Organic Soils

THE EFFECT OF MANGANESE SULFATE ON SEVERAL CROPS GROWING ON ORGANIC SOILWHEN APPLIED IN SOLUTION AS A STREAM OR SPRAY ON THE CROP1

PAUL M. HARMER AND G. DONALD SnERMAN2

MUCK soiL,3 with its very high proportion oforganic matter, has long been recognized as

being very low in content of the mineral elementsneeded for plant growth. In the earlier days of ferti-lization with minerals, the only two which were recog-nized as being absolutely necessary for crop produc-tion on muck were phosphorus and potassium. Withinrecent years, however, considerable benefit has beensecured on these organic soils by the application ofsoluble salts of several of the less commonly used butapparently highly important elements, such as boron,copper, manganese, sodium, and zinc.

Benefits from the use of manganese sulfate, appliedin the soil on several crops, was first reported bySjollema and Hudig (n).4 Among those who firstused manganese sulfate in solution and who reportedcontrol of chlorosis and increased crop yields, weshould mention Gilbert, McLean, and Hardin (3),who sprayed oats, spinach, beets, and beans on heav-ily limed soil; Mann (8), who sprayed soybeans onhighly alkaline sandy loam, McLean (9), who fedmanganese salts through the stomata by spraying;McLean and Gilbert (10), who sprayed spinach onheavily limed, nearly neutral soil; Lee and McHargue(7), who applied spray to diseased sugar cane leaveson Hawaiian soil to aleviate Pahala blight; and Bry-an (i), who painted cowpeas and soybeans on Flor-ida Everglades soil.

EXPERIMENTAL PROCEDURE

The complete report of the work carried on in this studyis too voluminous to be given in this paper. Therefore onlyrepresentative portions are presented and a more detailedaccount will be published later in bulletin form. Althoughstudies on the effects of manganese sulfate applied in solidform on Michigan organic soils were first begun in 1924(4), the effects produced by its application in solution werenot investigated until 1934. In the early experiments the useof sulfur as a corrective was also investigated (5) and, fromthe standpoint of economy in those days, it was more fre-quently recommended for the unproductive alkaline areas.Trials, were then conducted to determine the strength ofmanganese sulfate solution which could be used withoutinjury to crops on alkaline muck soil. In 1934, 1935, andJ936, the solution was applied in a stream on the row ofgrowing plants. In 1937 and later years, the applications weremade as a spray. Except where noted, the manganese sulfateused in all these experiments was of the finely ground com-merical grade, containing approximately 65% MnSCU. With-

out doubt a considerable proportion of this manganese sulfatewas not dissolved but remained in a suspension in the solutionused. In 1941 the material was a little finer than previously,having been passed through a 325-mesh sieve. Except asindicated, soils, on which these studies were carried on, wereall located on the 14-acre muck experimental field on theCollege farm at East Lansing. Description of the depth, soilpH, organic matter content, and drainage conditions of thedifferent sets of plots on this field is given in Table I. Soils Iand 2 were burned over many years ago, No. I having beenrendered decidedly alkaline.

These studies were of necessity limited to some extent bylack of space. Where the trials were continued in succeedingyears, the land was plowed about 10 inches deep and the plotslaid out at right angles to those of the preceding year, sothat all treatments crossed all plots of the preceding year.Insofar as could be seen, there was little or no residual effectfrom the relatively small amounts of manganese, included inthe spray experiments of the preceding years.

Application in stream.—In 1934 trials were conducted ontwo alkaline mucks, one (soil No. i, Table i) in InghamCounty and the other in Ionia County. Soil pH in both caseswas around 7.8 and the onions were curled and chlorotic.In both trials the use of 25 pounds manganous sulfate (C.P.)in 500 gallons water, applied as a stream on the crop row,gave a response visible within 48 hours and the yield benefitmuch greater than was secured with any other treatmentmade. In 1936 a similar study on alkaline shallow muck inClinton County doubled the yield of onions, 25 pounds manga-nese sulfate giving better results than 50 pounds when dis-solved in 450 gallons water.TABLE i.—Depth, soil pH, state of decomposition, organicmatter content, and moisture conditions in four sets of spraying

trials on College muck plots, East Lansing, Mich.

SoilNo.

i

2

3

4

Approx-imatedepth

ofmuck,feet*

1-5

3-5

12. 0

15.0

Plowed layer

SoilPH

7-4-7-8

6.5-7.0

6.0-6.4

5.8-6.0

State of de-composition

Well decom-posed

Well decom-posed

Moderatelydecomposed

Rather raw

Av.or-

ganicmat-ter

con-' tent,

60

70

80

85

Drain-age

in wetperiods

Poor

Fair

Fairlygood

Good

Mois-ture

supplyin dryperiods

Dry

Dry

Fair

Good*Muck underlain by blue clay.

Contribution from the Soil Science Section of the Michigan Agricultural Experiment Station, Michigan State College, EastLansing, Mich.

2Research Professor in Soil Science, Michigan Agricultural Experiment Station; and formerly Graduate Assistant in SoilScience, Michigan State College, now Assistant Chemist, Southern Regional Research Laboratory, New Orleans, La., respectively.

3The term "muck" as used in this study refers to that group of soils having a very high content of organic matter in a more orless well-decomposed condition, but the conclusions drawn have been found to apply to most organic soils of similar pH, eventhough quite peaty in nature.

4Figures in parenthesis refer to "Literature Cited", p. 340.

334

HARMER AND SHERMAN: MAGNANESE SULFATE ON ORGANIC SOILS 335

Application in spray.—In 1935, a spraying program wasbegun on the College muck plots with manganese sulfate onpotatoes, and in later years several other crops, includingonions, sugar beets, beans, tomatoes, celery, and cucumbers, .were included in the study. The rate of application varied,of course, with the amount of foliage at the time of spraying.In 1935, 1936, and 1937, spraying was purposely not begununtil the foliage showed a decidedly chlbrotic condition,otherwise several of the treatments probably would haveproduced greater yields.

Bordeaux mixture has long been used in control of theblight diseases of potatoes and celery. More recently it hasbeen found effective in the prevention of leaf spot of sugarbeets and of downy mildew of onions. Since preliminarystudies in 1936 indicated that the manganese sulfate mightwell be included in the bordeaux mixture, it was used asthe basic spray in 1937 and later years. Inclusion of manga-nese sulfate in the bordeaux was at first accomplished bydissolving it with copper sulfate before adding the lime.In later experiments, it was dissolved in the previously madebordeaux mixture, with apparently equally good results. Toconserve space, the 1938 and 1939 data are purposely omittedin this report.

RESULTSPOTATOES

Trials (Table 2) carried on with potatoes in 1938and 1939 on alkaline soil (soil i, Table i) includedcommercial manganese sulfate in the bordeaux sprayat several concentrations. In the spray mixturesshown in this and later tables, the proportion ofmanganese sulfate is expressed as a number addedat the end of the bordeaux formula. The inclusionof manganese sulfate showed a very marked increasein yield over the use of the standard bordeaux with-out manganese. Yield increased, with increase inamount of manganese sulfate added, up to 8 poundsper 100 gallons bordeaux, with a slight decrease inthe 1938 yields when 10 pounds was used.

TABLE 2.—Effects of MnS04 added in different amounts tobordeaux spray on potatoes on alkaline soil*

TABLE 3.—Effect of MnSO$ added to bordeaux spray onpotatoes on slightly acid soil, 1938 *

Orderof

dupli-cateplots

PoundsMnSO4 per

100 gals.bordeauxmixture*

Total yield,bu. per acre

Plotgroup

1-6 7-12

Av.

Av.in-

creaseovercon-trol,

No. itub-ers,

Av.weight

perNo. ituber,

oz.

19381,72,84. IO6,123,9 .5,n

8-I2-IOO-O8-1 2-1 00-28-12-100-48-12-100-68-12-100-88-12-100-10

55189198218233217

891 80219235254203

721852092272442IO

——156189214239194

296775697672 '

3-34-34.64.64-64-4

19391,52,63,74,8

8-6-100-08-6-100-48-6-100-68-6-100-8

2303233293?i

304281364366

267302347369

7233i

65656770

4-24.03-93-8

*Soil pH 7.6-7.8. Dates of planting: 1938, June 6; 1939, June 2. Datesof spraying: 1938, July 12, 16, 26, 28. Aug. 22 and 25; 1939, June 29, July 8,

PoundsMnSO4 in100 gals,bordeaux

None . . . .2. . . . . . . .

Total yield, bu. per acre

Plot

A

90171

B

245260

C

275356

D

301344

E

302443

F

289285

G

217254

H

i°5142

Av.9plots

228282

Av. in-creasefrom

MnSO4, %

23-7

19, 31 and Aug. 10.fNo. I size includ':es all tubers 2 inches or more in diameter.

*Soil pH 5.8-6.0. Planted May 20; sprayed July n, 16, 21, 28, and Aug.9.

A third experiment in 1938 consisted of the spray-ing of potatoes (Table 3) on a slightly acid muck(No. 4, Table i), having a pH range of 5.8 to 6.0 inthe plowed layer, with a drop to 5.0 in the secondfoot. Manganese sulfate, applied on adjoining plotsas part of the fertilizer mixture, had benefited no cropof the several grown, including potatoes. Alternaterows were sprayed with bordeaux and with manga-nese-bordeaux, the rows crossing a series of plotsthat varied somewhat in the phosphate-potash ferti-lization received. This variation is reflected in adifference in yield from plot to plot. The manganese-bordeaux gave better color of tops on all plots andbetter yields, on seven of the eight plots, than didthe straight bordeaux, the average of all plots showingan increase of nearly 24%.

Potato spraying trials on soil No. 2 were carriedon from 1938 to 1941 inclusive (Table 4). Plot iin 1938 was sprayed with water to which sufficientlime was added in the early season sprays so that thecalcium arsenate, which was included for beetle con-trol, would produce no injury.

Although a marked benefit was secured in 1938from the use of ordinary bordeaux (Table 4) on thesefaintly acid plots, the effects from the inclusion ofmanganese sulfate were outstanding. Two poundsper 100 gallons of bordeaux generally appeared togive as good results as did four pounds. In the pres-ence of the manganese sulfate, a decrease in theamount of copper sulfate used did not give as goodresults in 1938 as did using the full amount, but thereverse was true in 1941. Reducing the hydrated limeto one-half the ordinary amount did not decrease theyield of potatoes in 1938 but appeared to produce aslight decrease in 1941. In all three years, the useof manganese sulfate in the bordeaux spray greatlyincreased both the percentage and the average weightof No. i size tubers. Application of manganese sulfatein the first half of the spraying season gave muchbetter results than when applied in the last half. Thespray gave considerably better yields in 1941 thandid the side dressing, but the combined soil and sprayapplication gave much better results than either ap-plied alone.

ONIONSA set of plots similar to those reported with pota-

toes in Table 4 was carried on with onions in 1938,1940, and 1.941. The yields secured (Table 5) were

336 SOIL SCIENCE SOCIETY PROCEEDINGS 1943

TABLE 4.—Effects on yield of potatoes of MnSOt applied as a sidedressing and in bordeaux spray in different amounts andat different times*

Plotorder

Lbs.MnSO4 in100 gals,bordeaux

No. sprays contain-ing MnSO4 and plotsreceiving sidedressingMnSO4 at 100 Ibs.

per acre

Total yield, bu. per acref

Plot group

A B CAv.

Av. increaseover control,

%

No. i sizetubers,

%

Av. per No.I size tuber,

oz.

I567432

1938, Soil pH 6.5-7.0; Sprayed 8 Timeso-o-ioo-o8-12-100-08-I2-IOO-28-I2-IOO-44-I2-IOO-44-I2-IOO-24-6-IOO-2

76300

673649613584481

116654692523492589

2473

846757594686716

50163724699577587595

-69

344329254260265

20.061.99O.68g.I9O.O88.289.6

2.23-85-96.15-75-65-9

1941, Sprayed 8 Times6, 8

4

532I

1079

8-6-100-08-6-100-0

8-6-100-28-6-100-28-6-100-48-12-100-44-6-100-28-6-100-28-6-100-2

No Mn sprayNo Mn spray

(sidedressed)All 8 (sidedressed)All 8All 8All 8All 8In first 4 spraysIn last 4 sprays

97167258215203238358307149

151220479277353450327315144

159278357294343369375318269

1352223652623003523533H187

——

64170 .94

12216116213339

7i,7

79-788.788.988.582.687.982.479-2

4.0

4-75-44-95-06.05-95-04.0

*Date of planting: 1938, May 21; 1941, May 16. Date of spraying: '1938, June 29, July 9, 16, 21, 28, Aug. 9, 12, and 25; 1941, June 28, July 7, 14, 22, 30,Aug. 7, 20, and 26.

fAnalysis for variance for 1938, F = i6.45; 1941, F=7.27. Number required for significance between means, for 1938=101.6; for 1941 =63.6.

rather low, due chiefly to the fact that the drainagewas hardly sufficient to permit of early seeding, withthe further result that the root development was rela-tively near the surface. As a result, the crop suffered

more from dry weather in later growth than wouldordinarily have been true and, consequently, was verypoor, both where no bordeaux and where ordinarybordeaux were used.

TABLE 5.—Effects of MnSOt applied on onions as sidedressing and in spray in different amounts and at different times*

Plotorder

Lbs. MnS04in 100 gallons

bordeaux

No. sprays containingMnSO4 or plots side-dressed with 100 Ibs.

per acre MnSO4

Total yield, bu. per acre

Plot groupf

A B C*

Av.

Av. over i^4inches indiameter,

%

Av. weight peronion over I %inches in size,

oz.

1938, Soil pH 6.5-7.0; Sprayed 8 Timesfo-o-ioo-o8—12—100-08-12-100-28-12-100-44-12-100-44-12-100-24-6-100-2

3IO

1552OI207155IOO

45328392392310235

i3

184 '281262241321

219

222291287235219

245865635463

1941, Soil pH 6.5-7.0; Sprayed 8 Timesf

0.91.62-32.42-52.32-5

6,. 84532I

IO79

8-6-100-08-6-100-08-6-100-28-6-100-28-6-100-48-12-100-44-6-100-28-6-1 00-28-6-100-2

NoneNone (sidedressed)All 8 (sidedressed)All 8All. 8All 8All 81,2,3,45,6,7,8

961421961741 86178250220139

1 88193335222244257269299244

• 79198309296345267270227123

121I78280231258234263249169

—————————————————

—— '————————————

• ————

*Dates of seeding: 1938, May 22; 1941, May i. Dates of spraying: 1938, June 29, July 9, 16, 21, 28, Aug. 9, 12, and 25; 1941, June 28, July 7, 14, 22,30, Aug. 8, 20, and 26.

fAnalysis for variance for 1938, F=i4.2; 1941, F =4.48. Number required for significance between means, for 1938=85.5; for 1941 =52.8.

HARMER AND SHERMAN." MANGANESE SULFATE ON ORGANIC SOILS 337

When manganese sulfate was included, a markedincrease in yield of marketable bulbs was secured,four parts of manganese sulfate giving a somewhatbetter return in all three years than did two parts.When manganese was included, reduction of the cop-per sulfate in the bordeaux to one-half the ordinaryamount did not result in a decrease in yield. Reduc-tion of the amount of hydrated lime did not give asignificant change. Inclusion of the manganese in thesprays used in the first half of the season gave muchbetter results than when used in the last half. Appli-cation of manganese sulfate as a sidedressing gavea marked increase over no manganese, but not ashigh a yield as was produced by the use of manga-nese in the spray. The combination gave higher yieldsthan did either treatment alone. (See Figs, i and 2.)

SUGAR BEETS

The use of the ordinary bordeaux spray on thesugar beet plots in 1938 (Table 6) produced anincrease of 2.5 tons per acre of roots, as well as3.3 tons increase in tops and crowns. The additionof manganese sulfate in the bordeaux at the rate of

FIG. 3.—Showing onions, potatoes, and sugar beet plotswhich had been given different sprays. All staked rowsand the plot at left center had received ordinary bordeaux,while the two rows (potatoes and beets) on the otherplots had received varying mixtures of manganese-bor-deaux. Note the difference in shades of color of the potatoes.Photographed July 12, 1938.

FIG. i.—Samples of soil from this newly reclaimed field weretaken by the grower in 1942 from the productive portionshown at the right. These samples, tested at MichiganState College, gave no indication of the presence of thehighly alkaline soil, deficient in available manganese, atthe left. Manganese sulfate applied in solution after severechlorosis of the onions had developed produced a fair yieldof what would otherwise have been a complete crop failure.

FIG. 2.—Showing effects of use of manganese sulfate onalkaline muck (soil No. i, Table i) applied in solution onthe rows of onions as soon as curling and chlorosis ap-peared (plot left of center stake), with no manganese onthe five rows at the right of, the stake, 1934.

FIG. 4.—Showing the growth at a later stage and from theopposite direction of the same set of plots as pictured inFig. 3. The staked rows and center plot received ordinarybordeaux, while the others received varying mixtures ofmanganese-bordeaux. Photographed August 24, 1938.

2 pounds per 100 gallons gave an increase in rootsover the straight bordeaux of 1.2 tons in 1938, 3.6tons in 1940, and 2.1 tons in 1941. The inclusionof more manganese sulfate produced no significantincrease in beets in 1938, but gave a 2-ton increasein 1941. Reduction in the proportion of copper sulfatehad no consistent effect on the yields of roots or tops.Including the manganese in the sprays of the last halfof 1940 gave better results than when included inthe first half, but the results were reversed in 1941.

When standard bordeaux was used in 1938, thepercentage sucrose was increased, and further, in-crease resulted when manganese was included in thespray. In 1941 there was no increase, probably be-cause the season was such as to induce a late renewedgrowth of tops on healthy beets, which growth gener-ally will reduce the sugar content of the beet. Theheavier manganese application gave more sucrosethan did the lighter. Recoverable sugar showed a verymarked increase, both from the use of bordeaux andfrom the inclusion of manganese in the bordeaux.5

5Pounds of recoverable sugar = pounds of beets Xpercentage sugar X coefficient of apparent purity.

338 SOIL .SCIENCE SOCIETY PROCEEDINGS 1943

TABLE 6.—Effects of MnSOt applied on sugar beets as a sidedressing and in boraeaux spray in different amounts and atdifferent times*

Plotorder

Lbs.MnSO4 in100 gals,bordeaux

No. sprays con-taining MnSO4 orplots sidedressedwith 100 lbs.,per

acre MnSO4

Yield, tons per acre

Roots (crowned) f

Plot group

A B CAv.

Av.topsand

crowns

Av.totalcrop

Sugar

Av.sucrose,

%

Av.recover-

able,poundsper acre

Avapparentpurity,

i567432 '

1938, Soil pH 6.5-7.0; Sprayed 8 TimesJo-o-ioo-o8-I2-IOO-O8-I2-IOO-28-12-100-44-12-100-44-12-100-24-6-100-2

10.813-613.914.214.314.215-2

——14.015-4H-515.613-714.4

10.4u.813-713-314-514.1H-3

10.6I3-I14-314.014.814.014.6

13-116.420.221. 118.119.219.2

23-729-534-535-132-933-233-8

16.918.919,220. i20.219-319.8

3,"44,4"4,8945,0465,2414,7765,053

1941, Soil pH 6.5-7.0; Sprayed 8 Times

87.089.188.889.487-588.687-3

6, 84532I

IO7

• 9

8-6-100-08-6-too-o8-6-100-28-6-100-28-6-100-48-12-100-44-6-100-28-6-1 00-2 •8-6-1 00-2

NoneNone (sidedressed)All 8 (sidedressed)All 8All 8All 8All 81,2,3,45 ,6 ,7 ,8

10.812.812.914.1H-313-512.815-413.7

12.413.614.213-316.012.414.915-312. 1

——————————————————————————

n.613.213.613-715-213.013-915-412.9

——————————————————

—————————— •——. ——————

15-415.516.014.815-515-915-215-815-6

2,9733,492

' 3,5963,2793,8853,5243,4964,0053,401

83.085.783.081.082.586.083.082.785.0

BEANS

Spraying trials were carried on with beans for 3years, the 1939 and 1941 results of which are pre-sented in Table 7. A very marked increase in growth

TABLE 7.—Effect of MnSO4 applied as sidedressing and inbordeaux spray on beans*

Orderof

plots

Bordeaux contain-ing MnSO4 (Ibs.

per 100 gals.) andplots receiving too

Ibs. per acreMnSO4 side-

dressed

Shelled beans,bu. per acre

Plot group

A B CAv.

1,7,134,10

In-creaseOvercon-trol,

1939, Soil pH 6.2; Sprayed 4 Times4-6-100-0 24.4 25.4 27.6 25.84-6-100-4 41.7 32.1 —— 36.9 301941, Soil pH 7.0-7.5; Sprayed 5 Times

6,135,123, 10

4, ii

1,8,152,97, H

o-o-o-o8-6-100-08-6-100-0

(sidedressed)8-6-1 00-2

(sidedressed)8-6-100-28-6-100-48-6-100-2 (first

two sprayings)

7.06.9

11.6

13-2

14.113-916.1

7-56-5

14.1

14-317.817.012.7

——————

——

n-5——

7-36.7

12.9

13-8

14-515-514.4

8——

92

105

"5130H5

was secured from the use of manganese sulfate inthe spray, 2 pounds per 100 gallons bordeaux givingas good results as did 4 pounds. (See Fig. 5.) Nobenefit to the crop was secured from the use ofbordeaux unless it contained manganese. Manga-nese sulfate applied as a sidedressing was decidedlybeneficial, but its inclusion in the spray gave evenbetter results. Combination of sidedressing and usein spray was no better than its use in the sprayalone. Inclusion of the manganese sulfate in the firsttwo sprays only gave almost as good results asincluding it in all.

*Dates of seeding: 1939, June 3; 1941, June 10. Dates of spraying:1939, July 3, 12, 28, and Aug. 16; 1941, July 7, 15, 28, Aug. 7 and 20.

FIG. 5.—On this slightly acid soil (pH 6.0-6.4), the stakedrows of beans, receiving manganese sulfate in bordeauxspray, were healthier and .yielded much better than thealternate rows which received ordinary bordeaux.

HARMER AND SHERMAN: MANGANESE SULFATE ON ORGANIC SOILS 339

TOMATOES

Two years of spraying trials with manganese wereconducted on tomatoes. In 1939 the plots were lo-cated on slightly alkaline (pH 7.0—7.5) and in 1940on .slightly acid (pH 6.0-6.4) s°il- Considerableresponse to manganese sulfate was secured in 1939,but 2 pounds in 100 gallons spray gave as good re-sults as did 4 pounds. Manganese produced a health-ier green color of leaves throughout the season. Onthe slightly acid soil in 1940, there were no consistentdifferences to indicate any benefit from the manga-nese application.

CELERY AND CUCUMBERS

Manganese sulfate, applied in bordeaux spray for2 years in the case of celery and i year with cucum-bers failed to produce consistent benefits. The celerytrials were located on soil 3 (pH 6.0-6.4) an<3 thecucumbers on soil adjoining soil i where the pHvaried from 7.0 to 7.5. Both crops showed improvedcolor but not increased yields. Two celery growershaving alkaline muck in the state tried out manga-nese sulfate ,in their spray and reported beneficialresults. Cucumbers grown in preceding years on soili (pH 7.6-7.8) showed greatly improved color, butno increase in yields when manganese sulfate wasapplied in the soil.

DISCUSSIONJustification for the use of manganese sulfate as

an ingredient in spray must be found either in a moreimmediate benefit from such an application over itsapplication in the soil, in a greater yield from thespray application, or in an equal benefit with a muchsmaller amount applied in the spray than if appliedin the soil. With most of the crops sprayed in thisinvestigation, all three of these advantages have beengained from the use of manganese sulfate as aningredient in the bordeaux. Frequently new muckfields are reclaimed and, without a soil test, the landis planted to some crop such as onions. The standmay look very good and prospects for a good yieldmay appear excellent for the first month or more ofgrowth. Then the onion tops begin to lean over andcurl downward, until many times the tips touch theground. Along with the curling, chlorosis of leaveswill develop. At this stage, it is too late to applysulfur to correct the alkalinity which is almost certainto be associated with this unnatural growth on prop-erly drained muck. Application of manganese sulfatein the solid form as a top or sidedressing may givesome benefit, but the benefit is likely to depend onthe amount of rainfall following that application.With the application in the spray, the benefits onboth ;onions and potatoes are immediate and, if ap-plied when the abnormal appearance first develops,the crop will return to normal color and growth andstill give a good yield. The plots on the East Lansingmuck, described in Tables 2, 4, and 5, were locatedadjacent to a third set of plots on which manganesesulfate was applied annually to the soil for eight years,

1934 to 1941, inclusive. Generally, onions and pota-toes were grown on these plots each year during thistime. Benefits from the manganese sulfate applicationto the soil on these plots never approached the resultswhich we secured on the adjoining plots from thespray treatments. Sugar beets grown on this set ofplots .appeared to be benefited by the manganesesulfate soil application in the early part of the sum-mer. By harvest time, however, the differences en-tirely disappeared and the yields of roots, tops andsugar were as good without the manganese appli-cation as with it. This same result has been securedwith sugar beets in trials on two other alkalinemucks in the state.

Manganese sulfate, applied broadcast to the soilon the acid side (pH 5.8-6.0) of the field on theCollege muck, has produced no benefit in trials withseveral crops. Yet, on the same part of the field,potatoes have showed considerable benefit from themanganese spray. Without question a more rapidand greater benefit, extending through a greater pHrange, can be secured by the use of manganese inthe spray than by a soil application. Further, thebenefits with the manganese-bordeaux have beenaccomplished with a much lighter application thanhas been required when the broadcast applicationwas used.

Although the potatoes on slightly acid muckshowed no increase in yield from the inclusion ofmore than two pounds of manganese sulfate per 100gallons of bordeaux, the yield of marketable tuberson the alkaline muck increased with increase in theamount of manganese sulfate used up to 8 poundsper 100 gallons. Likewise, sugar beets and tomatoesgave little or no response to manganese in the sprayon slightly acid muck, yet showed considerablebenefit on faintly acid or alkaline soil in the samedeposit not 30 rods away (data not presented). Theseresults suggest that the amount of manganese sulfate,which can safely be included in the spray, will de-pend on the reaction of the soil on which the crop isbeing produced. The higher the pH of the soil, thegreater will be the amount of manganese which thecrop can take without decrease in yield. Since thegreater the alkalinity, the greater the amount ofcalcium present in the cell sap, this appears to befurther confirmation of the need for a definite calcium-manganese balance (6). It should be pointed outthat, while small decreases in yield appeared in someinstances when the manganese sulphate concen-tration was increased above a certain point, therewas no indication of physical injury to any cropfrom the concentrations used in this study.

Although the spraying experiments which havebeen conducted have not been carried on for the pur-pose of determining the relative extent of diseasecontrol, observations each year showed that the foli-age was healthier with manganese in the spray thanwithout it. Both potato and onion tops maintaineda deeper shade of green throughout growth whenmanganese was present, as can be seen from Figs. 3and 4. Cooking tests showed that the eating qualities

340 SOIL SCIENCE SOCIETY PROCEEDINGS 1943

of the potatoes grown on the alkaline muck wereimproved when manganese was used in the spray.In the case of the sugar beets, the difference in colorof the tops was plainly visible although not alwayssufficiently great as to be discernible in a black andwhite photograph.

In the spraying of these experimental plots, aswell as on commercial fields, some difficulty has beenexperienced in the use of manganese sulfate in bor-deaux. This is due to the formation of gypsum bychemical reaction of the manganese sulfate andhydrated lime, which tends to clog the spray nozzles.This difficulty can be minimized by using the sprayas soon as the manganese sulfate is added and bycleaning the sprayer thoroughly after spraying.

SUMMARY

In a study begun on Michigan organic soil deficientin available manganese in 1934, and still continuing,the application of manganese sulfate, both whenapplied as a weak solution and fine suspension in astream on the crop row, and when added to bordeauxmixture applied as a. spray, has given outstandingbenefits on several" crops. Most notable have beenthose secured on potatoes, beans, onions, and sugarbeets, with some benefit on tomatoes. Observationsand yields led to the following conclusions:

1. Application of manganese sulfate in stream orspray gave very marked increases in yields of severalcrops, completely correcting chlorosis of tops, ordi-narily characteristic on alkaline organic soil, andproducing a more vigorous growth and healthy greencolor of foliage.

2. Spraying the crops with manganese increasedsize and improved eating quality of potatoes, in-creased size and hastened maturity of onions, in-creased yield of roots, sugar content and yield ofsugar beets and yield, number and size of bean pods.

3. Improvement in foliage color generally was evi-dent within 48 hours after application of manganeseon tops of onions, potatoes and beans, and shortlylater with sugar beets and tomatoes.

4. Manganese sulfate sprayed on the crops gavemuch 'more immediate benefits and, in general, higheryields' than when applied in the soil, indicating agreater efficiency of absorption through the leavesthan through the roots.

5. The results indicate that the greater the alka-linity of organic soil, the greater the proportion ofmanganese sulfate which can be safely included inbordeaux spray. They further indicate that manga-nese may be applied in the spray with beneficialresults on certain crops on organic soil having aslightly acid (pH 5.8-6.0) reaction on which anapplication in the soil ordinarily shows no beneficialeffects. It appears that the pH range of responsive-ness will vary with different crops.

6. Manganese applied in the spray on soil withpH 6.5 to 7.0 gave better results with potatoes andonions than was secured with manganese sidedressed,

but the combination was best. With sugar beets andbeans, manganese as spray was best.

7. With a soil pH of 6.5 to 7.0, increase in amountof manganese sulfate from two to four pounds per100 gallons increased yields of onions and generallyincreased yields of potatoes and sugar beets, but didnot increase yield of beans or tomatoes.

8. With manganese in the spray, reduction of theamount of copper from an 8-12-100 to a 4-12—100generally reduced the yield of potatoes, but did notaffect other crops.

9. Application of manganese in bordeaux sprayappears as a cheap and very effective way of using it.Observations showed that the crops were somewhatmore free from disease when sprayed with manga-nese-bordeaux than was true with the ordinarybordeaux.

10. Application of manganese in the bordeauxwas of greater benefit in a cool, wet season than ina hot, dry one and generally was more beneficialwhen included in the early sprays than in the lateones.

11. The results indicate that manganese in the bor-deaux by maintaining a proper calcium-manganesebalance may prevent the harmful effects sometimescaused by the lime, and that the manganese-bordeauxmay be found effective for use on certain crops onwhich ordinary bordeaux has proved injurious.