
of the experiments stated, in substance:

(1) That an electric current was present on all treated plats throughout the
season, its presence being determined by a sensitive electrometer; (2) that the
rows of beets and potatoes between plates which were connected to the battery
showed no difference in growth at any stage of their development; (3) that the
beets and potatoes in rows between the zinc-copper combinations assumed a
somewhat fresher and stronger appearance about 10 days after the beginning of

the experiment, and the harvest showed an increased yield ranging from 15 to
24 per cent.

It should be remembered, however, that in experiments with soil
currents the path of the current is not wholly by the most direct
route from one electrode to the other, but that the lines of flow
spread out through the soil in a way similar to the spreading of the
lines of force between the poles of a bar magnet.

Experiments conducted by Wollny (48) included five plats 4 by 1
meter each in size separated by a path 1.2 meters wide and by boards
sunk 25 centimeters in the ground. On plats 1 to 3 a zinc plate
was sunk at both of the narrow sides, and these were connected as
follows: Plat 1, induction coil operated by three Meidinger elements;
plat 2, a battery of six Meidinger elements; plat 3, a battery of
three Meidinger elements. On plat 4 a zine plate was sunk on one
end and a copper plate at the other, the two being connected above
ground by a copper wire. Plat 5 constituted a check or control plat.
Each plat was divided into four equal parts 1 square meter each
in area and seeded. Numbers of plants up on different dates showed
practically no effect for any of the different treatments. The yields
recorded at harvest time, based on an equal number of plants per
square meter, are shown in Table 20.

ee

ELECTROCULTURE 19

TasLe 20.—Yields of rye, rape, bean, and potato plants after electrocultural treat-
ments in 1883, according to Wollny

Yields per square meter (grams)
Plat Treatment
Rye, Rape, Beans, | Potatoes,
42 plants | 42 plants | 42 plants| 5 plants

(Gy eu re NmiGuicitpness= = serene Fee 182. 0 | 114.8 51725 372.1
iV 7 ee tee lGicells £9. s282" 7 ehgt PLE) ae) ek Ppa tie 219. 8 | 94. 5 514. 5 310. 5
int fee) et TASC he te Ns Bie Si ee RS ae eee 197.8 | 103. 0 420. 0 315.3
ly Rae ee Se Gi 0 Ate ee pe 8 ee te ee es CR ee 201. 6 114. 7 600. 0 397.8
1 ee ne ee ee ee fp Gombe) te. a 23 iter Ho) Pot eee 228. 72} 118.7 631. 0 377. 6

These records show that in nearly all cases the control plat gave
the best yields, but further experiments were conducted in 1886 and
1887. The ground was well worked over, and four plats 16 by 2
meters were selected, separated from each other by paths 1.2 meters
wide and bordered by wooden lath walls. Each plat was divided
into eight smaller plats 2 meters square and all were given equal
applications of manure. On the small ends of the four large plats
zinc plates 2 meters by 30 centimeters in area were sunk perpen-
dicularly and connected above ground through an induction coil
operated by 4 or 5 cells for plat 1 and through a 4 or 5 cell battery
for plat 2. Plat 3 served as a control, and plat 4 had a copper plate
at one end directly connected by a copper wire with a zinc plate at
the other end. Diagonally lying plats were planted with the same
crops, the grains being drilled to give a uniform planting... The
presence of a current on all treated plats was noted by the use of a
galvanometer. Throughout the season there was no_ perceptible
difference in growth between treated and control plats during either
year. The comparative-yield weights are shown in Table 21.

TABLE 21.—Yields of vegetable crops after electrocultural treatments in 1886 and
1887, according to Wollny

| Yields per plat 2 meters square (grams)

Plat Treatment | | | | | |
yas owe | Pota- Tur-
Rye | Rape Peas | Beans | Corn | toes Beets _ nips
: a Feels, Sry rise aT raeee
In 1886:
INO, Tasos Induction____- 113.3 | 339.0 1,420.0 | 2,040.0 a ae 6,400 | 23,400 | 22, 250
WOOL tt Ste) ees ee 108. 6 300. 5 1, 570. 0 2 ALO 0) iin Fe tee 4,650 | 24, 420 18, 080
Doe ete Controls. - 107.8 | 405.8 PPA SOR OC 2, eae sen ae 2 6, 620 | 28,100 | 21,520
: ae NESS Gurmm 2) | 100.9} 418.0} 1,490.0] 2,190.0 |______-- 6, 670 | 29,400 | 20,800
n 7
Ons ae Induction_____ 933.0 | 775.0 548. 0 696.5 |1,962.8 | 8,350 | 19, 640 17, 850
Wo. Ziisct epliss-slistee 879.0 | 755.0 588. 0 607.0 }1, 923.6 } 8,190 | 17, 650 18, 270
No 5 pe eee Oontrols= 24-2! 948. 4 773.0 592. 0 584. 2 |1,913.6 | 8,410 | 18, 900 18, 460
INO= 428-4 STEEN S22 2 12. 838.5 | 761.6 571.0 465.0 |2, 072.9 | 8,920 | 16, 320 19, 660
|

From these experiments Wollny concluded that an electrical cur-
rent conducted through soil in which plants were growing had in
general no influence or possibly a harmful effect on the productive-
ness of the plants.

Leicester (29, 30) used boxes of soil 2144 by 3 feet in area, with
copper and zinc plates connected above ground. Control boxes
without plates were included. After several trials with different

i |
i
|
Hi

20 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

kinds of seeds, it was found that in every case the seeds grew much
quicker in the boxes containing the plate. Hemp seed was fully an
inch above the surface before controls showed any plants. The
observation was made also that plants in the zones nearest the plates
were the first to come up. Watering with dilute acetic acid was
found to cause quicker growth for treated plants—possibly because
of increased current resulting from the acid-metal reaction. Upon
repeating these experiments, Leicester decided that the only action
of the current was to stimulate the plant until the initial store of
food was used up. No data were recorded in either of his reports.

Berthelot (3) conducted some tests with soil currents to determine
whether electricity aided in the fixation of nitrogen by plants. Suit-
able control plats were provided. He reported that the treated
plants grew much more rapidly, being nearly twice the weight of
the control plants at the end of four to six weeks. Although not
complete or definite, the experiments were abandoned for various
reasons.

Kinney (27) made an extensive series of experiments to determine
the influence of electrical currents on germination. Seeds were sub-
jected to different current strengths for different periods of time and
then put in suitable germination apparatus and the subsequent
growth noted. An intermittent treatment of 30 seconds per hour

was given in some Cases, arranged by clock contacts. Two different.

arrangements were used for the treatments. In one a glass cylinder
containing the seeds was equipped at each end with electrodes.
These were pressed against the seeds through which the current was
thus directly passed. In the other, the seeds were placed in wet
sand held between perforated metal disks, which were used for the
electrodes. The entire layer was held in a glass funnel in which the
growth of the radicle could be measured without removal. Eight
sets of 25 seeds each were used in each test, one set being the control
and the other seven receiving different strengths of current. Experi-
ments with barley showed that the growth of treated seeds increased
as the current strength increased up to a certain optimum value,
above which the growth decreased with increase in current strength.
With white mustard, rape, and red clover the optimum treatment
for both roots and stems was identical.

Plowman (40, 41) has recorded the results of experiments con-
ducted at the Harvard Botanical Gardens on the influence of soil-
conducted currents on plant life. Platinum or carbon electrodes
were used, with potentials ranging from 5 to 500 volts. The regu-
lation of temperature was a serious difficulty—a fact mentioned for
the first time in connection with such experiments and one that may
have been ignored in earlier reports. Fiennes found that seeds
near the anode were always killed by a current of 0.003 ampere or
more if continued for 20 hours. Seeds at the cathode were little
affected by currents less than 0.08 ampere.
~ Gerlach and Erlwein (19, 20), at Bromberg, investigated the
effect of weak soil currents on germination and growth. The field
was made up of seven plats of 200 square meters each. Current
was taken from a car line and led to the three treated plats, which
were provided with iron plates 20 meters long by 30 centimeters
wide and 2 millimeters thick sunk into the soil at both ends. Each
of the seven plats was seeded half with barley and half with potatoes.

ELECTROCULTURE 21

The treatment continued 24 hours a day for 86 days for barley and
139 days for potatoes, beginning in April. Both barley and potatoes
showed excellent growth, but no differences between the treated and
control plats were discernible at any time. Other experiments
were conducted with plants grown in boxes provided with copper
and zinc plates connected overhead by wires. Trials with rye,
wheat, secs lupine gave no difference between treated and untreated
crops.

omberger (24) reported that the passage of high-frequency
currents Binameh the soil was beneficial to plant growth. His
experiments were conducted on a small scale, using flowerpots with
only a few plants, the treatment consisting of three applications
daily until the temperature of the soil reached 35° C., when the
current was cut off. The leaves and stems of the treated plants
showed more chlorophyll than the controls. A photograph shows
one pot each of treated and control plants, the treated plants being
about five times as high as the others. In order to determine
whether the heating was the main cause of increased growth another
pot was subjected to test currents for five minutes daily. These
plants were about four times the height of the controls when photo-
graphed. From these comparisons Homberger concluded that the
oscillating field and not the temperature was the main cause of the
stimulation, and he believed his results to be due to chemical changes
taking place under the influence of the oscillating electromagnetic
field, analogous to the catalytic action of light.

In 1907 (17) and 1909 (18) Gassner reported upon experiments
with charged soil which indicated a general unfavorable action upon

lant growth.

Ké6vessi (28) obtained unfavorable results in researches involving
some 1,100 experiments.

Considerable publicity has been given to an apparatus called a
““veomagnetifier,’ a sort of lightning rod designed to gather in
atmospheric electrical energy and supply it to the crops. Among
those who have reported favorable results through the use of such
apparatus are Maccagno (35), Basty (2), and Paulin (39).

At the present time methods of electroculture employing soil-
conducted currents have few proponents.

EXPERIMENTS WITH MODIFIED POTENTIAL GRADIENTS

Grandeau (21), in 1878, reported studies on the effect of the
electrical condition of the atmosphere upon the growth of vegetation
He grew plants in a Faraday cage consisting of four iron rods 1.
centimeter in diameter by 1.5 meters high, holding fine iron wires
forming 15 by 10 centimeter meshes. The cage was grounded in
order to destroy the normal electrical field. Experiments were
made with tobacco, corn, and wheat. The plants under the cage
were reported weak and slender. Six stalks of wheat grown in
free air weighed 6.57 grams, as compared with 4.95 grams for six
stalks grown under the cage.

Grandeau was led by these experiments to the belief that high
trees act as a grounded network, in that they shield the vegetation
beneath their foliage from the action of the normal electrical field,
thereby causing a decreased rate of growth. With a sensitive
Thompson electrometer, he compared the strength of the field in the

92 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

open with that under vegetation. The results indicated that. under
trees and shrubs the potential gradient was greatly reduced. The
experiments of Grandeau were confirmed by Miaxeart (36).

As opposed to the conclusion of Grandeau, the modern greenhouse
of steel construction constitutes in itself an approximation to a
Faraday cage about the plants growing within it, and yet the develop-
ment of the plants is surely not seriously impaired in consequence.
Likewise, Briggs and Shantz (10, 11), in their investigation of the
water requirements of plants, carried hundreds of pots of plants to
full maturity under a grounded metal framework, covered above and
on the sides with metal screen of %-inch mesh, which must have
annulled the normal electrostatic field; yet the plants grown within
the inclosure were almost without exception superior in development
and luxuriance of foilage to those grown in similar pots outside.

Lemstrém (32) conducted in Finland a long series of experiments
to determine, if possible, the influence of static electricity on plant
erowth. The presence of strong electric charges in the atmosphere
of northern regions, as indicated by the northern lights, linked with
the astonishing development of vegetation in such regions, led him
to regard atmospheric electricity as an important factor in plant
growth. Garden vegetables, fruits, and small grains were subjected
to several different treatments in these investigations both in green-
houses and in open fields. LLemstrém summarized the results of his
experiments as follows:

(1) The real increase due to electrical treatment has not yet been exactly
determined for the different plants, but we are approaching its smallest value by
fixing it at 45 per cent. :

(2) The better and more scientifically a field is cultivated and manured, the
greater is the increase percentage. On poor soil it is so small as to be scarcely
perceptible.

(3) Some vegetables can not endure the electric treatment if they are not
watered, but then they will give very high percentage increases. Among these
are peas, carrots, and cabbage.

(4) Electric treatment when accompanied by hot sunshine is damaging to
most vegetables, probably to all; wherefore if favorable results are to be arrived
at the treatment must be interrupted in the middle of hot and sunny days.

Experiments similar to those conducted in Finland were conducted
in England, Germany, and Sweden with like results. A detailed
description of all of these experiments may be found in “ Electricity
in Agriculture and Horticulture,”” by Lemstrém (32).

Priestley (42, 45) reported on the experiments of Newman (37)
at Golden Valley Nurseries at Bitton. A small Wimshurst machine
was used, one terminal of which was grounded and the other connected
to wires suspended over outside plats and also to wires in seven glass-
houses. The wires were hung 16 inches above the tops of the plants
and were provided with discharge points hung at short intervals.
The machine was operated 9.3 hours a day for 108 days between
March 27 and July 26, the first half of the period in daytime and the
latter half at night. Control plats were provided in all cases similar
to the treated plats except without wires. The results recorded
are given in Table 22.

ee

ELECTROCULTURE 23

TaBLE 22.—Results of electrochemical treatment of garden crops at Bitton, as
reported by Newman

Crop mei Notes
Per cent

SUR DerS HINCLCASE eee nes> yt AEM se TER Ss bee 17 Less subject to bacterial disease.
Strawberries:

PVeaArplants wncrease. 2. 2. F fale S28 eee 36

t-year plants; amcreasessoi =. 22-4225 yee we tas 222 2 80 More runners produced.
Be nGncdaentiss \GCreASC. x2 eS ees oe ee cee ene 15 5 days earlier.
‘CMW ies 23s io LS eas ee eee ke ee oe reas
Welenyalnenenserer ».2 eee 8S ee es fe 10 days earlier.
pRamnides: GTOrcitenrelice) a. 2 22 9852 ee eee Me Le oe eel |

During the same year an installation was working at Gloucester
with ais, voltage and wires 5 feet from the ground. The following
results with treated plants were reported: Beets, 33 per cent increase
and higher total sugar content; carrots, 50 per cent increase; turnips
showed an increase, but the percentage was not recorded owing to
slugs.

ie 1906 Newman (37) and Lodge (33), at Evesham, began some
electroculture experiments using about 40 acres, 20 of which were
electrified with a network 15 feet above ground. The Lodge ap-
paratus was used, 22 poles carrying the wire over the area, with small
wires 12 yards apart. These experiments were continued several
years. The results are summarized in Table 23.

TABLE 23.—Results of electrochemical treatment of crops.at Evesham in stated
years, as reported by Newman

Electri-
Year and crop fied Notes
; crops
1906:
Wheat (electrified area 12 acres)— Per cent
BAG os 7% ae eu ene one ees igen
: : ound it produced a Detter baking flour. The
Eagle pee ee aH somewhat poor yield from the control plat was
mutes: Ean TRON a 3 probably due to deficiency in lime, afterwards
rectified.
1907:
Wheat (electrified area 11 acres), in- { 29
crease. 18 Estimated by cartloads.
Strawberries, increase_.._......-.-.----- 25
1908:
Wheat (electrified area 7.68 acres), in- 24. 3
crease,
Strawberries, decrease._____.___________- 9 Dry season.
sDOUIALOGS LNGrEASer se + our kt ME Fe 30 By weight per plant (average).
Cucumibers; mcrease 2 soe 8.4 | By number (average).

Newman reported later (38) that during seven successive years
(1905 to 1911) wheat gave an average increase of 21 per cent in weight
of grain and an increase of straw which it was not possible to measure.

Potato variety experiments conducted at Dumfries, Scotland, by
Dudgeon in 1911 and 1912 (/4) gave the yields shown in Table 24.

94 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

TABLE 24.—Results of electrocultural treatment of potato varieties at Dumfries,
Scotland, by Dudgeon in 1911 and 1912

Yield (tons) | Yield (tons)
Variety ee ee Variety See
Treated | Control Treated | Control
mingleader: 2212 ees eee ye 8.05 5.85 || Golden Wonder___-_.___-_..-- 8. 74 8.12
WindsorC@asthie = Us ee 18 Re 95881 Grestt Scot 222 ee ee 11.79 10.31

In 1912 further experiments at Dumfries were carried on in another
field, exposed to wind from any quarter. Two corners of the 4
acres were treated, the others left as controls. No difference in

ield was recorded, and it is explained that probably all plats are to

e regarded as treated plats.

In 1915 Dudgeon conducted an experiment with oats. The crop
was grown on ground that had been used for similar experiments
on potatoes for three years. Two adjacent plats of 114% acres each
were separated by a well-grounded wire screen 3 feet higher than the
charged network. <A sensitive electrometer showed that the screen
reduced the leakage over the control plat but did not altogether
prevent it. The season was dry and the crop was not heavy. From
early stages the treated plat showed a marked superiority in com-
parison with the control, and did not suffer from the prevailing
drought to the same extent. The electrical discharge was applie
about five hours each day for 108 days. The weights (pounds)
recorded at harvest were as follows: Treated—grain, 1,309, straw
2,476; control—grain 1,008, straw 1,572. .

These figures indicate an increase of about 30 per cent in grain
and about 58 per cent in straw. Analyses of the grain from the two
plats showed practically no difference in quality.

Blackman and Jgrgensen (6) have also reported experiments by
Dudgeon at Dumfries, Scotland, with oats. In a 9-acre field 1 acre
was selected for treatment and two half-acre plats for controls.
The distance between the silicon-bronze wires of the network was 4.5
yards. Current of 3 amperes at 50 volts was supplied to the primary
circuit, giving a greater intensity of discharge than that obtained
in the experiments of the previous years. The discharge was started
just as soon as the crop appeared above ground, and within a month
a marked difference was noted. The treated plants had deeper color
and were higher than the control plants. Throughout the season the
treated crop was 5 to 10 inches higher than the control. Plants
around the network also showed the effect of the discharge. The
total application from April 14 to August 17, daytime only, was 848
hours. Heavy rains did a good deal of damage. The comparative
yields were as shown in Table 25.

TaBLE 25.—Results of electrochemical treatment of oats at Dumfries, Scotland, by
Dudgeon, as reported by Blackman and J¢rgensen

Yields (pounds)

Field ; _ Grain Straw

Quality 1| Quality 2! Bunches | Total | Per bunch

Montroll!(half-acre)= oc Sao. Ae ee ee 630 210 99 1, 218 VAR
APREAUCACACTC) .0 ~~. lek yee oe eee ees 1, 942 695 316 4, 924 . g
13.

= Gontroue (half acre) .~-2 5 apace Fhe eS 714 210 103 1, 401

ELECTROCULTURE 25

These results indicate a 49 per cent increase in grain and an 88 per
cent increase in straw for the electrical treatment.

The Liverpool City and Electrical Engineers reported on experi-
ments conducted near Liverpool, England, in 1917. Two plats in
newly plowed pasture land separated by about 375 feet were used,
an analysis indicating that the surface and subsoil were of the same
character. Various plant crops were grown, and in general the elec-
trified area gave substantial increases in yield over the control area.
A copy of this report is on file in the Office of Biophysical Investi-
gations, Bureau of Plant Industry.

Honcamp (25) has summarized the results of several previous in-
vestigations and pointed out serious objections to the methods used.

TaBLe 26.—Results of electrochemical treatments of oat crops at Mocheln, Germany,
* according to Gerlach and Erlwein

[

Relative yields Composition (per cent)
j i ;
Electrical and soil treatment i Grain Straw
Grain Straw f
eas | Nitrogen | cg Re Nitrogen
No electricity:
Fertilizer, wrpation “st 26. 60 34. 40 91.4 1. 94 77.4 0. 32
1) Gisht te beh A ee eee eee eee 28. 80 32. 20 92.4 vit) 76. 2 BPA
Fertilizer, no irrigation_______________- 20. 60 24. 40 87.9 2d 73.5 . 46
Giens sists) hae eee eee 20. 90 22. 10 89.9 2. 04 74. 3 . 38
No fertilizer, no irrigation____________- 19. 60 19. 40 90. 4 1. 85 78.8 ~ a2
LD Gt ee te ee eee 19. 60 17. 40 90. 1 1. 67 79.8 an
Direct current:
Positive, fertilizer, irrigation__________ 27. 80 36. 20 90. 4 1. 94 71.6 aL
Negative, fertilizer, irrigation_________ 27. 80 37. 20 91.7 1. 74 72.9 24
Positive, fertilizer, no irrigation_______| 21. 60 24. 40 90. 5 2.16 74.5 . 36
Negative, fertilizer, no irrigation______ 20. 50 22. 50 91.2 2. 07 73.7 . 30
Positive, no fertilizer, no irrigation____. 21. 00 23. 00 84.4 1. 88 76.6 - 28
Negative, no fertilizer, no irrigation ___| 17. 80 18. 20 90. 4 1.72 78.4 . 28
Alternating current:
Hertitizer irrigation. 52 ==. t= 26. 20 31. 80 91.7 1.81 78.4 . 28
LSS = NS a eg ee ee 26. 00 32. 00 90. 6 1.78 77.9 pp’
Fertilizer, no irrigation_._______________ 19. 50 21. 50 91.3 2. 16 73. 2 33)
SG. SE eee eS ee eae 19. 90 21. 10 89.8 2.11 75.9 . 30
No fertilizer, no irrigation_____________ 18. 00 18. 00 91.1 1. 84 | 82.2 . 28
pene ss Se 18. 00 18. 00 91.4 1. 83 | 85. 0 . 26

SUMMARY OF RELATIVE YIELDS OF GRAIN AND STRAW

High-tension current

No elec-
Soil treatment tricity Direct
: Alter-
| nating
Positive | Negative
Grain:
IGMGrMIP Or NOMTTMPALIGN 2425 td ee 19. 60 21. 00 17. 80 18. 00
MeriiwereHo wri ion = 9 20. 75 21. 60 20. 50 19. 70
Mem Myer aIsripatlon ts 6 rood iii fey ee 27.70 27. 80 27. 80 26. 10
Straw:
PIOMeniAtzer HOMTEICALI ON: £22) | eo oe. Pas ost 18. 40 23. 00 18. 20 18. 00
LICETS LESTE a Dart oe | (0) 2 en 23. 25 24. 40 22. 50 21. 30
CERIN OR MET En iO Senet, Siti elo ili “o0/o Ce ie) AE 33. 30 36. 20 37. 20 |. 31. 90

On the Continent during this period many electrocultural experiments
were carried out, using networks charged to high potentials. Reports by
Héstermann (22), Gerlach and Erlwein (19, 20), Clausen (13), Breslauer
(9), and others indicate that no benefit may be expected from the use
of the network. The German experiments made use of an extensive

—

26 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

and variable complex of conditions, designed to include the study of
positive and negative potential in relation to fertilizers and irrigation
and the relation of these factors to the composition of grain and straw.
The results shown by Gerlach and Erlwein reporting experiments
with oat crops at Mocheln areselected as representative. (Table 26.)

It may be well worth while to consider Table 26 in some detail,
since it seems to represent a thoroughly impartial study of the
methods which have given success elsewhere.

The instances in which duplicate trials were run and the agree-
ments to be noted for these cases show rather conclusively that lack
of uniformity in soil-conditions was not a disturbing factor in these
experiments. The six plats giving notably higher yields are those
with fertilizer and irrigation. These are in good agreement and show
no appreciable advantage for the three types of electrical treatment
represented, the averages for relative yields only being as shown in
the summary of Table 26.

The plats in these experiments were about one-fourth acre each,
the control plats being separated from the electrified plats by about
325 feet. The potential of the direct-current network was about
30,000 volts, whereas that of the alternating current was about
20,000 volts. The statement of Lemstrém that the better the con-
dition of the field the more favorable the influence of the high-tension
discharge is not substantiated by these trials. In brief, the German
experiments give little evidence of any definite crop increase at-
tributable to the electrical treatment.

In 1913 Dorsey conducted greenhouse experiments in Ohio with

radishes and lettuce, using a high-frequency current. In a letter to

Doctor Briggs dated August 18, 1913, he reported the relative weights
of 10 plants selected at random from each area. These are shown in

Table 27.

TABLE 27.—Results of electrocultural treatments of greenhouse radishes and lettuce
in 1918, according to Dorsey

Relative weights (grams)
10 plants Radishes Lettuce

Treated | Control | Treated | Control

AiR = cote Mee. Ae. eed ties pe ee oe eae a 265. 7 180. 0 67.0 46.1
LOPE ID) DWy Cyn Are) 0 ph ee Oe OS Meat Re Boe fails tae 1 eS SE UA one eae 139. 5 79. 4 60. 7 41.8
Ley 0 Re oo hoy Ak Sa ae de ae ee RL ee ee «Skt eae Mae eee 120. 5 90/0 28 See ee
COTS same ees eS 8 ade 5 eee Bee we ee 9.3 5.6 6.3 4

Dorsey also conducted field trials with a high-frequency current.
The plants used were beets, lettuce, cabbage, beans, melons, cucum-
bers, and tobacco. They were planted in long rows, one-half of each
row being under the charged network. The treated plat covered
about half an acre. The network was 9 feet above ground with wires
15 feet apart and carried a voltage of about 50,000 at an estimated
frequency of about 30,000 cycles. The power was taken from a
744 kilowatt 220-volt transformer supplying 11,000 volts at 60
acycles and exciting an oscillating circuit containing the network as
capacity. Treatment was given daily, three hours in the forenoon

_

——

ELECTROCULTURE XT

and three hours in the afternoon. A generally favorable influence for
the discharge treatment was reported. Unfortunately total weights
- were not included. The results for the second year were generally
unfavorable for the discharge treatment, and Dorsey concluded that
erhaps slight differences in the slope of the two plats may have
a responsible for the favorable results of the first year.°
At the present time perhaps the best evidence of plant response to
electrical discharge is that obtained by Blackman (4, 4, 6, 7, 8)
of the electroculture committee of the British Ministry of Agricul-
ture and Fisheries. His experiments extend over a period of years
and comprise field trials, pot cultures, and laboratory tests, all of.
which he interprets as affording converging evidence for a favorable
growth response to the application of electricity. On account of the
practical possibilities associated with a treatment assuring increased
rowth it seems desirable to examine in some detail the data which
ave given rise to this assurance. ;
The field trials carried on in England by Blackman and his as-

sociates have given the results which are summarized in Table 28.

TABLE 28.—Results of electrocultural treatments of grain crops in England, as
reported in field experiments by Blackman

Yield per acre

' Se ake eenviow 1 (ushels) Ratio of
Crop and year Location ont treated to
(hours) control
Treated | Control Treated | Control
ELE 2 ie VaR $e fl EoEe OR ef yo WE 2 ee Be ee Ee ee ie eee | ee A
Oat:
149) Rye Fass creas Wingludeness: be° o2V 15 1.5 557 Det 16.0 1. 29
|G | (ee ee ae 70 Ko) a et a Dee Sg 1.0 1.0 848 62.8 42.0 1.49
540 Wy (cen Bi a i CONS Ys 53 Ae eae er neat a eSB) se 8 1, 060 54.8 48.9 1.12
1 ee al go (ae MOVs set wake Dake .33 33 1, 060 42.2 44.9 . 93
EO (ee ese ae (Gl 0) 25 eae a hc .30 33 1, 060 36. 9 38. 1 - 96
1 ee ee ee GCP =e eee ee ary: , 06 704 15. 5 56. 1 1. 34
BGIB i fetapee sip Sted. OE se Se papery 3125 06 704 84.9 58. 4 1.45
AQIR. 2 arts S[shis3- GOs abt rest he wryie 575 06 704 80. 4 46.3 1.73
POLO s etiad be 8 2 GOS E Piotiveuls Zpet Bal il 11 710 36. 6 45. 2 . 80
1OIG Ses Sige (Cea > So ee ee ee lit a alie 710 45.1 43.8 1. 02
TOTO Rese ee eee Ciijereem entre heer Die Sit mili 710 53.3 28.9 1. 84
19S. = Harper Adams Agricul- . 50 ape 456 47.0 53. 6 . 87
tural College.
aK?) 9 alee a Pee Ma Cl Opeem >. ake 2 ae 2D 33 456 63. 8 48. 2 132
TO1Quaria a ae "i 40 p-a te 5 a oe ee 9 cm, hs poe eee! 456 50. 8 48.2 1.05
OLOE Beatie Gale tes OH aea ees Hee” Jae 250 33 456 60. 2 59. 6 Gt
1920 tas IN GlUIG eI te i). salit eebl 911 36. 2 44.8 . 80
TODO aie Se? eae ek GUO) ch md, I eb dha sit Silat 911 43.5 46. 1 . 94
AOD 0 fae edt Ie Cee sk oh Or Sate A 911 61.8 33. 0 1. 56
1920: fe22 24 Harper Adams Agricul- woe, OST Ie 793 50. 0 56. 0 . 89
tural College.
O20 325" eet i Fa (hi RES Mts eee eee oo. Pysara lik 793 §2.5 56. 0 93
Barley:
ROLZSS 282 2-2 Rothamsted 222 __ 422 . 0125 . 0125 1, 500 17.8 13. 1 1.35
2) fc Se an es S| GoeE Suga ta - 66 . 10 643 44.7 36. 4 1. 22
TS eee cee ee es (0 | OR yeni Nae AA arr decree . 66 .10 643 47.4 52. 7 . 89
MOISES pI PAL tre GOPves tlhe ore . 66 . 10 643 40. 4 36.3 Ld
Kt). DS ES ae ee GE se SN be Bivens . 50 . 50 786 31.7 29. 5 1. 07
i A UN a 0 a i oer (a) PRS OS Serna a bc . 50 . 60 786 33. 0 25; 17 1.31
Winter wheat:
Teaco te 9 (FPR heh < Bree SR te Ao Sees . 50 . 50 854 21.4 14.3 1.49
TODD Res ee ts LOE / Seva Pe BC Pe PSE . 50 50 854 22:3 17. 4 1. 28
LODO ee. Sa sly s S CEO hot Se BY aes on 20 25 727 18. 84 20. 4 . 92
g 49 2. U0 hs et Bc | al (6 (og hose ie SS «20 25 727 18. 35 18. 24 1. 006
Spring wheat:
vt 7 Ee ate eal ear 140 Wha gears ear aN a 50 ~oG 940 6 10. 0 . 76
ID eee Meise oF 0) 0 pueed BS ee eel Bee CE OG | DEES eras 500 940 \ 7.3 | 7.9 . 92
pe ean ae fot te ORE ate 2 aa . 50 . 33 940 | . Ne 638 1.15
Se RY eS 2) Beers eee Ee ONES OOo eee ee a Oo ee 1.14

5 Correspondence with the Office of Biophysical Investigations, Bureau of Plant Industry, September
? ,

|

98 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

These tabulated values are in many ways not subject to biometrical
analysis; they represent the results of experiments carried out with
varied complexes of soil, season, acreage, crop, and electrical treat-
ment. Nevertheless, in the absence of any datinite knowledge con-
cerning the conditions under which an electrical treatment may be
presumed to be most effective there is perhaps no better index than
a comparison.

Of 33 trials shown in Table 28, 21 indicate an increase for treated
areas, whereas 12 indicate a decrease. The treated areas return a
yield represented by the range 76 to 184 when the untreated areas
return a yield represented by 100 and give an average increase of
14 per cent. This increase is based upon yields reported for experi-
ments regardless of crop or seasonal normality, and Blackman esti-
mates the more reliable experiments as indicative of an average
increase in yield of about 22 per cent. In either case, such an in-
crease would seem sufficient to be of promise from an agricultural
standpoint. If an attempt is made to determine from these tabu-
lated values the conditions under which the increases were obtained,
serious difficulties are immediately encountered.

Unfortunately the normal productivity of the electrified and
control areas is in most Gases unknown, and a serious lack of soil
uniformity is evident from the yields of different portions of control
areas. Jor example, in the 1919 and 1920 plats with oats at Lin-
cluden, which occupied the same areas for the two years, the control
yields were as shown in Table 29, in which the relative yields of the
corresponding treated areas for the same years, the controls being
taken as 100, are also shown for comparison:

TABLE 29.—Comparison of the results of electrocultural experiments with oat crops
at Lincluden, England, in 1919 and 1920

Relative yields of elec-

Acre yields of control trified areas, the con-
plats (bushels) trols being taken as
Area 100
1919 1920 1919 1920
SPE] O) CWE Nh ees ahh EP PES 28s ARN NN ae ee 45.2 44.8 80 80
DE SB Et ee ee eee 43.8 46.1 102 94
11) BRAS URES ak ofS Rie i SP OS ieee ee: SNS | 28. 9 33. 0 184 156

It is obvious that the yields of the third section of the control

‘ area were aly low compared with the yields of the other

control sections and that this fact is almost certainly involved in
the high percentage increases arising for the third section of the
treated area. It would therefore appear that these particular
increases may be attributed to a lack of soil uniformity, and the
importance of this unknown factor is indicated.

he most consistent series indicating favorable response to electrical
treatment appears to be the 1918 oat trials at Lincluden. The plats |
in oats at Lincluden gave the average annual yields shown in Table

The yields from the electrified areas in 1918 seem to have been
sa exceptional compared with the electrified areas for the three
other years that one may question whether it is justifiable to attri-
bute the increase solely to the electrical treatment.

; ELECTROCULTURE

29

TasiLe 30.—Analysis of the average results of electrical treatments of oat plats at
Lineluden, England, in the years 1917 to 1920, inclusive

Average acre yields | Average acre yields
(bushels) Ratio of || (bushels) Ratio of
Year treated to) Year | treated to
‘ control | a control
Treated | Control ] Treated | Control
a 446, 44.0 EO 1919-2: 45.0| 39.3 1.14
ott ae 80. 2 | 53. 6 ea Ae 5 SS 43. 8 | 41.3 1. 06

The instances specifically considered in Tables 29 and 30 comprise
the most notable of the percentage increases reported by Blackman,
as shown in Table 28, and they are therefore in a large measure the
basis of the 22 per cent average increase reported. One is thus left
without definite assurance that the field experiments demonstrate
a favorable response to the electrical treatment.

The pot-culture experiments in England by Blackman and his
associates gave results which are summarized in Table 31.

TaBLe 31.—Resulis of electrical pot-culture experiments with grain crops in Eng-
land, according to Blackman

| wy ae Ratio of bape ah eer Ratio of
Year and crop treated to | Year and crop : ‘treated to
| ‘Treated | Control | COmtrol — Treated Control | C='rol
| |
|
essa | 0. 72 f 0. 98 =e f 66 | L07
L 72 5 < 15.
Wheat —--------- i ¥ 71 f 0. 73 j E 7 i Maize Late a at a at a i 15. 39 \ 14. 52 { j 05
i | 1. 43 |} 1.02 | 1) 23.84 | 99
Maire. ----* =. 1.21 ( 1.39 87 | Barley 2. (| 23. 28 23. 88 | .97
teh ehr-s | Caer] eee cee
212 | 2. 30 . 92 | Wheat _________ 17.11 16. 22 | 1.05
Harioy = =". 1.98 - 86 | 18. 76 f L15
97 *75 | 1921:
id ee [ #2} may ie
8.12 104 | | 340 \ sis H 1.07
8.37 7.78 1.07 | 7.2 =! 1.18
Maire. =. **" 7.41 - 95 || Barley_--_____- 49.2 | 1.05
10. 84 1. 26 | 53. 0 46.5 1.13
10. 36 8. 54 Li i 48. 5 - LO
10. 85 L2 | i} 51.9 1.11
1919: | iL 22.8 21.2 | 1.07
f 5. 70 5. 62 1.01 15.5 = .99
1 6.81 aie ae | eens i} wef eH co
Maize. 272 ae | 2. 32 | CO erases fe es 18. 20 \ 16. 60 { 1.09
16. 73 - 96 |) 18. 95 ; 1.14
16. 17. 28 At 2 .
15. a . 86 || Average______ be. 3 32 eee 1.01
13.72 | 73 ||
Barley________- J 15. 84 18. 69 | 8 ||
| 11.75 (16.89 | 69 | | |

As with the tabulated values for field experiments, so here also the
results of the pot-culture trials represent more than the electric dis-
charge variable; soil and seasonal factors vary as well as the crop
and the duration, nature, and strength of the electrical treatment.
Making a comparison, 26 trials out of 47 give positive results, while
21 give negative results. The treated piaaee return yields repre-
sented by the range 73 to 127; when the untreated plants return a
pele represented by 100 and give an average increase of 1 per cent.

is increase is well within the experimental error, and the pot-
culture trials in their entirety thus furnish no definite evidence of a
response to the electrical treatment.

80 BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE | .
i

In contrast to the field experiments, however, the pot-culture trials
afford results from several similarly treated pots and plants, so that
an estimate of individual experiments may be made by comparing
the differences between treated and untreated plants with the prob-
able errors involved in the measurements.

When the pot-culture records are examined in this way, it becomes
evident that the treated and untreated plants present substantial
differences. With uniform soil and seasonal factors for electrified
and control plants the association of these differences with the
treatment becomes intimate. The fact that these differences favor
the control plants about as often as the treated plants emphasizes
the complexities involved and makes one less certain that these
differences are definitely attributable to the electric discharge.

The laboratory experiments of Blackman and his associates have
been on the effect of a direct current of very low intensity on
the rate of growth of the coleoptile of barley. Differences in the
growth rate of treated and control plants were noted over short
periods. The small differences attributable to the direction of the
current and the pronounced after effects obtained make the inter-
pretation of the data difficult and uncertain.

In general, then, one finds in Blackman’s experiments many
significant differences between the electrified and control plants.
In some instances the relation of the discharge to these differences
may well be questioned. In others the relation appears to be an
intimate one, and the significance of such differences is the immediate
concern of further research in electroculture.

4

TABLE 32.—Summary of electrocultural trials

]
|

Definite influence reported No definite influence reported
Method eo ae : - ae
Year Observer Year Observer
| ey
Soil-conducted currents:
1889__--- La cb pe ee creas 1893__=_- de fa
‘eer 1892__._- | aalepster --. 3 Set 2 abe 1899_____ _ Ahilfvengren.
Germination ----------- fe ah ES | etaney 2 Se | 1902_____ Flammarion.
1902' >. .| Plowman *. 33". 2. - = oe 19052 02% Lowenberg.
1892: 52.2 Wiartlen 2 i242 5) eke 1846____- Solly.
Pop cultures: 22 > 2° 5! {i903 Bo-5| BROOD: . = 2455 ee we he eee
phe Hemberger 28 2: i... 32 ae ee
1360: == _ [. Mitehiner.. \ east. ee 1883-87__| Wollny.
Mield trials; - 2. :e-o*_ 18885 oe Holdefieisss pies = 19072._© Gassner.
1844_____ Ross: *. 2 Je Realy 2 tae 1909_____ Gerlach and Erlwein.
Soluble plant food_____- FSG 222u2 Mezoron~ =. Oe ee 5 ale Cele
Modified atmospheric po-
tential gradient:
1904 2 Lemstrémes: 2-5... 224
1905-1911; Lodge, Newman_________- 1O072 5°53 Gassner.
1013 3290 Diorseyesss eee eae 10097 S33: a and Erlwein.
‘ |} 1914_____ Jérgensen, Priestley, | 1909-1910) Breslauer.
Increased potential_..- | Dudgeon. jc ee Hostermann.
TOT E Le Clausen.
1k by eee Blackman, Liverpool en- | 1918-1924; Briggs, Campbell, Heald,
gineers . Flint.
1876: 252. Masearticen 4 3 ren 8 1880___-- Laikewicz.
Decreased potential -_- IBi S224 Grandestie> Se aeae ses 1914 =< Briggs and Shantz.
1910S 22 HostermaAnne!? ets 22-4) 2b

A review of the literature of electrocultural experimentation u
to the present time does not lend assurance of great progress. (Table
32.) In 1800 Senebier (45) wrote substantially as follows:

ELECTROCULTURE 31

The researches of Maimbray, Nollet, Bose, Menon, and Jalabert would
indicate that electricity accelerated the development of plants, both in their
germination and in their subsequent development. Nuneberg, many years
afterward, repeated the same experiments with the same results. Linné and
Kostling observed the same effects. Achard confirmed these results. Berthelon,
in a treatise on the electricity of plants, has summarized the information on the
subject and substantiated it by further research of his dwn. Gardini, from work
carried on at Lyon, affirmed the influence of electricity on vegetation. Carmoy,
d’Ornoy, and Rosieres have defended this opinion in the Journal de Physique.
These doctors base their conclusions on the identity of natural and artificial
electricity, on the continual electrified condition of the atmosphere, and on the
meteorological phenomena which indicate in a more or less sensitive manner
the presence of electricity; the different elevated parts of plants, which are ip
themselves excellent conductors of electricity, offer in their leaves, as De Saussure
has observed, the proper points to receive the electric fluid. ... All these
experiences led to the opinion stated when Ingenhousz published experiments
which proved that electricity would not produce the effects upon plants which
had been attributed to it; that electrified seeds ®* would not germinate quicker
than others. These experiments, reported in the Journal de Physique for
December, 1785, were confirmed in the same journal for December, 1786, were
given further support in May, 1788, and were finally summarized in “ Expéri-
ences sur les végétaux.’”’ Various other workers later confirmed these re-
searches. It seems to me at present [1800] that the opinion of those who believe
that electricity does not favor vegetation is more logical than the contrarv
opinion.

At the present time (1924), there is still a diversity of opinion
concerning the influence of electricity in plant development. The
electroculture committee of the British Ministry of Agriculture and
Fisheries recommends (1923) the continuation of experiments with
high potential discharge,’ Newman (38) in England considers
electroculture by the same method as offering practical assurance
of increased returns. Baines (1) points out a wonderland of electro-
biological relationships. On the other hand the experiments of
Gerlach and Erlwein (19, 20) in Germany and the experiments
reported in the first part of this bulletin show no increased growth
definitely attributable to electrical treatment.

2 & Leighty and Taylor (#1) report experiments with electrified seed which indicate no advantage gained
y treatment.
7 Typewritten report on file in the Office of Biophysical Investigations, Bureau ot Plant Industry.

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LITERATURE CITED
Barings, A. E.
1921. Germination in its electrical aspects. 185 pp., illus. London
and New York.

Basty, F.
1908. Essais d’électroculture tentés & Angers en 1908. (Extrait.) In
Bul. Soc. Etudes Sci. Angers, ann. 37 (1907), pp. 87-92.
BERTHELOT, M.

1889. Recherches nouvelles sur la fixation de l)?Azote par la terre
végétale. Influence de l’électricité. In Compt. Rend. Acad.
Sci. [Paris], tome 109, pp. 281-287.

BLACKMAN, Vii.
1918-1924. [Electrical treatment of fields.] Gt. Brit. Min. Agr. and
Fisheries Interim Rpts. 1-6 (1917-23). [Mimeographed.]

1924. Field experiments in electro-culture. Jn Jour. Agr. Sci., vol. 14
(1923), pp. 240-267.

and JgRGENSEN, I.
1917. The overhead electric discharge and crop production. Jn Jour.
Bd. Agr. [London], vol. 24, pp. 45-49, illus.

and Lreag, A. T.
1924. Pot-culture experiments with an electric discharge. Jn Jour.
Agr. Sci., vol. 14, pp. 268-286, illus.

and Ganka B.C;

1923. The effect of a direct electric current of very low intensity on the
rate of growth of the coleoptile of barley. Jn Proc. Roy. Soce.,
London, ser. B, vol. 95, pp. 214—228, illus.

BRESLAUER, M.
1912. Amount of energy needed for electro-culture. Jn Electrician,
vol. 69, pp. 889-890.

Briaes, L. J.. and SHantz, H. L.
1913. The water requirement of plants. I. U. 8S. Dept. Agr., Bur.
Plant Indus. Bul. 284, 49 pp., illus.

1914. Relative water requirements of plants. Jn Jour. Agr. Research,
vol. 3, pp. 1-63, illus.

CuRER, C.
1910. Atmospheric electricity. Jn Ene. Brit., vol. 6, pp. 860-870,
illus.

CLAUSEN. y
1911. Die Erfolge der Elektrokultur in Hedewigenkoog. Jn Landw.
Wehnbl. Schles.-Holst., Jahrg. 61, pp. 83-86.

DupcEon, E. C.
[1912]. Growing crops and plants by electricity. 36 pp., illus.
London.

ELFVING, F.
1882. Ueber eine Wirkung des galvanischen Stromes auf wachsende
Wurzeln. Jn Bot. Ztg., tebe 40 (1881), pp. 257-264, 273-278.

FITCHNER, E.
1861. Agronomische Zeitung, 1861, p. 550. [Not seen. Reference
from Bruttini, A., L’ influenza dell’ elettricit’ sulla vegeta-
. zione, p. 148, Milano, 1912.]

GASSNER, G.
1907. Zur Frage der Elektrokultur. Jn Ber. Deut. Bot. Gesell., Bd.
25, pp. 26-38, illus.

1909. Pflanzenphysiologische Fragen der Elektrokultur. In Mitt.
Deut. Landw. Gesell., Jahrg. 24, pp. 5-7.

32

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ELECTROCULTURE 33

GERLACH, M., and ERLWEIN, G.
1910. Versuche ueber Elektrokultur. Jn Elektrochem. Ztschr., Jahrg.
17, pp. 31-36, 66—68, illus.

1910. Versuche tiber die Einwirkung der Elektrizitat auf das Pflanzen-
wachstum. Jn Mitt. K. Wilhelms Inst. Landw. Bromberg,
Bd. 2, pp. 424-453, illus.

GRANDEAU, L.
1878. De Vinfluence de l’électricité atmosphérique sur la nutrition des
plantes. (Extrait.) Jn Compt. Rend. Acad. Sci. [Paris], -
tome 87, pp. 60-62, 265-267, 939-940.

H6sSTERMANN.
1910. Geschichte und Bedeutung der Elektrokultur unter Beriick-
sichtigung der neueren Versuche. -Jn Arch. Deut. Landw.,
Jahrg. 34, pp. 535-570.

HOLDEFLEIss.
1885. Elektrische Kulturversuche. Jn Centbl. Agr. Chem., Jahrg. 14,
pp. 392-393.

HomBERGER, E.
1914. Behandlung von Pflanzen mit MHochfrequenzstrémen. In
Umschau, Jahrg. 18, pp. 733-735, illus.

Honcamp, F.
1907. Die Anwendung der Elektrizitat in der Pflanzenkultur. Jn
Fiihling’s Landw. Ztg., Jahrg. 56, pp. 490-499.

J@RGENSEN, I., and Priester, J. H.
1914. The distribution of the overhead electrical discharge employed
in recent agricultural experiments. Jn Jour. Agr. Sci., vol. 6,
pp. 337-348, illus.

KInnNeEY, A. 8S.
1897. Electro-germination. Mass. Hatch Agr. Exp. Sta. Bul. 43,
32 pp., illus.
K6vesssI, F.
1912. Influence de ]’électricité 4 courant continu sur le développement

des plantes. Jn Compt. Rend. Acad. Sci. [Paris], tome 154,
pp. 289-291.

LEICESTER, J.
1892. The action of electric currents upon the growth of seeds and
plants. Jn Chem. News (London), vol. 65, p. 63, illus.

1892. Action of an electric current upon the growth of seeds. In
Chem. News (London), vol. 66, p. 199.

Leienty, C. E., and Taytor, J. W.
1924. Electrochemical treatment of seed wheat. U. S. Dept. Agr.
Cire. 305, 7 pp., illus.

LEMSTROM, S. :
1904. Electricity in agriculture and horticulture. 72 pp., illus.
London and New York.

Lopes, O.
1908. Electricity in agriculture. Jn Nature, vol. 78, pp. 331-332,
illus.

1911. The mode of conduction in gases illustrated by the behaviour
of electric vacuum valves. Jn Phil. Mag. and Jour. Sci.,
ser. 6, vol. 22, pp. 1-7, illus.

MaccaGno, J.
1880. Influenza dell’ elettricita atmosferica sulla vegetazione della
vite. In Staz. Sper. Agr. Ital., vol. 9, pp. 83-89.

Mascart, E. E.
1876. Traité d’ électricité statique. 2 vol., illus. Paris.
Newman, J. E.

1911. Electricity as applied to agriculture. Jn Electrician, vol. 66,
pp. 915-916, illus.

34
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=
BULLETIN 1379, U. S. DEPARTMENT OF AGRICULTURE

1922. Electricity and plant growth. Jn Standard handbook for
electrical engineers, Ed. 5, pp. 1810-1811. New York. :
PAULIN.
1892. De |’ influence de l’électricité sur la végétation. Montbrison.
Not seen. Reference from Bruttini, A., L’influenza dell’-
elettricita sulla vegetazione, p. 216. Milano. 1912.]

PLowMaAN, A. B.
1902. Certain relations of plant growth to ionization of the soil.
In Amer. Jour. Sci., ser. 4, vol. 14, pp. 129-132, illus.

1903. Electromotive force in plants. In Amer. Jour. Sci., ser. 4,
vol. 15, pp. 94-104, illus.

PRIESTLEY, J. H.
1907. The effect of electricity upon plants. Jn Proc. Bristol Nat.
Soc., ser. 4, vol. 1 (1906), pp. 192-203.

1910. Overhead electrical discharges and plant growth. Jn Jour.
‘Bd. Agr. [London], vol. 17, pp. 16-28.

Ross, W.
1844. Galvanic experiments on vegetation. U. 8S. Comr. Patents
Rpt., vol. 27, pp. 370-378, illus.

SENEBIER, J.
[1800.] Physiologie végétale. 5 vols. Genéve.

Souuy, E.
1846. The influence of electricity on vegetation. Jn Jour. Hort. Soe.
London, vol. 1 (1845), pp. 81-109.

Wiuson, C. T. R.
1923. Atmospheric electricity. Jn Glazebrook, R., A dictionary of
applied physics, vol. 3, pp. 84-107, illus.

Woutny, E. .
1888-1893. Elektrische Kulturversuche. Jn Forsch. Agr. Phys.,
Bd. 11, pp. 88-112, 1888; 16, pp. 243-267, 1893.

ORGANIZATION OF THE
UNITED STATES DEPARTMENT OF AGRICULTURE

December 22, 1925

memrearyoo, Agriculiure.________._..___.- W. M. JARDINE.

BT 21g | re R. W. DUNLAP. .

Mueener a, Sctentijic Work__.....___...+- —_——_——_——

Director of Regulatory Work__-__- Ret eae Water G. CAMPBELL.
Director of Extension Work_-_.-.._._._______-- C. W. WARBURTON.
Director of Tnformation_____- ___.....___.- NELSON ANTRIM CRAWFORD.
_ Director of Personnel and Business Adminis-

ne Bee a i ee W. W. STOCKBERGER.

0 TL a ee R. W. WILLIAMS.

emer bureau... sips See CHARLES F. Marvin, Chief.
Bureau of Agricultural Economics_______ ~~~ Tuomas P. Coopnr, Chief.
Bureau of Animal Industry___--------- __. JoHN R. Mouter, Chief.
purcag a, tian Indusiry_-_.._- _- -.__-___- WiuuiaM A. Taytor, Chief.
1 ee ae a W. B. GREELEY, Chief.
Pemmereerre Remtisiry: = C. A. Browne, Chief.
a ae ee ae MILTON WHITNEY, Chief.
purenmo, Pniomology.___.__-__._.__-__--__- L. O. Howarp, Chief.
Bureau of Biological Survey____---_------- E. W. Netson, Chief.
Pemuen mere Rodds_.__._ 2. -_______~ Tuomas H. MacDonatp, Chief.
Bureau of Home Economics_-_-_-_----------- Louise STANLEY, Chief.
ee TYTN. = Le C. W. Larson, Chief.

Fixed Nitrogen Research Laboratory -------- F. G. Cotrretu, Director.
Office of Experiment Stations______-------- E. W. ALLEN, Chief.

Office of Cooperative Extension Work_-_- ---- C. B. Smita, Chief.

[oo SS a ee CLARIBEL R. BARNETT, Librarian.
Pederal Horticultural Board____.....------ C. L. Maruatt, Chairman.
Insecticide and Fungicide Board____------- J. K. Haywoop, Chairman.
Packers and Stockyards Administration _- --- JOHN T. CaINnz, in Charge.
Grain Futures Administration_------------ J. W. T. DUvVEL, in Charge.

This bulletin is a contribution from

area Lead Industry... __.__...._..---- Wituram A. Taytor, Chief.
Office of Biophysical Investigations _ - --- G. N. Couuins, Senior Botanist in
Charge.
35

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