Dublicate
BULLETIN 301 DECEMBER 1956

Reapoase

of

CROPS to LIME
in A4labama

STATION EXPERIMENT AGRICULTURAL INSTITUTE POLYTECHNIC Oihde ALABAMA
E. V. Smith, Director Auburn, Alabama

CONTENTS
Page
INTRODU CTION -------------------------------

3

Calcium and Magnesium-- -- - -- --- --- - - -3 So il A c id - - ---- --------------- ---------------- 4 --So il p H -- -- --- ------- -------- - ------- -- -- --- 4 Effects of Lime --- -- --- -- -- --- ------ -- -- - -- - 5 O ver-Lim ing -- - - - ------------5----------Lime Requirements of Different Soils-6 Lime Requirements of Different Crops-8
-

COTTON-8----

Experimental Results ---------------CORN-18----PASTURE LEGUM ES ---SOIL IMPROVING ----------AND

---

-10

---

---

---

-18 25

LEGUMES -

WINTER
AND

SUMMER-

G R ASSES -- - - - - - --- -29-ALFALFA, SWEET

- -- - - -- -- -- - - - - -- CALEY PEAS

CLOVER,

--------------- 33

P E ANU T S -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3 7

Peanut Soils Are Rapidly Exhausted--------------------37 Restoring Exhausted Peanut Soils----------------------38 Alabama's Peanut Soils Need Lime--------------------38 Understanding the Peanut-Soil Lime Problem ---------- 40 Soil Lime and Peanut Yields--------------------------40 Soil pH and Peanut Yields .------------------------- 42 Per Cent Sound Mature Kernels and Peanut Yields-------43
SOYBEANS FOR O IL --------------------------RECOM M ENDATIONS
------------------------------------

--------

44

45

FIRST . PRINTING 4M,

DECEMBER 1956

~edft4%4e

%&

CROPS

to

LIME

FRED ADAMS, Associate Soil Chemist

INTRODUCTION the growth of plants. factors Aproperties ofaffecting govern growth are factors thatThe various man must plant soil
NUMBER

determine and control if he is to realize optimum returns from his land. One of the most important properties of a soil is its storehouse of available plant nutrients.
CALCIUM AND MAGNESIUM

Just as with nitrogen, phosphorus, and potassium, calcium and magnesium must be replenished when the supply available to the crop has been seriously reduced. Calcium and magnesium are usually supplied to the soil in the form of lime. In agricultural terminology, lime usually refers to calcium and/or magnesium carbonate. The commonly used liming materials are listed in Table 1.
TABLE 1. LIMING MATERIALS AND THEIR EQUIVALENT NEUTRALIZING VALUES

Kind High calcitic lime Dolomitic lime Ground shells Basic slag Blast furnace slag Calcium silicate slag Flue dust (lime-ox)

Pounds of material equivalent to 1 ton of pure calcium carbonate 2,100-2,850 1,850-2,100 2,200-2,500 2,800-3,000 2.700-3,000 2,700-3,000 2,100

Other available plantrnutrients

8-10% P20 5 3% K 0
2

The data reported by the author are from field and laboratory investigations by the Agricultural Experiment Station of the Alabama Polytechnic Institute extending over a 25-year period. The experiments were conducted by members of the Department of Agronomy and Soils working cooperatively with Superintendents of the Substations and Experiment Fields, and with farmers.

4

ALABAMA

AGRICULTURAL

EXPERIMENT STATION

SOIL ACID

As calcium and magnesium are removed from the soil, their place is taken by soil acid. Observing farmers have known for many years that sour soils could be made sweet by adding lime. The word sour denotes the presence of an acid, whereas sweet implies the absence of an acid. Acids are ordinarily thought of as being liquids, such as the acid in sour milk, the acid in lemon juice, or the acid bought in a bottle from the druggist. However, soil acid is different - it is not a liquid. If soil acid were liquid, rainwater would leach it from the soil as it moved down through the soil to the water table below. Actually, the soil particles themselves make up soil acid. However, it is only the very small soil particles (clay and organic matter) that can become soil acid. When rocks first begin to decay and soil begins to form, the process of acidification sets in. The rate of acid production is affected by environment under which the soil develops. The percolating water moving through the soil dissolves and carries with it a quantity of bases (non-acids), namely calcium, magnesium, and potassium. As these bases are removed from the soil, they are replaced by soil acid. Thus, soils become acid rapidly in a climate such as found in Alabama where the rainfall is abundant. Many of Alabama's soils originated from materials containing an abundance of lime and contained adequate lime when first cultivated. However, losses by leaching and continuous cropping have depleted many soils of their supply of lime. Thus, such soils have become acid and nonproductive.
SOIL PH

Chemists devised a means of determining the strength of acid present and introduced the symbol "pH" to mean acid. The strength of the acid was then identified by adding a number to the symbol "pH." A devised pH scale ranges from 0 to 14. The exact middle of this scale, pH 7, is where there is no excess acid. This is the pH of pure water. If there is excess acid, the pH will be below 7. The greater the acidity, the smaller the pH number becomes. These same values have been adapted for use in expressing the strength of soil acid. Soil pH is actually a measure of the percentage of clay and organic particles that have become acid. A soil with pH 7 is said to be neutral. If the soil pH is less than 7,

RESPONSE of CROPS to LIME

5

the soil is acid. If the soil pH is greater than 7, the soil is alkaline. The pH value of soils in Alabama varies widely from calcareous soils (about pH 8) to very acid soils (less than pH 5). Acidity of the majority of Alabama soils falls between pH 5 and pH 6. For most crops, a soil pH between 6 and 7 is desirable.
EFFECTS OF LIME

Proper use of lime will replenish the soil's supply of calcium and magnesium as well as neutralize the accumulated soil acid. Thus, lime not only adds essential plant nutrients, but it also conditions the soil so that plants derive greater benefits from other plant nutrients present. In addition to the foregoing functions, lime added to an acid soil will (1) increase the availability of phosphorus and molybdenum (an essential minor element), (2) promote the growth of useful soil micro-organisms, (3) influence the plant's uptake of potassium, and (4) reduce the availability of iron, manganese, boron, and zinc (essential elements for growth of plants).
OVER-LIMING

There have been many instances where adding lime to an acid soil has actually reduced crop yields. This is not the usual effect of lime, but it does occur sufficiently often that an explanation is required. Reduced yields will occur on soil in which both lime and other plant nutrients have been reduced to a very low level. At high pH values resulting from liming, the amounts of iron, manganese, boron, and zinc available to the plant are reduced. This occurs because the solubility of these particular plant nutrients decreases with increasing pH. These plant nutrients are required in small amounts but are essential. Therefore, in a soil where the quantity of one or more of the above plant nutrients are dangerously low, the increased pH caused by the lime reduces the amount of the plant nutrient in question to the point where the plants cannot absorb all they need. In addition, an application of lime may increase the plant's demand for potash. An application of the plant food in short supply will correct the socalled, "over-liming injury" and the benefits of lime are realized. In Alabama, soils usually need an application of potassium, boron, or zinc where over-liming damage occurs. Over-liming usually occurs where too much lime has been added at one time. This can be avoided by a soil analysis, which will indicate how much

6

ALABAMA AGRICULTURAL EXPERIMENT STATION

lime and other plant nutrients should be added to the soil to realize optimum benefit from the lime.
LIME REQUIREMENTS OF DIFFERENT SOILS

There is no present means whereby visual appearance of a soil or growing plants will give a measure of needed lime. The only safe and accurate way of determining a soil's need for lime is a laboratory test for pH and lime requirement. The pH of a soil is a measure of how strong the soil acid is, but it is not a measure of the total amount of soil acid present. This can only be determined by knowing the pH of the soil and the amount of clay and organic matter present. A clay soil will have considerably more soil acid than a sandy soil with the same pH value. Thus, the pH of a soil and the amount of soil acid must be known for judicious use of lime. Since materials from which the soils of Alabama developed differ, types of soil and their present lime status also vary. In general, the agricultural land of Alabama can be divided into five soil areas, Figure 1. These areas are (1) Coastal Plains, (2) Black Belt, (3) Sand Mountain, (4) Limestone Valley, and (5) Piedmont. The Coastal Plains is the largest single soil area. Its soils are acid with most having a pH of less than 6. Lime requirements differ sharply since the clay contents vary. Black Belt soils are clays. The pH values of these soils vary considerably. Some are very acid with a pH of less than 5, whereas others have a pH of over 8. These high pH soils were developed from Selma chalk, which is sufficiently high in lime to be used as a liming material. Just how acid the surface soil is depends upon the depth of the soil above the chalk. The shallow gray soils are high in lime with a pH of 8 or above. The deep black soils of the low areas are about neutral. Intermixed with these calcareous and neutral soils are heavy acid clay soils. Most of these soils have a pH of about 5.0 to 5.5. Sand Mountain soils were developed from sandstones that produced mostly sand and little clay. Little lime was present in this region so that soils with a low pH cover the area. The low pH indicates the need for lime and the low clay content indicates the need for small amounts of lime at any one time. Limestone Valley soils are those that occur in areas where limestone was the dominant rock from which the soil developed.

RESPONSE of CROPS to LIME

7

LEGEND

0li Limestone Valleys LZ1Appalachian Plateau
SUpper

Coastal

Plains

Coastal Plains QI Piedmont Plateau
' Black Belt

EjLower

FIGURE 1. Soil areas of Alabama and their locations.

8

ALABAMA

AGRICULTURAL EXPERIMENT STATION

They are present in northern and northeastern Alabama and are represented by the Tennessee Valley, Coosa Valley, and many smaller valleys. These soils were developed from material high in lime, but cropping and leaching have made many of them quite acid. The Piedmont soils are the oldest in the State. Fertility of these soils varies considerably. The pH, clay content, and lime requirements also vary within the region. In general, these soils are moderately acid.
LIME REQUIREMENTS OF DIFFERENT CROPS

Just as soils vary in their lime requirement, crops differ widely in their need for lime as a nutrient and in their abilities to grow at low soil pH. Most crops will grow well in soils with a pH of 6 to 7. Alfalfa has as high a lime requirement as any crop grown in Alabama, requiring a soil pH of about 7. Such crops as carpetgrass and lespedeza grow well in quite acid soils. Since both soils and plants vary in their need for lime, the lime requirements of various Alabama crops will be discussed according to soil area and crop. COTTON The cotton plant is tolerant of moderate amounts of soil acid. However, small but profitable yield increases from liming are frequent on moderately acid soils. Large yield increases will not result from liming until sufficient soil acid has accumulated for the soil pH to be between 5.0 and 5.5. Cotton is frequently grown in rotation with a legume so that lime is actually beneficial to cotton in two ways: (1) an increased
supply of calcium and magnesium and (2) the increased supply

of other soil nutrients, particularly nitrogen, resulting from the increased organic matter produced by the legume receiving lime. The cotton-producing soils, as a rule, have been relatively well fertilized in the past. The fertilizers used have contained small supplies of calcium and magnesium as superphosphate or dolomitic limestone. Dolomitic limestone is added to mixed fertilizers in manufacturing non-acid-forming grades. Thus, lime has been added annually in small amounts to cotton lands. This is why, in general, only small gains in cotton yields have been realized from direct applications of lime. With increased usage of acid-forming

RESPONSE

of CROPS to LIME

9

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FIGURE 2. Effect of lime on cotton on an acid Magnolia sandy loam at Monroeville. Top-unlimed; bottom-lime applied.

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10

ALABAMA

AGRICULTURAL

EXPERIMENT

STATION

EXPERIMENTAL RESULTS

Results from several years of experiments with lime applications have shown that cotton yields were increased by liming most Coastal Plains soils, Table 2. No lime was needed at Aliceville for cotton production, since the soil already contained adequate calcium and magnesium as indicated by its pH of 6.3. Annual yield increases of about 300 pounds per acre of seed cotton were obtained from adding lime at Brewton and Monroeville where the soil pH was 5.8 and 5.6, respectively. Soil at Prattville had a higher pH and showed only a slight, though profitable, increase in cotton yields from lime, Tables 2 and 4. Results of experiments on the sandy soils of the Wiregrass Area (Headland) showed that small but frequent lime applications increased the yield of cotton, whereas a large application may have induced "over-liming" damage, Tables 2 and 4. In soils where lime content is critically low, the use of higher rates of fertilizer will further exaggerate the lime need of cotton (see Table 2, Brewton and Monroeville locations). As higher rates of fertilizer are used on cotton, the yield increases brought about by liming become even greater.
TABLE 2. EFFECT OF LIMESTONE ON THE YIELD OF SEED COTTON IN A 2-YEAR ROTATION WITH VETCH AND CORN AT VARIOUS SITES DURING A 25-YEAR PERIOD

Average annual seed cotton yield per acre Treatment Aliceville' 1930-48' Unlimed Limed 1949-558 Unlimed Limed pH of unlimed soil in 1946
1

Coastal Plains Coastal Plains Brew- Monroeville 2 ton' Lb. 1,139 1,241 1,481 1,754 Lb. 1,220 1,875 1,556 1,809

soilsLimestone soils CrossPratt- Headville 5 ville 3 land 4 'ndria' Lb. 1,397 1,447 1,585 1,595 Lb. 1,412 1,450 1,708 1,646 Lb. 1,750 1,879 1,524 1,549 5.6

Valley soils Belle AlexMina6 Lb. 1,204 1,148 1,334 1,870 6.0 Lb. 1,562 1,450 1,434 1,894 6.0

Lb. 1,475 1,486 1,165 1,185

6.3

5.8

5.6

5.9

5.8

Kalmia sandy loam. sandy loam. ' Greenville sandy clay loam. Norfolk sandy loam. 5 Hartsells fine sandy loam. 6 Decatur clay loam. All plots received 100 pounds nitrate of soda, 600 pounds superphosphate, and 75 pounds muriate of potash per acre per rotation. 8 All plots received 400 pounds nitrate of soda, 800 pounds superphosphate, and 100 pounds muriate of potash per acre per rotation.
2 Magnolia

RESPONSE

of

CROPS

to

LIME

11

The amount of acid-forming nitrogen fertilizers used is continually increasing. Unless these materials are effectively neutralized, the soil becomes more acid and less fertile with continued use. However, adequate liming in conjunction with the use of these fertilizers gives excellent cotton yields, Table 3. Cotton yields were almost doubled at Monroeville and Headland when lime was used with ammonium sulfate. The need for lime was not as great when ammonium nitrate was used. Nevertheless, lime was needed with ammonium nitrate on acid soils. There is no doubt that increased use of acid-forming fertilizer materials will require even more lime. Liquid and anhydrous ammonia applied on acid soils will also require neutralization with lime. It made little difference whether the lime was drilled in small amounts for each cotton crop or whether a larger broadcast application was made every few years except possibly at Headland, Table 4. Cotton is not grown to any extent on the heavy Black Belt soils of Alabama. Where cotton is grown in the Black Belt, it is usually found on the sandy soils scattered through that area. Liming practices for cotton on these soils should be the same as for the Coastal Plains soils.
TABLE 3. ROTATION WITH CORN EFFECT OF LIME ON COTTON GROWN IN NITROGEN FERTILIZERS AT FOUR RECEIVING ACID-FORMING AND

DIFFERENT SITES,

1946-1953

Average annual yield of seed cotton per acre
Nitrogen fertilizer'

Limestone added per acre

Coastal Plain soils

Crossville4 Lb. 1,448 1,504 154 1,570

Limestone Valley

Ammonium nitrate Ammonium nitrate
Ammonium sulfate Ammonium sulfate

None 8,000 lb.6 None 281 lb. each rotation

Monroeville2 Lb. 1,311 1,482 794 1,438

Headland3 Lb. 891 939 587 988

Belle5 Mina Lb. 1,564 1,622 1,419 1,608

pH of unlimed soil with ammonium sulfate in 1954 pH of unlimed soil with ammonium nitrate in 1954

5.1

4.4 5.1

5.0 5.3

1All plots received 600 pounds per acre of 8-10-10 per rotation. 2 Magnolia sandy loam. Norfolk sandy loam. 4 Hartsells fine sandy loam. 5 Decatur clay loam. 6 Lime applied once in 1946.

12
TABLE 4.
COTTON IN

ALABAMA

AGRICULTURAL

EXPERIMENT

STATION

EFFECT OF LIME OVER 20 YEARS ON AVERAGE ANNUAL YIELD OF SEED
A 2-YEAR ROTATION WITH CORN AND VETCH AT FOUR DIFFERENT SITES

Limestone applied, rate per acre, and method' None Drilled every 2 years 200 pounds 400 pounds 600 pounds Broadcast every 10 years 1,000 pounds 2,000 pounds 3,000 pounds pH of unlimed soil in 1940
2 4

Average annual per-acre yield of seed cotton, 1930-1949 Prattville2 Headland3 Crossville Belle Mina5

Pounds
1,407 1,428 1,547 1,467 1,458 1,456 1,470 5.6

Pounds
997 1,218 1,157 1,012 1,204 1,020 954 5.4

Pounds
1,374 1,478 1,544 1,477 1,499 1,497 1,431 5.0

Pounds
1,670 1,710 1,747 1,697 1,707 1,701 1,684 5.4

1600 pounds per acre of 6-8-4 applied to all plots in each rotation.

loam. ' Norfolk sandysandy loam. Hartsells fine
5 Decatur clay loam.

Greenville sandy clay loam.

Soils of the Sand Mountain Area produce satisfactory cotton yields where adequate fertilization is practiced. The lime requirement of cotton grown on these soils fertilized with non-acid fertilizers has been small. Over a 20- to 25-year period, lime applications at the Sand Mountain Substation, Crossville, resulted in small cotton yield increases, irrespective of whether lime was applied frequently in small amounts or in larger amounts less frequently, Tables 2 and 4. The lime need of cotton is greatly increased on these poorly buffered soils by use of acid-forming fertilizers. In an 8-year experiment at the Sand Mountain Substation, the average yield was 154 pounds of seed cotton per acre
from annual applications of ammonium sulfate. When lime was

applied with the ammonium sulfate, the yield of seed cotton averaged 1,570 pounds per acre, Table 8. Much of the soil found in the Limestone valleys is supplied with adequate calcium and magnesium (lime) for production of cotton. Soil at Alexandria with a pH of 6.0 showed practically no need of lime for cotton. A soil with the same pH in the Tennessee Valley gave similar results, Tables 2 and 4. The acid soils of these valleys, however, need lime. A Tennessee Valley Substation soil made acid by the continued use of ammonium sulfate gave an average increase of almost 200 pounds of seed cotton per acre where lime was added, Table 8.

RESPONSE

of CROPS to LIME

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TABLE 5.

EFFECT OF LIMESTONE ON THE YIELD OF CORN IN A 2-YEAR ROTATION WITH COTTON AND VETCH AT VARIOUS LOCATIONS IN THE STATE, 1930-1954

Treatment

Aliceville' Kalmia sandy loam 41.9 42.9 37.5 37.6 6.3

Yield of corn grain in bushels per acre Coastal Plains soils 3 3 Headland 1 Prattville Monroeville Brewton" Hartsells Norfolk Greenville Magnolia Kalmia fine sandy sandy sandy sandy clay sandy loam loam loam loam loam 38.8 42.3 50.6 54.1 5.8 42.3 42.5 50.0 54.2 5.6 46.6 44.8 47.1 44.9 5.9 34.4 33.8 33.2 33.2 5.8 54.4 56.1 70.2 71.2 5.6

Limestone Valley soils Alexandria Decatur clay loam 26.8 34.0 35.4 32.6 6.0 Belle Mina4 Decatur clay loam 40.5 42.0 50.9 52.3 6.0
i-

r

1930-486 Unlimed Limed
1949-546

r

Unlimed Limed pH of unlimed soil in 1946
SOne

0 c C I--.
C
i-

ton of lime each in 1929 and 1954. SOne ton of lime each in 1929, 1939, 1954. SOne ton of lime each in 1929, 1933, 1954. STwo tons of lime in 1929 and 1 ton in 1954. SCorn received 100 pounds of nitrate of soda per acre and the complete fertilizer was added to cotton in the rotation. 6 Corn received 200 pounds per acre of nitrate of soda and cotton received a complete fertilizer in the rotation.

r

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RESPONSE

of

CROPS

to

LIME

15

with lime on corn show no need for lime because the soil's deficiency of zinc was not corrected. Most experiments with lime on Coastal Plains soils have been with corn yields of 50 bushels per acre or less. With such yields, the benefit from lime has been less than 10 bushels. Limed soil at Brewton, growing 50 bushels of corn or less, has consistently yielded about 4 to 5 bushels per acre more than unlimed soil, Tables 5 and 9. Corn yields at the Wiregrass Substation have been low in most of the past experiments with lime. However, small drilled applications of lime every year or two have increased the acre yields by 2 to 5 bushels, Tables 6 and 7. Broadcast applications of a ton of lime or more have had no effect, or have actually reduced corn yields at the Wiregrass Substation, Tables 5, 6, and 9, unless zinc sulfate was added with the lime, Table 9. Lime has had little effect on corn yields at Aliceville (pH 6.8), Prattville (pH 5.6 and 5.9), Monroeville (pH 5.6), and Auburn (pH 5.5), Tables 5, 6, 7, and 8. The soil at the Main Station, Auburn, actually produced about 10 bushels less with lime than without lime or with lime plus zinc sulfate, Table 8. Several cooperative field tests with lime and the minor nutrients on corn were conducted in 1955 on Coastal Plains soils. Lime was beneficial, especially as the yields became greater, Table 10.
TABLE 6. EFFECT OF DIFFERENT LIME RATES AND METHODS OF APPLICATION THE YIELD OF CORN GROWN IN A 2-YEAR ROTATION WITH COTTON AND VETCH, 10-YEAR AVERAGE ON

Limestone amount applied, and method'

Average yield of corn grain per acre Crossville Belle Mina Headland Prattville 1940-492 1980-393 1940-49' 1940-49s Bushels 50.3 51.2 51.7 49.3 52.0 50.9 49.5 5.6 Bushels 25.9 29.4 27.8 25.8 29.4 27.2 25.7 5.4 Bushels 40.4 50.8 53.9 53.5 51.5 53.3 55.3 5.0 Bushels 51.5 52.6 54.1 52.8 52.2 55.1 53.4 5.4

None Drilled every 2 years 200 pounds 400 pounds 600 pounds Broadcast every 10 years 1,000 pounds 2,000 pounds 3,000 pounds pH of unlimed soil in 1940

1 No fertilizer was added to corn, but 600 pounds per acre of 6-8-4 was added to cotton in the rotation. 2 Greenville sandy clay loam. SNorfolk sandy loam. ' Hartsells fine sandy loam. SDecatur clay loam.

16
TABLE

ALABAMA AGRICULTURAL EXPERIMENT 7.

STATION

EFFECT OF LIME ON THE YIELD OF CORN GROWN IN ROTATION WITH
RECEIVING NITROGEN FERTILIZER AS AMMONIUM NITRATE

COTTON

OR AMMONIUM SULFATE,

1946-58

Nitrogen fertilizer

Average yield of corn grain per acre Limestone added per acre Monroeville 2 Bushels Headland3 Bushels 21.2 23.6 19.0 23.7 5.1 Crossville' Bushels Belle Mina Bushels 40.8 40.4 38.2 38.5 5.0 5.3

Ammonium nitrate Ammonium nitrate Ammonium sulfate Ammonium sulfate Ammonium sulfate Ammonium nitrate

None 3,000 pounds in 1946 None 281 pounds annually pH of unlimed soil in 1954 pH of unlimed soil in 1954

48.38 48.4 44.8 45.8

87.4
41.3 21.7 37.1 4.4 5.1

1Cotton received 600 pounds per acre of 8-10-10 in the rotation. 2 Magnolia sandy loam. Norfolk sandy loam. SHartsells fine sandy loam. 6 Decatur clay loam.

'

TABLE 8. EFFECT OF LIMESTONE AND BLAST FURNACE SLAG WITH AND WITHOUT MINOR ELEMENTS ON THE YIELD OF CORN GROWN IN ROTATION WITH CRIMSON CLOVER, 1947-49

Lime addedinor

Kind

Amount per acre Pounds None 4,000 4,000 4,000 4,000 4,000 4,000

Minor elements added

elements

Average yield of corn per acre

Auburn 2 Bushels 41.5 42.5 40.5 41.0 31.5

Boaz

3

Camp Hill Bushels 30.6 40.7 45.9 43.8 52.7 51.2 45.6 5.8

Coarse slag Medium slag Agricultural slag Agricultural limestone Agricultural slag Agricultural limestone pH of unlimed soil

None None None None None B, Zn, Mn
5

Bushels 26.7 41.8 40.2 47.2 42.0 49.2 48.6 5.1

51.1 41.5 5.5

B, Zn,Mn

'All plots received 300 pounds per acre of 0-14-10 annually. 2Norfolk sandy loam. SHartsells fine sandy loam. 4 Lloyd sandy clay loam. 55 pounds of borax, 10 pounds of zinc sulfate, and 10 pounds of manganese sulfate.

RESPONSE

of

CROPS

to

LIME

17
ON CORN YIELDS ON

TABLE 9.

EFFECT OF LIME

Two

COASTAL

PLAINS

SOILS,

1954-55 Limestone added Zinc sulfate added per acre per acre Pounds None None 1 ton None None 10 1 ton 10 pH of unlimed soil pH of limed soil 1 Kalmia loamy sand. 2 Norfolk sandy loam. Yield of corn grain per acre 1954 Brewton' 1955 Bushels 52.5 53.4 50.4 52.2 4.9 5.8 Headland 1954 Bushels 47.0 37.5 47.0 49.5 5.8 6.5
2

Bushels 23.6 28.1 22.6 28.4

The greatest benefit from lime was realized on most fields when zinc sulfate was added, the greatest yield increase being 19 bushels per acre. Corn is usually grown only on the sandy soils of the Black Belt area. The lime needs for these soils are the same as for the Coastal Plains soils. Corn yields are usually increased several bushels by liming Sand Mountain soils. Yields frequently have been increased 10 to 20 bushels per acre by a lime application, Tables 5, 6, 7, and 8, whether drilled in small amounts frequently or broadcast in larger amounts less frequently. A very acid soil (pH 4.4) resulting from the use of ammonium sulfate produced only about one-half as much corn as did the limed soil, Table 7.
TABLE 10. EFFECT OF LIMESTONE AND ZINC ON THE YIELD OF CORN GROWN COOPERATION WITH FARMERS ON SOME COASTAL PLAINS SOILS, 1955 IN

Liming program'

Zinc sulfate added per acre Pounds 0 0 10 10

Yield of corn grain per acre Auburn Union AuurnSprings Thomasville Inverness Lochapoka 6 Bu. 54.0 58.6 55.2 62.9 5.5 nitrate.

Bu. Bu. Bu. Bu. 34.5 99.9 75.6 53.9 37.3 91.2 78.9 65.6 33.4 108.2 79.9 54.1 Unlimed Limed 37.5 112.0 82.3 72.8 pH of unlimed soil 5.4 6.0 5.8 5.4 pH of limed soil 6.0 6.4 1400 pounds per acre 4-12-12 and 300 pounds per acre of ammonium 2 Lakeland sand on farm of George Baker. Kalmia fine sandy loam on farm of J. W. McCall. Farm of O. W. Nichols. SNorfolk loamy sand on farm of J. T. Cope. SNorfolk loamy sand on farm of G. C. Calhoun. Unlimed Limed

18

ALABAMA AGRICULTURAL EXPERIMENT STATION

TABLE 11. EFFECT OF LIME AND MINOR ELEMENTS ON YIELD OF CORN GROWN IN ROTATION WITH LESPEDEZA ON DICKSON SILT LOAM, LIMESTONE COUNTY

Limestone added per acre Pounds None 1,000 3,000 5,000 7,000
1 2

Yield of corn grain per acre Without
minor elements

With Bushels 41.6 41.9 45.0 44.6 45.3

Bushels 32.8 31.6 27.9 20.0 5.2

1941 yields from plots receiving 600 pounds per acre of 6-0-0. 1946 yields from plots receiving 600 pounds per acre of 6-8-8. The minor elements applied were boron, zinc, and magnesium.

Some soils of the Limestone valleys have a pH of 6 or above and need no lime for corn production, Tables 5 and 7. These soils were fairly well supplied with native lime so that added lime had little effect on the corn crop. However, slight yield increases have resulted from liming soils at the Tennessee Valley Substation, Tables 5 and 6. On the gray lands of the Tennessee Valley, lime had a considerable effect on, corn yields, Table 11. Yields were increased by liming, provided the other plant nutrients were adequately supplied. "Over-liming" damage was severe in one experiment where the minor nutrients were not added. Field tests for lime needs of corn in the Piedmont area are insufficient for results to be reliable. On an acid soil of pH 5.8, corn grown in rotation with crimson clover produced 30 bushels per acre on unlimed soil, whereas a lime application increased the yield to more than 50 bushels per acre, Table 8. Some, if not most, of the increased corn yields resulted from the increased nitrogen added by higher crimson clover yields on the limed plots. PASTURE LEGUMES (White Clover, Crimson Clover, Lespedeza) Pastures are the bases for economical production of meat or milk. Many of the less satisfactory returns from pasture feeding may be traced to a misunderstanding of soil fertility problems. In the past, the Black Belt Area has been considered the major pasture section of Alabama. However, pasture production in other areas of the State is important. Even though climatic adaptation of pasture plants is vital, an understanding of the soil

I

0
O

z IA
m TABLE 12. EFFECT OF LIME ON FORAGE PRODUCTION OF WHITE CLOVER-GRASS
SOILS

PASTURE MIXTURES

GROWN

ON COASTAL

PLAINS

t
In
O

Limestone added per acre' Pounds 0 2,000 38,000 4,000 6,000 pH of unlimed soil

Site 12 1945-50 green forage Pounds 9,278 13,507 12,944 6.5

Site 23 1950-51 dry forage Pounds 2,689 3,332 3,478.. -6.2

Average annual yield of forage per acre Site 34 Site 45 1948-52 1952-54 dry forage dry forage Pounds 2,045 2,028 Pounds 1,740 1,870

Site 5 6 1952-54 dry forage Pounds 3,894 5,428

Site 67 1943-44 dry forage Pounds 238 1,458 1,402 5.4

Im

----

2,236-5.7 5.4

plots received adequate applications of phosphate and potash. 2 Wickham fine sandy loam on Henderson Brothers' Farm at Miller's Ferry. sandy loam at Lower Coastal Plain Substation. Sluka silt loam at Upper Coastal Plain Substation. SIzagora fine sandy loam on Warren Farm at Comer. 6 Susquehanna fine sandy loam on Brabham Farm at Comer. ' Norfolk sandy loam at Auburn.

'All

'Wickham

0

TABLE 13.

EFFECT OF LIME ON FORAGE PRODUCTION OF WHITE CLOVER-GRASS PASTURE MIXTURES IN THE BLACK BELT AREA

Average annual yield of forage per acre Limestone added per acre' Site 12 1950 dry, hay Site 22 1950 dry hay Site 32 1950 dry hay Site 43 1949-53 dry hay Site 54 1943-46 1950-52 green hay dry hay Site 6' 1943-52 green hay Site 76 1944-46 green hay

Pounds
0 2,000 4,000 6,000 8,000----16,000 pH of unlimed soil
1

Pounds
1,868 1,586 2,420 2,146

Pounds
5,212 6,113

Pounds
4,614

Pounds
---3,391 4,044 4,927 -5.0

Pounds
21,560 25,652 28,746 28,165 27,218 4.6

Pounds
4,426 4,348 6,138 5,556 5,430-----

Pounds
1,372 12,623 10,782 17,252 4.7

Pounds 5,976
6,416 8,282 --C

5,654

5,466 5,859---------_-----

5.2

5.2

5.3

2 3

4Susquehanna clay loam. 'Oktibbeha clay on Moss Farm at Lamison in Wilcox County.
6

Adequate phosphate and potash applied to all soils. Vaiden clay at Marion Junction. Lufkin clay at Catherine. Leaf silt loam on Colley Farm near Safford.

m

z -I

0

z

RESPONSE

of CROPS to LIME

IGUR'E 4. White. clover ot lef is unlimcd (pH 5.4; of lime. Soil is Susquehaonno fine sandy loom.

plot at righit received

2 tons

(cds is j

it as

it i itii

t

. [I Aii i r

iti 11arI tS
ini

am 4ilN sp

i 'it-(

1c(511nl

Ims i)o

1ii1'I~l (iii.' t11111(5 td is 14 -

ii t14( tl.

;'j

sli 551 -l- i

tI IrJ

i

Ii

tis

ita

i

lsi .

i

Is

alfr df~i 'iri

d

(;al \\u

ri

s r a' c iitdrso

plc wit I~c l"[wdrI ltii I l at llxi for
isrr

oi

tIl

fh

o Sieml te ilot'u co s tofn h ttro
m

lii
tnclg n

1> htl
h

m

ixm \ (, h u e ,.tet 1 soil, iti

lseIa

a
i

lra

cr t

ali.sofs

TABLE 15.

EFFECT OF LIME ON FORAGE PRODUCTION OF CRIMSON

CLOVER

GROWN

ON COASTAL PLAINS SOILS

Average annual yield of forage per acre
Limestone added

per acre1

Site 12

Site 23

Site 34

Site 45

1944-45 dry forage Pounds 1,877 4,013 4,534 4,487 4,920 5.3

1952-53 dry forage Pounds 1,856 2,342

1948-50 green forage Pounds 11,940
-

1942-45 green forage Pounds 720 20,000 22,600

1946-48 green forage Pounds 0 1,600 10,200

Iw

Pounds 0 1,500 2,000 3,000 4,000 8,000 pH of unlimed soil

0 C -I P C
I-I

-12,940

6.5

5.5

5.7

5.7

4All plots received added phosphate and potash. 2 Norfolk sandy loam at Auburn which received borax in addition to other nutrients. 3 Kalmia fine sand on Henderson Brothers' Farm at Miller's Ferry. Norfolk loamy sand near Auburn. SLime applied in 1941 to Norfolk sandy loam at Auburn.

m

x

m

z

m

-I -I 0 Z

RESPONSE

of

CROPS

to

LIME

23

on Coastal Plains soils was increased several hundred pounds by a 1- or 2-ton per acre application of lime every few years, Table 12. The calcareous and neutral soils of the Black Belt area do not require added lime for good white clover production, whereas results from a number of experiments on the acid clay soils of that area have shown a definite need for moderate to heavy lime applications, Table 13. Lime was particularly necessary for maintaining legume stands. Observations are convincing evidence that the continued greater production of limed pastures is due, to a large extent, to the more abundant growth of clover. Increased forage production of a white clover-grass mixture at two separate locations in the Piedmont area was obtained from the application of 1 ton of lime, Table 14. The necessity of maintaining an adequate supply of lime for crimson clover has been shown by results of several experiments, Tables 15 and 16. Lime can mean the difference between a crop failure and a good crop, Table 15-site 4.
TABLE 16. EFFECT OF LIME ON FORAGE PRODUCTION OF CRIMSON CLOVER, 1947-49

Limestone added 1 per acre Pounds 0 4,000 pH of unlimed soil

Average annual yield of green forage per acre Hartsells very fine sandy loam Pounds 5,680 12,300 5.1 Lloyd sandy clay loam Pounds 12,120 20,020 5.8

All plots received adequate phosphate, potash, boron, zinc, and manganese.

Adequate soil lime not only greatly influences the production of clover forage, but it also affects seed production. However, it is pointed out that adequate soil boron is also essential for the benefits from liming to be realized in clover seed production. The yield of crimson clover seed was markedly increased on Norfolk sandy loam by an application of lime when the soil received an application of borax, Table 17. Much of the South's leguminous pasture in the past has resulted from the tolerance that lespedeza has toward soil acid. However, the need for lime by lespedeza may be considered in much the same light as clover, keeping in mind its greater tolerance for soil acidity. Results of experiments with lespedeza show that forage yields increase considerably from liming an acid soil,

24

ALABAMA

AGRICULTURAL

EXPERIMENT

STATION

TABLE 17. EFFECT OF LIME ON PRODUCT-ON OF CRIMSON CLOVER SEED NORFOLK SANDY LOAM RECEIVING BORAX APPLICATIONS, MAIN STATION

ON

Limestone added
per acre

Average annual yield of seed per acre Site 1 Site 2

1942-48 Pounds 232 433

1954
Pounds

Pounds 0 1,500 2,000 3,000 4,000 8,000
pH of unlimed soil

599 1,170

482
552 696 5.3 1,132 995 5.0

TABLE 18.

EFFECT OF LIME ON PRODUCTION OF ANNUAL LESPEDEZA AND SERICEA

IN 1945 Yield per acre
Limper acre 1 Sericea 2 dry hay dry hay Annual lespedeza 2 Dry hay Seed Annual lespedeza dry hay

Pounds 0 1,000 1,500

Pounds 1,983 2,692

Pounds 671 2,223 2,648 2,984 3,005

Pounds 110 350 ..

Pounds 1,982 1,544 2,554 2,363 2,325

2,000
3,000 4,000 5,000 7,000 8,000
pH of unlimed soil
'Adequate
2

372
507 533

5.3

phosphate and potash supplied to all soils. Norfolk sandy loam at Auburn. SDickson silt loam in Limestone County.

TABLE

19. Cow DAYS OF GRAZING AND WEIGHT GAINS OF BEEF CATTLE CLOVER-GRASS PASTURES ON EUTAW CLAY, LIMED AT 2- AND 4-TON RATES, BLACK BELT SUBSTATION, 1946-481

ON

Limestone added per acre

2

Average annual grazing

Average annual beef gains per acre

Pounds 0 4,000 8,000

Cow days per acre 174 205 205

Pounds 272 314 315

1 Pasture mixture included white clover, Persian clover, lappacea clover, lespedeza, and Dallisgrass. 2 Adequate phosphate added to each plot.

RESPONSE

of

CROPS

to

LIME

25

Table 18. Not only has forage production increased by liming the soil, but seed yield of lespedeza also increased. The ultimate purpose of greater forage production is greater animal production. It was found at the Black Belt Substation that limed soil growing a pasture mixture provided beef cattle grazing for a longer time and produced greater beef weight gains than pasture on unlimed soil, Table 19.
SOIL IMPROVING LEGUMES - WINTER AND SUMMER

(Vetch, Austrian Winter Peas, Soybeans, Alyce Clover, Crotalaria) Farmers have observed, and there is abundant supporting experimental evidence, that most of their fields produced more when legumes were grown in the crop rotation. One of the most important uses of lime is in promoting legume growth. In general, yields of legumes grown on acid soils are increased by the application of lime, and many of the failures with these crops may be caused by the lack of lime. The practice of interplanting summer legumes with corn has decreased considerably in recent years. The more common practice now is the use of a winter cover crop in the rotation. Legumes grown in rotation with other crops on acid soils will consistently produce more organic material where lime has been
TABLE 20. EFFECT OF RATES A OF LIME AND APPLICATION 2-YEAR ROTATION METHOD ON WEIGHT OF CORN VETCH PRODUCED IN WITH COTTON AND

AT VARIOUS

LOCATIONS,

1931-50

Limestone applied, rate per acre, and method1 None Drilled every 2 years 200 pounds 400 pounds 600 pounds Broadcast every 10 years 1,000 pounds 2,000 pounds 3,000 pounds pH of unlimed soil in 1946
1

Average annual weight of green vetch per acre Prattville' Headland' Crossville' Belle Mina Pounds 10,822 11,430 13,249 12,990 18,067 13,867 12,721 5.6 Pounds 6,863 9,437 9,445 9,356 10,040 9,783 9,526 5.4 Pounds 4,485 6,981 7,670 7,795 7,145 8,174 8,169 5.0 Pounds 9,776 10,616 11,247 11,264 10,463 11,580 11,851 5.4

Complete fertilizer added to cotton in the rotation. SGreenville sandy clay loam. SNorfolk sandy loam. SHartsells fine sandy loam. ' Decatur clay loam.

TABLE 21. EFFECT OF LIMESTONE ON WEIGHT OF VETCH PRODUCED IN A 2-YEAR ROTATION WITH COTTON AND CORN AT VARIOUS SITES DURING A 25-YEAR PERIOD

0I

Treatment'

Aliceville 2 Kalmia s.l.

Average annual weight of green vetch per acre Coastal Plains soils Crossville' Brewton' Monroeville 4 Prattville 4 Headland' Kalmia s.l. Magnolias.l. GCeenville s.c.l Norfolk s.l. Hartsells f.s.l.

Limestone Valley soils Alexandria 4 Belle Mina' Decatur cl. Decatur cl.
c-

1930-48
Unlimed Limed

Pounds
11,609 11,829

Pounds
6,839 10,272

Pounds
11,658 14,141

Pounds
12,949 12,545 21,625 20,358 5.9

Pounds
10,561 12,224 4,644 3,387 5.8

Pounds
9,356 11,613 13,519 18,352 5.6

Pounds
10,105 10,698 14,758 15,129 6.0

Pounds 11,774
13,276 16,852 17,478 6.0'

M

1949-55 15,098 Uniimed 15,575 11,067 16,962 Limed 15,542 15,527 pH1 of unlimed soil 6.3 5.8 5.6 in 1946 1Cotton received a complete fertilizer in the rotation. 2 One ton of lime each in 1929 and 1954.
2One

0
m m z-

'Two

ton of lime each in 1929, 1939, and 1954. tons of lime in 1929 and 1 ton in 1954.

One ton of lime each in

1929, 1933, and 1954.

OI Z

M

z
m
TABLE 22. EFFECT OF RATES OF LIME AND APPLICATION METHOD ON WEIGHT OF SOYBEANS AND CROTALARIA INTERPLANTED WITH CORN IN A 2-YEAR ROTATION OF COTTON-VETCH-CORN AT SEVERAL LOCATIONS
0

0

n

Limestone applied, rate per acre, and
method'

Prattville' Soybeans 1931-34 Crotalaria 1937-45

Average annual;green weight of plants per acre Headland' Crossville4 Crotalaria 1938-40 Soybeans 1930-34
Crotalaria

0

1936-45

'Soybeans
7,828 7,979 8,465 7,328 8,326 8,775

Belle Mina'
Crotalaria

-o
0

1930-45

1937-45

None
Drilled every 2 years

Pounds 7,345 7,787
8,431 8,575

Pounds 2,383 2,852
3,444 3,114

Pounds 2,004 1,801
2,374 2,185

Pounds 3,948 4,142
5,216 5,349

Pounds 2,026 1,917 2,235 2,174 2,092 1,958 2,294
5.0

Pounds 7,414

Pounds 2,778 2,705
3,127

m

200 pounds
400 pounds 600 pounds Broadcast every 10 years

3,233 2,896 3,220 3,125
5.4

1,000 pounds 2,000 pounds 3,000 pounds
pH of unlimed soil in 1946
1

8,478 8,408 9,061
5.6

3,229 3,137 2,877

2,047 2,301 2,454
5.4

4,815 5,388 5,858

600 pounds per acre of 6-8-4 added to cotton in the rotation.
sandy loam.

'Nrfl

2Greenville sandy clay loam. Hartsells fine sandy loam.
Decatur clay loam.

N%

28

ALABAMA

AGRICULTURAL

EXPERIMENT

STATION

added. Results of experiments at several locations throughout the State have shown that vetch growth was increased by liming,
Tables 20, 21, and 24. Growth of Austrian winter peas was almost

doubled by liming in a test at Brewton, Table 23. Similarly, yields of summer legumes grown on acid soil were increased. Lime has been highly beneficial to soybeans, crotalaria, and Alyce clover grown on acid soils, Tables 22, 23, and 24. Crotalaria is probably the least responsive to liming, while Alyce clover is the most responsive.
TABLE 28. EFFECT OF LIME ON WEIGHT OF AUSTRIAN WINTER PEAS AND CROTAA 2-YEAR ROTATION WITH COTTON AND CORN ON KALMIA SANDY LOAM, BREWTON EXPERIMENT FIELD, 1984-44

LARIA GROWN IN

Grade of fertilizer added 1 to cotton in rotation Grade 6-0-4 6-0-4 6-5-4 6-5-4 6-10-4 6-10-4 6-10-4 6-15-4 6-15-4
SApplied

Kind of lime and per-acre rate of application every 6 years

Average annual green weight per acre Austrian winter peas Pounds 2,208 3,225 3,629 6,980 4,836 8,368 8,234 5,601 8,595 Crotalaria Pounds 7,131 7,256 7,488 7,830 6,858 7,773 6,548 5,794 6,626

None 2,000 pounds dolomite None 2,000 pounds dolomite None 2,000 pounds dolomite 2,250 pounds basic slag None 2,250 pounds basic slag

at rate of 600 pouInds per acre.

TABLE

24.

EFFECT OF LIME ON PRODUCTION OF ALYCE CLOVER, VETCH, SOYBEANS, ON NORFOLK SANDY LOAM, MAIN STATION

AND

Limestone added per acre Pounds 0 1,500 3,000 4,000 8.000 pH of unlimed soil

Average annual weight of plants per acre Vetch Soybeans Alyce clover green matter dry matter dry matter 1942-48 1942-44 1945 Pounds 383 2,843 5,285 4,952 4,646 5.3 Pounds 2,619 5,037 4,899 5,545 4,730 5.3 Pounds 3,402 9,004 10,808

5.4

RESPONSE

of CROPS to LIME

29

(;I 1.SSI"S

rim

ci~ :thoot ,

.5.5

to

7.(,. (rse ;l
fo001
2,O\

re' iii

oll\ r

a
l'

mllI(Irate 'OiI)1)1

of ,oil (Acliii for

tI.

13cin I(Sld

is Ns

1 roliril

tie

mos

to Jl

iian t l

t

f t

iirt ,ics siiili fo a

i. 1i

l

iii'er Ii

if i

s

li2.

dru itN

l

d(itNt Ainlii

trc f

d ta

i

if~ti II'I

Aii

t 2hatiii'

reI cNN

1)1

40s( t
scars

XXtest crop

Tit I

Iie Nt?: i
X ;IN Ir

( 1) ceit ((
at

rIl til(( of te l d 2 o

1im(N(r added 1
so ls e

almstil

aIIill(

\iki

FIGURE 5. Oats on a very acid Norfolk sandy loom at Wiregrass Substation, Headland, show effect of lime. Left-soil pH is 5.6; right-soil pH is 4.0.

Ow

TABLE 25.

EFFECT OF LIME ON THE YIELD OF SWEET SORGHUM AND OATS IN ROTATION ON NORFOLK SANDY LOAM ACID BY CONTINUOUS USE OF AMMONIUM SULFATE FERTILIZER SINCE 1911, MAIN STATION

MADE VERY

Limestone added per acre' 1936-39 Pounds

Sweet sorghum stover per acre 1940-43

Average annual yield of crop by periods Oats grain per acre 1936-39 1940-43 Bu. 12.1 28.1 30.1 16.5 24.7 25.5 24.9 1944-46 Bu. 6.5 18.2 19.8 6.2 12.0 16.5 18.8 1947-50 Bu. 8.9 30.8 34.5 32.2 34.9 36.5 39.4 1951-53 Bu. 8.6 36.7 48.2 39.7 39.6 87.2 40.5

Soil pH in 1953

1944-45

a
A
F

Lb. Lb. Lb. Bu. 516 457 101 15.4 None 4,408 3,756 1,813 27.2 210 annually 420 annually 4,871 7,145 5,631 33.0 1,144 in 1934 and 19472 3,652 560 78 25.9 7,326 2,198 84 34.7 2,608 in 1934 and 19472 8,444 7,051 162 31.2 4,072 in 1934 and 19472 9,143 9,163 2,849 86.6 5,536 in 1934 and 1947'2 SA complete fertilizer was added each year. Only one treatment was applied in the case of the sweet sorghum.

a

4.3 4.7 5.5 4.7 5.2 5.8 6.4

r-

c

C
-1

C
'Ii

2

x
x m

m

z -I -o H -I
0

z

RESPONSE

of CROPS

to LIME

1)\guts

(il

an acidl soil. Oat viclds~ \\ cl( adln(jat( liik it
X

IitVras((l 1iXat -16.

least 50( x tI
from

lcr ((I it xxllcr(

s

applli(d, Jl Il

The Iin nee oft~ LiaiI (I -l4In i IIst he 0( if I? IQ is to h1 ob(itain ed. Increasedl Niclds of "riti sm 501 iii

t(,(l(
('sIii

lt
foi

Ta hlt 27T
1riuill

Simijlar resMIts
stm\ cI

hax

ei

loui

ohtaii

(d at

\tihu)r1

lhold,

ani

1

icits,

TIahl(

-17.

I'm ct'

iid

da

/~

uui .

(d oii'tIn

Ix ce

A

linlu

\('1
1.
io

1.22
1 5.S I.W (0
IS-1 an 't (pa ,ann
i;

IU11(5 5-0 I
ul n i~ t c tl/ ra

L(A
I 1,11allS

a (di 5u d

d d

;

t.5

FIGURE 6. Effect of lime on groin sorghum growing on Norfolk sandy loom at Wiregross Substation, Headland. Left-lime applied; right-unlimed.

32

ALABAMA

AGRICULTURAL

EXPERIMENT

STATION

TABLE 27. EFFECT OF LIME ON YIELD OF GRAIN SORGHUM ON ACID SOILS AT WIDELY SEPARATED LOCATIONS

Two

Average annual yield per acre Limestone added
per acre Site2

Site 2' Grain Bushels 55.6 Stover Tons 5.40

grain Pounds None 1,000 Bushels 37.2 34.4

2,000 3,000

45.2
45.2 46.4

71.1
65.6 61.9 5.0

6.63
6.82 7.06

4,000 5,000 7,000 8,000 pH of unlimed soil
1A 2

complete fertilizer was applied to all plots. Dickson silt loam in Limestone County in 1945. ' Norfolk sandy loam at Auburn in 1954.

Johnsongrass on unlimed acid soil was almost a complete failure at Auburn. Liming the soil increased yields several-fold, Table 28. A lime application on an acid Black Belt soil gave a 3-fold increase in hay production, Table 28. Sudangrass is similar to Johnsongrass in its need for lime. Its growth on very acid soils is considerably increased by liming, Table 28.
TABLE 28. EFFECT OF LIME ON HAY PRODUCTION
GRASS

OF JOHNSONGRASS

AND

SUDAN-

Limestone added per acre 1 Pounds None 1,500 3,000 4,000 6,000 8,000 pH of unlimed soil
1

Annual yield of dry hay per acre Johnsongrass Sudangrass 1945 1942-46 Site 12 Site 2' Site 32 Pounds 106 3,284 3,846 4,001 4,048 4.7 5.7 Pounds 1,696 Pounds 2,150 7,460 9,500

4,868

A complete fertilizer was added to all plots. 2 Norfolk sandy loam at Auburn. 3Vaiden clay loam at Browns.

RESPONSE

of

CROPS

to

LIME

33 AND

ALFALFA, SWEET CLOVER,

CALEY PEAS

Alfalfa and sweet clover have a high requirement for soil calcium. The lime requirement of Caley peas is also high but may be somewhat less than that for alfalfa and sweet clover. All three plants thrive in a soil that has sufficient calcium for a soil pH range of 6.5 to 7.5. Crop failures may result if very much soil acid is permitted to develop in soils devoted to growing these crops. The pH of most Alabama soils is too low to maintain production of these crops without heavy lime applications. An abundance of soil calcium is also vital for maintenance of stand over several years. Sufficient soil calcium may be present for the first year's growth of alfalfa, but the stand will become progressively poorer each year, unless adequate lime is present or supplied. Alfalfa was first grown successfully in Alabama on the neutral and calcareous soils of the Black Belt. These are the only soils in the State that still have sufficient native lime to support and maintain satisfactory alfalfa growth. Probably every other soil in the State will require lime applications to maintain a satisfactory growth of alfalfa, sweet clover, and Caley peas. Unlimed Coastal Plains soils will produce practically no alfalfa hay, but satisfactory yields are produced when these soils are limed, Tables 29 and 30. The neutral and calcareous soils of the Black Belt need no additional lime for good growth of these three crops. However, the acid soils of that area need heavy applications of lime for good growth of Caley peas, Table 31. Complete crop failures may result on unlimed acid Black Belt soils, Table 31. Sand Mountain soils are much too low in soil lime to grow alfalfa, sweet clover, and Caley peas unless lime is added, Tables 29 and 30. The Limestone Valley soils are higher in soil lime than many other Alabama soils. Still, alfalfa yields have been doubled there by liming, Table 32. The yield of alfalfa on Piedmont soils was greatly increased by a lime application. Production on unlimed soil was practically a failure, Table 29.

iw.

TABLE 29. EFFECT OF LIME ON HAY YIELD OF ALFALFA ON SOILS OF THE COASTAL PLAINS, SAND MOUNTAIN, AND PIEDMONT AREAS DURING A 2- TO 3-YEAR PERIOD

Limestone added
per acre'

Coastal Plains soil
Site 12 Site 2'

Average annual yield of dry hay per acre Sand Mountain soil
Site 34 Site 45

Piedmont soil
Site 56 Site 6'

>

1943-45

1947-49

1943-45 Pounds 4,225 4,917

1947-49 Pounds 352 6,617

1944-45 Pounds 6,465 6,539 6,553

1947-49 Pounds 881 5,353

Pounds Pounds Pounds 0 426 1,352 6,742 2,000 4,000 9,569 6,403 7,484.. 8,000 pH of unlimed plots 5.5 1 All plots received phosphate and potash. 2Norfolk sand at Auburn. SNorfolk loamy sand at Auburn. SHartsells fine sandy loam at Crossville. 5 Hartsells fine sandy loam at Boaz. 6 Madison clay loam at Auburn. SLloyd sandy clay loam at Camp Hill.

F
c 0

5.1

5.8

I-

o

0
m **I
c

z
-I

z

m 0 H

z
Wo
0 TABLE 80. EFFECT OF LIME ON YIELD OF ALFALFA HAY ON VARIOUS ACID SOILS IN THE STATE

Average annual yield of hay per acre Limestone added
per acre

0 Limestone Valley soil Alexandria 7 5-yr. av. Pounds 6,896 6,788 6,355 Piedmont soil Auburn' 4-yr. av. Pounds 7,041 8,584 8,283 Camp HilP 4-yr. av. Pounds 5,216 5,559 5,546
9 0
Im

Coastal Plains soil Prattville 4-yr. av.
1

Winfield 6-yr. av. Pounds 5,367 6,609 7,432

Atmore 5-yr. av. Pounds 6,600 7,658 8,555 8,738

3

Fairhope 3-yr. av. Pounds 8,143 7,712 7,695 8,310

Tuskegee 4-yr. av. Pounds 4,048 4,371 5,201

Sand Mt. soil Crossville6 4-yr. av. Pounds 7,806 8,473 6,815

Pounds 2,000 4,000 6,000 8,000 16,000

Pounds 6,137 9,287 8,419

1 Greenville fine sandy loam. Atwood fine sandy loam. fine sandy loam. Norfolk sandy loam. 6 Susquehanna fine sandy loam. 6 Hartsells fine sandy loam. SDecatur clay loam. S Madison clay loam. SLloyd clay loam.

'Orangeburg

w

TABLE 31.

EFFECT OF LIME ON HAY YIELD OF CALEY PEAS GROWN ON ACID SOILS OF THE BLACK BELT AREA

Limestone added
per acre

Site 12
1944-45

Site 23
1945

Site 34
1945

Yield of hay per acre Site 45
1944-45

Site 5"
1945

Site 64
1945

Site 74
1945

green wt.

green wt.

green wt. Pounds 419 5,157 6,551 5.2

green wt. Pounds 0 4,502 8,702 4.7

dry wt. Pounds 396 3,105 4.7

green wt. Pounds 746 5,550 6,586 4.6

green wt. Pounds 11,250 17,500 4.5 r
C
c-

Pounds Pounds Pounds 1,725 0 2,267 8,202 3,000 19,470 4,000 8,810 6,000 14,160 8,000 5.3 pH of unlimed soi 'Phosphate and potash added to all plots. 2Flint sandy loam at Tuskegee.

C

'4Vaiden clay at Marion Junction. Eutaw
clay at Marion Junction

sVaiden clay loam at Browns.

m

z

RESPONSE of CROPS to LIME
TABLE 32. EFFECT OF LIME ON YIELD OF ALFALFA ON
VALLEY SUBSTATION

37
DECATUR CLAY LOAM,

TENNESSEE

Limestone added Limestone per acre Pounds 0 3,000 6,000 12,000

Average annual yield of dry hay per acre Second planting First planting 1931-36 193741 Pounds 2,363 3,317 3,852 .. Punds 2,723 4,701 5,700 6,637

PEANUTS Commercial peanut production in the State is centered on the sandy Coastal Plains soils of southeastern Alabama. Because of the nature of sandy soils, high rainfall leaches the soil minerals and prevents the soil from storing large reserves of plant nutrients. The soil's supply of potassium, certain minor elements (e.g., zinc), and the liming nutrients of calcium and magnesium are rapidly removed from Alabama's peanut producing soils.
PEANUT SOILS ARE RAPIDLY EXHAUSTED

The rapid loss of soil minerals to the peanut plant and to leaching water is soon reflected in sharp reductions in yield. On a test area at the Wiregrass Substation, peanuts were grown continu-

ously from 1932 to 1949 without fertilizer or lime. The soil was yielding about 1 ton of dry peanuts per acre in 1932; by 1949, the yield was 360 pounds or less, Tables 33 and 34.
TABLE 33. EFFECT OF LIME, GYPSUM, AND FERTILIZERS ON YIELD OF RUNNER PEANUTS IN 1949-50 AFTER CONTINUOUS CROPPING OF PEANUTS SINCE 1932 ON UNFERTILIZED AND UNLIMED NORFOLK SANDY LOAM, WIREGRASS SUBSTATION

Kind and amount of fertilizer added per acre' None 200 pounds 400 pounds 200 pounds 400 pounds 200 pounds 400 pounds 200 pounds

Calcium material per acre' None None None 500 pounds gypsum 2,000 pounds limestone

Average annual yield of nuts per acre Pounds 360 796 895 1,857 1,942

muriate of potash superphosphate muriate of potash superphosphate muriate of potash superphosphate muriate of potash

'Fertilizer included the minor nutrients of boron, zinc, copper, and manganese. 2 Liming material included 100 pounds per acre of magnesium sulfate.

38

ALABAMA AGRICULTURAL EXPERIMENT

STATION

TABLE 34. EFFECT OF LIME AND FERTILIZER ADDED IN 1950 ON YIELD OF RUNNER
PEANUTS GROWN CONTINUOUSLY LOAM SINCE ON UNFERTILIZED 1932, WIREGRASS AND UNLIMED SUBSTATION NORFOLK SANDY

Fertilizer added per acre

Minor nutrients 1 added

Limestone added
2

1950 yield of dry peanuts per acre

per acre

None None None 400 200 400 200
1

No No Yes superphosphate muriate of potash superphosphate muriate of potash No Yes

Pounds None 2,000 2,000 2,000 2,000

Pounds 109 762 774 1,948 2,048

pounds pounds pounds pounds

Minor nutrients consisted of 5 pounds borax, 10 pounds zinc sulfate, 10 pounds

copper sulfate, and 30 pounds manganese sulfate per acre. 2 Lime included 100 pounds per acre of magnesium sulfate. RESTORING EXHAUSTED PEANUT SOILS

Adding needed plant nutrients can restore an exhausted soil to its potential capacity for producing peanuts. Peanut yields from depleted soil at the Wiregrass Substation were immediately restored to about 1 ton of nuts per acre by an application of phosphorus, potassium, calcium, magnesium, and minor elements, Tables 33 and 34. The necessity for calcium and magnesium is clearly demonstrated by the 1,000-pound yield increase obtained from either gypsum or lime along with magnesium sulfate, Table 33. The potential benefit from lime is not realized unless all other plant nutrients are adequately supplied, Table 34. The peanut yield on an unfertilized and unlimed soil at the Wiregrass Substation was 109 pounds of nuts per acre. An application of lime raised the yield to 762 pounds per acre. However, when other needed plant nutrients were added along with lime, the peanut yield increased to about 1 ton per acre.
ALABAMA'S PEANUT SOILS NEED LIME

The need for lime on Alabama soils devoted to growing peanuts was shown by this Station almost 50 years ago. Results from early experiments showed that most, but not all, limed peanut soils produced more than did unlimed soils. Although the majority of past experiments proved the need for lime, the effort to obtain a clear-cut picture of lime requirements

RESPONSE

of

CROPS

to

LIME

39

of peanuts was frustrated by numerous experiments in which lime had no effect on peanut yields, or caused serious reduction in yield. Based on the adage that "if a little is good, more is better," some peanut fields may have received too much lime at one application. For example, one field received sufficient lime to raise the soil pH to about 7.5. This field in 1950 produced only 63 pounds of peanuts per acre, Table 35. An application of potash brought the yield up to about 700 pounds. When zinc was applied in addition to potash, the yield was increased to about 1,400 pounds of nuts. A yield of 1,800 pounds was obtained when potash and four minor elements were applied to the heavily limed soil. It is not enough to supply lime to an unfertilized soil in the peanut-growing area. Not only has the calcium and magnesium supply been greatly reduced but likewise the soil's supply of other nutrients, such as potassium, zinc, and boron. When the possible inadequacy of these other nutrients is overlooked, "over-liming" injury can result. The yield of peanuts was reduced by moderate
TABLE 35. EFFECT OF ZINC AND OTHER MINOR NUTRIENTS ON YIELD OF RUNNER

PEANUTS IN 1950 GROWN ON A SOIL THAT HAD BEEN PREVIOUSLY "OVER-LIMED" TO A SOIL PH OF ABOUT 7.5

Fertilizer

Minor nutrients

Yield of dry nuts

Percentage of sound

added None Potash Potash Potash '5 pounds borax, 5

added None None Zinc AlP

per acre Pounds 63 714 1,390 1,804

mature kernels Per cent 49.9 64.9 68.1 70.5

pounds copper sulfate, 15 pounds zinc sulfate, and 25

pounds manganese sulfate per acre.
TABLE 36. EFFECT OF RATE OF LIME AND METHOD OF APPLICATION ON YIELD OF
PEANUTS GROWN IN A 2-YEAR ROTATION WITH COTTON AND VETCH,

NORFOLK SANDY

LOAM,

WIREGRASS SUBSTATION,

1941-49

Limestone added peracre' per

Frequency of application

Method of application

Av. annual yield of dry peanuts per acre

Soil pH in 1940

Pounds 0 200 400 600 1,000 2,000
3,000

Every year Every year Every year Every 10 years Every 10 years
Every 10 years

Drilled Drilled Drilled Broadcast Broadcast
Broadcast

Pounds 1,820 1,872 1,814 1,494 1,886 1,507
1,416

5.4 5.7 5.8 6.0 5.6 5.7
5.7

S600 pounds per acre of 0-8-4 applied to cotton in the rotation.

40

ALABAMA

AGRICULTURAL

EXPERIMENT

STATION

rates of lime at the Wiregrass Substation where only a small amount of potash fertilizer was applied to cotton in the rotation, Table 36. Frequent small applications of lime slightly increased the peanut yields. In another experiment at the Wiregrass Substation where higher rates of fertilizer were used, there was an average yield increase of about 350 pounds per acre when 1 ton of lime was applied, Table 37. A comparison between these two effects of lime illustrates the necessity of satisfying all needs of the plant.
TABLE 37. EFFECT OF LIME ON PEANUT YIELDS GROWN IN A 3-YEAR ROTATION OF CORN-PEANUTS HOGGED-GREEN MANURE OATS-PEANUTS ON NORFOLK SANDY LOAM, WIREGRASS SUBSTATION, 1942-51

Limestone added per acre'

Av. annual yield of dry peanuts per acre

Pounds None 2,000 in 1942
1

Pounds 1,822 1,587

300 pounds per acre of 0-8-12 was applied to peanuts.

UNDERSTANDING

THE PEANUT-SOIL

LIME PROBLEM

Many agricultural problems in the past can be explained in the light of present-day knowledge. Inadequate potash fertilization was responsible for some failures of peanuts to benefit from liming. No doubt, other failures have resulted from an insufficient supply of soil zinc or other minor nutrients. Although the response of peanuts to liming had consistently pointed out the need for lime, there were always some results that defied simple explanations. The problem has been attacked on a broad scale during the last 12 years. Almost 100 experiments have been conducted on farmers' fields to better ascertain their lime needs and to gain insight into the problem of lime and peanuts in Alabama. No concerted effort was made to eliminate all instances of "over-liming," but it was avoided as much as possible by using light applications of lime. In view of this, some erratic results were to be expected.
SOIL LIME AND PEANUT YIELDS

Results from numerous field tests established a definite relationship between the soil's supply of lime and the effect of a lime application on peanut yields, Table 38. If the soil's supply of lime was above 700 to 800 pounds per acre, there was little chance of

RESPONSE

of

CROPS

to

LIME

41

TABLE 38. EFFECT OF LIME AND GYPSUM ON YIELD OF RUNNER PEANUTS GROWN ON SOILS WITH DIFFERENT AMOUNTS OF NATIVE LIME AT NUMEROUS

LOCATIONS IN SOUTHEASTERN ALABAMA, 1943-54 Average Limestone added to soil per

Native supply Tests Average per Native lime suppl acre yield
of soil lime Tests

Yield increases
per acre Most Least

Tests affecting
yield Increase Decrease

of unlimed soil per acre Average

<

Lb. 450 450-549 550-649 650-749 750-899 900-1,299 > 1,299

No. 15 13 14 16 13 13 8

Lb. 1,182 1,233 1,204 1,568 1,297 1,530 1,441

Lb. Lb. No. No. 1 8 -85 600 2 554 -38 8 3 9 -166 373 6 8 -207 442 4 6 -200 165 7 6 377 -288 4 4 313 -233 Gypsum added to soil Tests affecting Yield increases per acre yield Least Increase Decrease Most Average Lb. 266 333 105 89 73 62 62 Lb. 447 649 395 653 221 286 386 Lb. 59 6 -467 :-110 -102 -158 -106 No. 12 11 8 6 8 7 4 No. 0 0 2 4 2 4 3

Lb. 322 217 82 74 22 14 18

<

450 450-549 550-649 650-749 750-899 900-1,299 > 1,299

15 13 14 16 13 13 8

1,182 1,233 1,204 1,568 1,297 1,530 1,441

receiving benefits from added lime. However, as the supply of soil calcium decreased below this level, the frequency and magnitude of yield increases brought about by liming became greater,

Table 38 and Figure 7. An abundant supply of calcium in the "pegging" zone appears to be essential for good peanut production. As a rule lime is used as the calcium carrier. However, gypsum (land plaster) has been successful in promoting better peanut yields, Table 88. The effect of gypsum dusted on peanuts at blooming time is similar to that from a broadcast application of lime, Table 38 and Figure 7. Gypsum applications will avoid cases of "over-liming" where an unfavorble pH would have resulted from the use of lime. However, the very acid soils may benefit more from lime than from gypsum because of the acid-neutralizing property of lime. In general, gypsum is only considered as a supplement to lime, since lime is needed occasionally to adjust the soil pH to a more favorable level.

42

42 ALABAMA AGRICULTURAL EXPERIMENT STATION

Yield
3501

increasefrom lime 0limegypsum - (2 tests) (71 tests)

250

2 00

150

1

00

0 50

-

A-----

0o
400 500 600 700 800 900 1000 1100 1200 1300 1400 Exchangeable Calcium 11b. per acre of calcium carbonate)

FIGURE 7. Effect of native soil lime on the response of runner peanuts to lime or gypsum.

SOIL PH AND PEANUT YIELDS

Since the soil pH reflects the lime status of a soil, there is a relationship between soil pH and the effect of lime on peanut yields, Table 39. The more acid a soil is, the greater is the probability of a yield increase from a lime or gypsum application. However, the, results obtained from using the pH values exclusively are quite erratic. The primary value of knowing the soil pH appears to be its usefulness in avoiding "over-liming." In determining lime needs of peanut soils, the soil pH and soil lime measurements supplement the usefulness of each other.

RESPONSE

of

CROPS

to

LIME

43

TABLE 39. EFFECT OF LIME AND GYPSUM ON YIELD OF RUNNER PEANUTS GROWN ON SOILS OF VARIOUS PH VALUES AT NUMEROUS LOCATIONS IN SOUTHEASTERN ALABAMA, 1948-54

1 ton of limestone per acre added

Soil pH range Tests

Av. per acre

yield of unlimed soil Lb. 1,212 1,104 1,425 1,219 1,845 1,383

Yield increases

Tests affecting Least Increase Decrease

per acre
Average Most

<

5.1 5.1-5.3 5.4-5.5 5.6-5.8 5.9-6.0 > 6.0

No. 14 15 15 15 12 15

Lb. 154 158 86 184 -5 10

Lb. 554 555 348 494 253 303
Yield increases

Lb. -41 -166 -288 -55 -207 -233

No. 10 9 6 9 4 8

No. 3 4 5 2 7 7

500 pounds of gypsum per acre added Tests affecting

per acre
Average Most Least

yield
Increase Decrease

<

5.1 5.1-5.3 5.4-5.5 5.6-5.8 5.9-6.0 > 6.0

14 15 15 15 12 15

1,212 1,104 1,425 1,219 1,845 1,383

Lb. 184 214 139 220 99 70

Lb. 543 653 649 676 189 388

Lb. -158 -94 -140 -110 -99 -467

No. 11 11 7 7 8 10

No. 2 1 4 2 1 4

PER CENT SOUND. MATURE KERNELS AND PEANUT YIELDS

The percentage of sound mature kernels (S.M.K.) determines the quality of nuts produced and their value. A number of factors, including soil conditions, determine the S.M.K. in the harvested crop. An unfavorable balance of soil nutrients will adversely affect S.M.K. values, Table 35. The S.M.K. value of peanuts produced on lime-deficient soil can be increased by liming. The increased S.M.K. values are reflected in the increased yields obtained. A low S.M.K. does not necessarily mean that the soil needs lime. On the other hand, if the harvested nuts have an S.M.K. value of about 65 or above, there is small likelihood that benefits will be

gained by liming, Table 40.

44
TABLE 40.

ALABAMA AGRICULTURAL EXPERIMENT STATION
EFFECT OF LIME AND GYPSUM ON THE YIELD OF RUNNER PEANUTS 1 WITH VARIOUS S.M.K. VALUES FROM UNLIMED SOIL AT NUMEROUS LOCATIONS, 1948-54

S.M.K.
from

1

unlimed soil Pct. < 55.0 55-59.9 60-64.9 65-69.9 > 69.9

Av. per acre Tests yield of unlimed soil
No.

1 ton of limestone per acre added Yield increases Tests affecting per acre yield Average Most Least Increase Decrease Lb. Lb. Lb. No. No. 1 -118 5 189 494 4 -288 7 206 555 5 -341 12 58 377 10 10 -494 -22 152 9 3 44 -269 -78 500 pounds of gypsum per acre added Tests affecting Yield increases yield per acre Most Least Increase Decrease Average Lb. 250 208 128 46 -46 Lb. 543 653 649 813 221 Lb. -102 -78 -286 -328 -467 No. 16 11 15 12 6 No. 1 3 5 7 6

17 15 21 20 12

Lb. 977 1,157 1,298 1,526 1,562

<

55.0 55-59.9 60-64.9 65-69.9 > 69.9
1

17 15 21 20 12

977 1,157 1,298 1,526 1,562

S.M.K. means per cent sound mature kernels.

SOYBEANS FOR OIL

The soybean plant is capable of producing good yields over a rather wide pH range of about 5.5 to 7.0. It is considered to be a heavy feeder on calcium; in addition it is capable of obtaining adequate calcium from moderately acid soils. In Alabama, soybeans are decreasing in importance as a hay and green manure crop, but are becoming increasingly more important as an oil crop. It is a plant with wide climatic adaptations that can be grown throughout the State. Since soybeans feed heavily on calcium, they will soon deplete the lime supply of soils poorly supplied with lime. Adequate testing throughout the State to determine lime requirement of soybeans has not been carried out. However, an experiment at Auburn gives an insight into the possible lime needs of soybeans. In 1955, unlimed soil with a pH of 4.8 yielded only 14.6 bushels of soybeans per acre. Liming the soil to a pH of 4.8 brought the yield to 20.0. When limed to a pH of 5.9 the yield was 80.8 bushels per acre of soybeans, Table 41.

RESPONSE

of

CROPS

to

LIME

45
ON VERY ACID NORFOLK

TABLE 41.

EFFECT OF LIME ON YIELD OF SOYBEANS
SANDY LOAM, MAIN STATION

1946

Limestone added per acre' 1955 1952 Pounds None 1,000 2,000 Pounds None 250 1,000

Yield of soybeans per acre in 19552 Bushels 14.6 20.0 30.3

Soil pH in 1955 4.3 4.8 5.9

Pounds None 2,000 4,000
1 The 2 The

soil was adequately fertilized. area was planted to peanuts until 1955.

No definite conclusion can be drawn from these limited data. However, there are good indications that the soil's lime supply will play an important role in greater soybean production. RECOMMENDATIONS The variable amounts of soil acidity and the efficiency of different liming materials make a hard and fast rule for liming impossible. The amount of lime needed to neutralize soil acidity depends upon (1) soil pH, (2) clay content, (3) type of clay, (4) organic matter content, (5) crop, and (6) kind and fineness of liming material. Using a soil test is the only reliable method of ascertaining lime needs. The soil test shows degree of acidity and amount of lime needed to neutralize that acidity. The Soil Testing Laboratory at the Agricultural Experiment Station of the Alabama Polytechnic Institute analyzed 19,187 soil samples by the end of 1955, Table 42. Of these samples, 34 per cent had a pH of 5.5 or less and needed lime for even the more acid-tolerant crops, such as cotton, corn, and oats. Approximately 74 per cent of the samples showed need for lime for legumes (pH
TABLE 42. SOIL PH VALUES FOUND BY THE SOILS TESTING LABORATORY AREAS, 1953-1955 BY SOIL

Soil area

Number of samples Number 2,471 2,109 567 1,325 651 12,064 19.187

Less than 5.0 Per cent 2.1 1.2 6.3 0.6 2.0 2.4 2.2

Soil pH 5.0-5.5 5.6-6.0 Per cent 32.3 38.5 44.8 22.1 16.6 32.5 32.2 Per cent 32.0 40.3 24.7 39.2 13.5 43.0 39.5

More than 6.0 Per cent 33.6 20.0 24.2 38.1 67.9 22.1 26.1

Limestone Valleys Sand Mountain Highland Rim Piedmont Black Belt Coastal Plains State average

46

ALABAMA

AGRICULTURAL

EXPERIMENT

STATION

6 or less). Thus, it can be concluded that a large portion of the agricultural land in Alabama to some degree suffers from inadequate lime. Lime is not a soil amendment that should be added annually. Lime needs of most crops on an acid sandy soil will be satisfied by a 1-ton application every 5 to 6 years. An acid clay soil will need 2 to 3 tons of lime every 7 to 8 years. An exact recommendation of amounts at specified intervals is impractical because of variation in farmland management. The most commonly used liming materials are given in Table 1, along with the relative neutralizing value of each. For greatest benefit to be realized from these materials, the degree of fineness is important. The finer the material, the more soil comes in contact with the lime particles and the more benefit is realized immediately. Coarse particles of lime are ineffective in neutralizing soil acidity. A liming material used should be of sufficient fineness so that 90 per cent passes through a 10-mesh sieve and 50 per cent through a 60-mesh sieve. In addition to neutralizing soil acidity, the liming material is an important carrier of plant nutrients. All liming materials contain calcium. Certain liming materials also contain other nutrients; for example, basic slag contains phosphorus, flue dust (lime-ox) contains potassium, and dolomite contains magnesium. Where magnesium is not included in the fertilizer program, dolomitic lime is desirable because it supplies calcium and magnesium and corrects soil acidity as well.