Title Page

Group Title: Department of Soils mimeographed report
Title: Do you need manganese in your fertilizer?
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00091554/00001
 Material Information
Title: Do you need manganese in your fertilizer?
Alternate Title: Department of Soils mimeographed report 56-1 ; University of Florida
Physical Description: 4 leaves : ; 28 cm.
Language: English
Creator: Fiskell, John G. A
University of Florida -- Agricultural Experiment Station
Publisher: University of Florida, Agricultural Experiment Station
Place of Publication: Gainesville, Fla.
Publication Date: October 1955
Subject: Fertilizers -- Florida   ( lcsh )
Manganese -- Florida   ( lcsh )
Soils -- Manganese content -- Florida   ( lcsh )
Plants -- Effect of manganese on -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: by John G.A. Fiskel.
General Note: Cover title.
General Note: "October, 1955."
 Record Information
Bibliographic ID: UF00091554
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 310122083

Table of Contents
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Full Text

Department of Soils Mimeographed report 5E $6-1

October, 1955

Do You Need Manganese in Your Fertilizer?


John G. A. Fiskel

University of Florida
Agricultural Experiment Station
Gainesville, Florida


All plants require manganese as part of their nutrient diet. Regard-

less of how much nitrogen, phosphorus, or potash, or perfect growing

weather the plant is exposed to, a small amount of manganese must get into

the plant as it grows. In most soils there is a sufficient supply of

manganese for plant needs, In other soils, the plant has difficulty

obtaining enough manganese and such cases are found usually in alkaline

soils such as the marl soils of Florida or in peaty muck soil in the

Everglades. This leads in severe cases to manganese deficiency symptoms

on the leaves which are characterized by small, yellowish leaves often

with small dark spots about the size of a head of a pin. In less severe

cases, the plants look green but are unable to give the yields that would

be obtained if the soil supplied sufficient manganese.

In contrast some soils supply manganese very readily to the crop,

which may result in the manganese content in the plant being very much

higher than the average content. This leads in severe cases to manganese

toxicity, characterized by stunted growth and for some species, dark spots

on the leaves about the size of the head of a match, often accompanied by

a yellowing not unlike iron chlorosis.

How are you to know if you need manganese in your fertilizer? If you

are farming in an area where manganese deficiency has been identified by

your county agent or Agricultural Experiment Station personnel, then you

are also likely to have areas on your farm too low in manganese. It pays

to inquire if other growers in your area are putting in manganese with

their fertilizer. Another guide is if the pH of the soil is above 6.5,

then your soil may be suspected of requiring manganese. This is not always

* Radio Talk, WRUF, given October 2k, 1955.


the case especially in the heavier soils of West Florida. Fortunately,

manganese can be applied in the fertilizer without damage to the crop even

on soils having already a high status of manganese availability. This has

been demonstrated for several crops at the West Florida Experiment Station

and in tests conducted at other locations in the State. This means that

when you apply fertilizer containing manganese on your soil, you may

benefit the crops growing on land too poor in manganese and at the same

time you won't be injuring the crop on land which is giving the crops a

sufficient supply of manganese. For instance, some citrus soils have in-

creased in manganese from a few pounds per acre up to several hundred

pounds per acre without evidence that manganese is becoming toxic.

This tolerance of manganese by thecrop happens to be where the pH is

kept up by a good liming program or where the soil can control the availa-

bility of a large amount of manganese. Such soils are the peats, muck,

alkaline soils and sandy loams. Other sands might not do sell if the

manganese were to get too high, because a high manganese availability

along with low fertility is known to be undesirable. In such cases liming

and high fertility are recommended. Another reason for crops tolerating a

wide range of manganese in the soil is that manganese is the least toxic of

the minor elements, the order of toxicity being usually nickel, copper,

cobalt, boron, chromium, zinc and molybdenum, before manganese.

Sources of Manganese

How much manganese do you need in your fertilizer? The answer depends

on the manganese your soil is supplying the crop. The answer also depends

on the source of manganese put into the fertilizer. Unit for unit,

manganous sulfate or manganous (green) oxide is a much better source of

supply than manganese (black) dioxide or other manganese oxides. These

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latter forms are likely to be too inert for the crops to obtain much

benefit, if any. If your soil needs a good supply of manganese in the

fertilizer, specify the source of manganese to be manganous sulfate or

manganous oxide. Otherwise, cheap but inefficient substitute sources may

be used. On soils definitely deficient in manganese, land being brought

into cultivation for the first time will need a total of 20 units of

manganese, or if you specify one unit (MnO) in the fertilizer mixture you

need to apply then one ton of such fertilizer. On the marls in South

Florida and in some of the Everglades peaty muck, yearly application of

manganese has been found to be necessary. Your local Branch Experiment

Station should be consulted in these areas. On soils where manganese is

of doubtful supply, such an application might only be made once, relying

upon the s oil to store the applied form in an available state for several


Experimental evidence has been obtained that the oxides release their

manganese slower than manganous sulfate in sandy soil and thereby are safer

to apply, especially if high rate of application (80 to 120 units MnO) were

attempted. On manganese-deficient marl or peaty muck such high rates can

be used, with manganous sulfate being a slightly better but more expensive

source than powdered manganous oxide and both much superior to powdered

gamma manganese dioxide ore.

In fertilizer mixtures containing organic such as Chicago sludge,

peanut hulls and castor pomace, some manganese is being supplied from these

materials. Other fertilizer materials contain a very small amount of

manganese. For some crops on some soils this small amount of manganese in

the fertilizer might be sufficient in addition to the amount supplied by

the soil. Data are not available on the quantity of manganese in such

fertilizer mixtures or its sufficiency as a supply to crops. The same

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applies where crops are dusted with a fungicide containing manganese.

Manganese consumption in fertilizer mixtures is about 300,000 units

per year. Increase in the use of manganous oxide in these mixtures and

a decrease in the use of other manganese sources has been found in a

recent survey of mixing companies in Peninsular Florida.

Where manganese is necessary for top yields and top quality and where

soil manganese is not available in sufficient amounts, guaranteed amounts

and source of manganese in your fertilizer are your insurance of your

crop getting its proper manganese nutrition. However, soil holds most

of the manganese applied if the pH is above 5.0. Caution is advised to

avoid adding too much manganese yearly or over a period of years.

100 Copies
October 21, 1955
Soils Department

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