Soil Testing Guide for Home Gardening in Alabama

8/14/2019 Soil Testing Guide for Home Gardening in Alabama

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A Guide to Soil Testing and Fertilizer Recommendation for Home

Gardeners in Alabama

Leonard Githinji, Ph.D.

Assistant Professor / Extension Horticulture Specialist, Tuskegee University

Cooperative Extension Program, Tuskegee, Alabama

Chapter 1: Introduction

The goal of this soil testing and fertilizer recommendation guide is to provide

home gardeners and Extension agents with the necessary tools for better understanding

and interpretation of soil test reports. This is necessary to more accurately determine

fertilizer rates and any need for soil amendments, such as compost. The data in these

reports are only worthwhile if the tested soil sample accurately represents the sampled

garden; therefore, a summary of sampling methods is provided.

Efficient use of fertilizers is a major factor to consider in any program designed to

bring about maximum profits for producers, lower cost for consumers and enhance

environmental protection. Home gardeners tend to use increasing quantities of fertilizers

in a bid to increase yields to the desired levels. However, the amounts and kinds of

fertilizers required for the same crop vary from soil to soil, and even field to field on the

same soil. The use of fertilizers without first testing the soil is like taking medicine

without first consulting a physician to find out what is needed.

It has been documented by many scientists that fertilizers increase yields and

many home gardeners seem to be aware of this. However, applying the right kind of

fertilizer and the right quantity needed, and at the right time to ensure maximum profit is

the real problem. Without a fertilizer recommendation based upon a soil test, a gardener

may be applying too much of a little needed plant food element and too little of another

element which is actually the principal factor limiting plant growth. This not only means

an uneconomical use of fertilizers, but in some cases crop yields actually may be reduced

because of use of the wrong kinds or amounts, or improper use of fertilizers.


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Chapter 2: Soil Areas of Alabama

There are seven major soil areas in Alabama that are distinctly different from each

other based mainly on the parent materials these soils were formed from (Figure 1). The

parent material affects the fertility status of soil in these areas. The major soil areas are in

turn made up of small units called soil series. A soil series is defined as a part of the

landscape with similarities among its properties such as color, texture, arrangement of

soil horizons, and depth to bedrock (Mitchell and Loerch, 1999). The soil areas are

Limestone Valleys and Uplands, Appalachian Plateau, Piedmont Plateau, Coastal Plain,

Blackland Prairie, Major Flood Plains and Terraces and Coastal Marshes and Beaches :

i. Limestone Valleys and Uplands

Soils in this area were formed mainly in residuum weathered from limestones.

Topography is generally level to undulating and elevation of about 600 feet. Most of the

land is open and cropped to cotton or soybeans. Most of the soils of the uplands are

derived from cherty limestones with elevation of about 700 feet, and topography ranges

from level to very steep. Cotton and soybeans are major row crops. Much of the area is

used for pasture or forest.

ii. Appalachian Plateau

Most of the soils are derived from sandstone or shale. They have a loamy subsoil

and a fine sandy loam surface layer. Most slopes are less than 10 percent. Elevation is

about 1,300 feet. Corn, soybean, potatoes, and tomatoes are major crops.

iii. Piedmont Plateau

Most of the soils in this area are derived from granite, hornblende, and mica

schists. Elevations in most areas range from 700 to 1,000 feet, although in the Talladega

Hills, elevations range from 900 to 2,407 feet (highest point in Alabama). Topography is

rolling to steep. Most rolling areas were once cultivated but are now in pasture or forest.


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iv. Coastal Plain

Most of the soils in this area are derived from marine and fluvial sediments

eroded from the Appalachian and Piedmont plateaus. The area consists of Upper and

Lower Coastal Plains. Topography is level to very steep. Narrow ridgetops and broad

terraces are cultivated, but most of the area is in forest. Elevations range from 200 to

1,000 feet.

v. Blackland Prairie

This area of central and western Alabama is known as the "Black Belt" because of

the dark surface colors of many of the soils. These soils were derived from alkaline,

Selma chalk, or acid marine clays. Acid and alkaline soils are intermingled throughout

the area. Sumter soils, which are typical of the alkaline soils, are clayey throughout and

have a dark- colored surface layer and a yellowish colored subsoil. These clayey soils

contain a high percentage of smectitic clays and they shrink and crack when dry and

swell when wet. The area is level to undulating. Elevation is about 200 feet. Soybeans is

the main crop. Most of these soils are used for timber production and pasture.

vi. Major Flood Plains and Terraces

The soils are not extensive but important when they are found along streams and

rivers. They are derived from alluvium deposited by the streams. A typical area consists

of cultivated crops on the nearly level terraces and bottomland hardwood forest on the

flood plain of streams.

vii. Coastal Marshes and Beaches

The soils are not extensive. They are on nearly level and level bottomlands, tidal

flats, and beaches along the Mobile River, Mobile Bay, and the Gulf of Mexico. Most of

the soils are deep and very poorly drained. Elevation is from sea level to a few feet above

sea level.


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Figure 1: Soil areas of Alabama


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Chapter 3: Nutrient Status of Alabama Soils

Soils in Alabama have been in continuous production for more than 100 years

(Adams and Mitchell, 2000). Some have been fertilized regularly throughout that period

and so the addition of nutrients to those soils maybe not only a waste of resources but

could lead to environmental pollution. Most soils have not been fertilized adequately to

replenish the nutrients lost by crop uptake, leaching and erosion. Therefore, most soils in

Alabama require fertilizers for optimum crop production (Mask and Mitchell Jr., 1988).

Devoid of fertilizers, Alabama soils exhibit low plant nutrients status since most of the

parent materials from which they were formed were low in phosphorus (P) and potassium

(K). Furthermore, Alabama's relatively high temperatures (mean annual temperature =

63 F) and high rainfall (mean annual rainfall = 60 inches) have caused release of

nutrients which are either lost from fields through leaching or runoff. This is especially

common where soils have been cropped continuously and therefore the soil surface has

been allowed to undergo erosion (Adams and Mitchell, 2000). The soil organic matter

(SOM) content in Alabama soils is low because of rapid decomposition under high

temperature and rainfall conditions (Adams and Mitchell, 2000), leading to low cation

exchange capacity (CEC) and hence low nutrient status of soils. Therefore, unless these

major nutrients have been built up in soils by past fertilization and management practices,soils will need fertilizer for sustainable production (Adams and Mitchell, 2000).

Nutrient needs were originally determined by thousands of simple fertilizer

experiments conducted on farms throughout the State (Adams and Mitchell, 2000). Prior

to the establishment of soil testing laboratories in Alabama, fertilizer recommendations

were based on complicated experiments conducted on substations and experiment fields

located on the major soils throughout the State. This system is no longer adequate

because soils have been altered by past management. Properly managed soils have

become more productive over the past 40 years as fertilizer use has increased. Some

nutrients may have been depleted while others have been built up in soils, depending on

amounts supplied in fertilizers and amounts removed in harvested crops. General

fertilizer recommendations based on soil type are no longer practical because past

management practices now have more influence on soil fertility than does soil type. Soils


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separated only by a fence may differ more in fertility than the original unfertilized soils

located in the different regions of the State. Soil tests have been developed to determine

the fertility level of individual soils. This has required much field and laboratory research

at many locations over the years to calibrate test results with response to fertilizers in the

field. Reliable soil tests based on such research are now the only practical basis for

determining the needs of specific crops on the many soil situations now existing in

Alabama (Adams and Mitchell, 2000).

Chapter 4: Soil Testing

What is Soil Testing?

Soil testing is a process by which elements (phosphorus, potassium, calcium,

magnesium, sodium, sulfur, manganese, copper and zinc) are chemically removed from

the soil and measured for their "plant available" content within the sample. The quantity

of available nutrients in the sample determines the amount of fertilizer that is

recommended. A soil test also measures soil pH, humic matter and exchangeable acidity.

These analyses indicate whether lime is needed and, if so, how much to apply.

Objective of a Soil-testing Program

The basic objective of a soil-testing program is to give gardeners a service leading

to better and more economic use of fertilizers and better soil management practices for

increasing agricultural production. High crop yields cannot be obtained without applying

sufficient fertilizers to overcome existing deficiencies. Fertilizer recommendation from a

soil testing laboratory is based on carefully conducted soil analyses and the results of up-

to-date crop research, and it therefore provides very scientific information available forfertilizing that crop in that field. Each recommendation is based on a soil test taking into

account the values obtained by these accurate analyses, the research work so far

conducted on the crop in the particular soil areas, and the management practices of the

concerned gardener. The soil test with the resulting fertilizer recommendation is therefore

the actual connecting link between agronomic research and its practical application to the


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farmers fields. Although soil test and recommendations are very important for optimal

crop production, they are not the only practices recommended to the gardeners. Good

crop yields are the result of the application of other good management practices, such as

proper tillage, efficient water management, good seed, and adequate plant protection

measures. Soil testing is essential and is the first step in obtaining high yields and

maximum returns from the money invested in fertilizers.

According to Mitchell (1999), most Alabama soils are acid, with pH is usually

below 5.5. This low pH affects most garden plants and lime is recommended to raise the

pH to around 6.5. Most garden plants do best in a slightly acid soil (pH 6.0 to 7.0).

A soil sample must be taken at the right time and in the right way. Remember that

any recommendations based on a soil test can be no better than the soil sample from

which they are made. It is important to know that every square foot of soil can be

different. Soil pH and nutrients vary both across the surface of the soil and also with the

depth of the soil. Growers are urged to take great care to be sure that the sample

submitted represents as accurately as possible the area from which it is taken. The tools

used, the area sampled, the depth and the correct mix of the sample, the information

provided, and packaging all influence quality of the sample. What to consider when

collecting soil samples:

Soil Sampling

To obtain meaningful and accurate soil test results, it is important that you collect

soil samples from the correct depth and from multiple locations within your yard and

garden. You should schedule soil sampling to allow adequate time for soil analysis (~1-2

weeks) and fertilizer purchase prior to application. To obtain a representative soil sample,

a minimum of ten samples should be collected and mixed from both your garden and

each 1,000 square feet (sq ft) of lawn. Be sure to remove any mulch or lawn thatch before

collecting your soil samples. If there is a visual or textural difference from one side of

your garden or lawn to the other, submit separate samples. Samples may be submitted

moist or dry. If you decide to soil sample in the fall or mid-summer, it is best to wait at


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least 2 months after fertilization to give the fertilizer a chance to dissolve, disperse and be

used by plants.

Soil samples are typically collected using hand probes, hand augers (Figure 2),

spades or shovels. Unless it is the only option, you should avoid shovels and spades

because it is difficult to obtain the same amount of soil from each depth and location,

possibly biasing results. Hand augers are useful, especially when sampling at different

depths. An alternative tool to collect a 0 to 6 inch soil sample is a bulb planter (available

at most gardening stores). Preferably, many Extension offices have hand probes or augers

and may either lend you the tools or assist you in soil sampling. Tools should be cleaned

between each garden or area sampled and stored away from fertilizers to prevent

contamination.

Sampling Time

It is recommended that a soil sample be taken a few months before starting any

new garden. If the soil test report recommends liming, you will have enough time to

apply it and have it adjust the soil pH before you plant.

Sampling Depth

For home gardens, soil samples are generally collected 0 to 6 inches from the soil

surface. In some cases, soil samples may, in addition, been taken below the 6 inch depth.

Because nitrogen (N) (in the form of nitrate-N), sulfate-sulfur (sulfate-S) and chloride

(Cl) are very soluble and can more readily move down into the soil than other nutrients,

deeper soil samples may be collected and analyzed for these nutrients.


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Figure 2: Soil probe and auger

Sample each unique area separately

Each sample should represent only one soil type or area and for each unique area(Fig. 3). If one area of your yard seems healthy and another has bare or yellow areas,

sample healthy and unhealthy areas separately even if both are vegetable or flower

gardens, etc.

Sampling Pattern

Sample in a zigzag pattern throughout each sampling area; this avoids the

systematic error of following a pattern established for instance by cultivation equipment

and hence introducing a bias. Garden and cultivated areas should be sampled as deeply as

soil is tilled.

Take Composite Samples

Due to differences in soil properties over short distances, it is important that you

take a composite sample of the area to be tested. A composite sample is a collection of 15

to 20 uniform cores or slices of soil taken from random spots in a garden. For an accurate

test, place the samples from a given area into a bucket. Then mix this soil well and place

about 1 pint of the mixture into a soil sample box. Fill the soil test for completely.

Sampling equipment

Use a soil probe or auger (Fig 2),

spade, hand garden trowel, or shovel to

collect samples. Avoid using brass, bronze,

or galvanized tools as they will

contaminate samples with nutrients such as


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Analyzing the sample

This is the chemical extraction and testing procedure used by the laboratory.

Although laboratories may use different extraction and analysis techniques, the

procedures used must be correlated to plant growth and nutrient uptake. In addition,

quality control by the staff is essential for reliable and accurate results.

Soil Testing Laboratories

The time spent selecting a good laboratory can quickly pay for itself in the form

of accurate fertilizer recommendations and desired plant responses. Laboratories that are

part of the North American Proficiency Testing Program (NAPTP) should provide you

with results from their analysis of NAPTP soil samples that have known nutrient levels.

A fairly high degree of variability has been observed among laboratories (Jacobsen et al.,

2002); therefore, it is recommended that soil samples be sent to the same laboratory each

year to ensure greater consistency. A list of analytical laboratories in the region may be

found in the Appendix.

Some laboratories have standard packages that indicate what nutrients and other

soil parameters are tested. It is recommended that, at a minimum, N, phosphorus (P),

potassium (K), O.M., soluble salts and pH be tested.

Interpreting the analysis

The analytical results must be related to plant growth or yield. Extensive soil test

calibration research on the crops and soils of Alabama has been conducted and will

continue. For each nutrient, crop, and soil, a good calibration must show that plant

growth, yield, or nutrient uptake increases as the level of an extractable nutrient increases

up to a point where further increases in soil test levels fail to show significant or

economical increases of plant growth or yield.


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Using the results

When growers receive a soil test report and appropriate recommendations, they

must make certain practical decisions which may result in a modification of the given

recommendation. Some of these decisions may involve the following:

i. Using readily available fertilizers or ordering custom blended fertilizer.ii. Applying the same fertilizer grade to all fields or group of fields.iii. Ordering separate fertilizers for each field (or portion of a field) sampled.iv. Using premium fertilizers which contain secondary and micronutrients.v. Applying only those micronutrients specifically recommended for the crop.vi. Splitting fertilizer and/or lime applications.vii. Using starter fertilizers and foliar fertilizers to supplement recommendations.viii. Modifying nitrogen recommendations based upon comments on report.ix. Applying fertilizers with other materials such as herbicides.x. Modifying recommendations based upon current economic conditions.

These and many other considerations affect how the soil test results are used, and

is a decision the grower or crop advisor must make.


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Figure 3: An illustration of the procedure for taking soil sample (adopted from Mitchell

(1999).


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Chapter 5: Nutrient Recommendations for Alabama Garden Crops

(Adopted from Mitchell (1999)

A. Organic Vegetable Garden

Phosphorus Potassium

Very high High Medium Low Very low

Pounds N-P2O5-K2O per acre

Very high 1 1 1,2 1,2 1,2

High 3 3 5,5,2 4,5,2 4,5,2

Medium 6 6 6,2 6,2 6,2

Low 6,7 6,7 6,7,2 6,7,2 6,7,2

Very Low 6,7 6,7 6,7,2 6,7,2 6,7,2

Comments

1 - Soil analyses indicate very high or excessive P. Additional organic amendments will

add more P. Use materials high in N but low in P such as cottonseed meal (6-3-1), fish

meal (10-6-1), or blood meal (13-2-1). Legume cover crops can also provide some N to

subsequent crops.

2 - Organic materials generally provide less K compared to N and P. K can be supplied

with "green sand" (6% K2O ), or potassium magnesium sulfate (18% K2O, 11% Mg, 22%

S). Apply enough material to supply one to three pounds K2O per 1,000 square feet.

3 - Soil analyses indicate adequate K and P for most vegetables. To supply N for non-

legumes, use materials high in N but low in K such as cottonseed meal (6-3-1), fish meal

(10-6-1), or blood meal (13-2-1). Legume cover crops can also provide some N to

subsequent crops.

4 - P is adequate for most crops.


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5 - To supply N for non-legumes use materials high in N but low in P such as cottonseed

meal (6-3-1), fish meal (10-6-1), or blood meal (13-2-1). Legume cover crops can also

provide some N to subsequent crops.

6 - Most manures and composts will provide some N and P. Apply enough material to

provide approximately three pounds N and three pounds P2O5 per 1,000 square feet

during the growing season.

7 - Low soil P can be corrected by using bone meal (1-15-0) or rock phosphate (2-35%

P2O5 ) to provide two to three pounds P2O5 per 1,000 square feet.

8 - Final comment. Most organic materials contain low levels of available nutrients.

However, because large quantities are often used to build soil organic matter and improve

soil physical characteristics, soil nutrients, (i.e. P) often build to excessive levels.

Nutrient availability (especially N) depends upon how fast the organic matter breaks

down in the soil. Following are typical analyses (percent N-P2O5-K2O) of some common

materials used as soil amendments in organically grown gardens:

B. Home Vegetable Garden




Very high 120-0-01

120-0-602

120-0-1203

120-0-1804

120-0-1804

High 120-60-05

120-60-606

120-60-1207

120-60-1808

120-60-1808

Medium 120-120-09

120-120-6010

120-120-12011

120-120-18012

120-120-18012

Low 120-180-013 120-180-6014 120-180-12015 120-180-18016 120-180-18016

Very Low 120-180-013

120-180-6014

120-180-12015

120-180-18016

120-180-18016


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Comments

One ton limestone per acre is approximately equivalent to 50 pounds per 1,000 square

feet. For cauliflower, broccoli, and root crops on sandy soils apply one pound boron (B)

per acre. For strawberries apply about one-third of the fertilizer in September, one-third

about 90 days before ripening, and one-third after harvest.

1- Per 100 feet of row apply 0.4 pound N (one pint ammonium nitrate) at planting and

side-dress with 0.4 pound N.

2- Per 1,000 square feet broadcast 2.3 pounds muriate of potash (one quart). Per 100 feet

of row apply 0.4 pound N (one pint ammonium nitrate) at planting and sidedress with 0.4

pound N.

3- Per 1,000 square feet broadcast 4.6 pounds muriate of potash (two quarts). Per 100

feet of row apply 0.4 pound N (one pint ammonium nitrate) at planting and sidedress with

0.4 pound N.

4- Per 1,000 square feet broadcast seven pounds muriate of potash (three quarts). Per 100

feet of row apply 0.4 pound N (one pint ammonium nitrate) at planting and sidedress with

0.4 pound N.

5- Per 1,000 square feet broadcast 7.5 pounds superphosphate (four quarts). Per 100 feet

of row apply three pounds 13-13-13 (1.5 quarts) at planting and sidedress with 0.4 pound

N (one pint ammonium nitrate).

6- Per 100 feet of row apply five pounds of 13-13-13 (2.5 quarts) at planting and

sidedress with 0.4 pound N (one pint ammonium nitrate).





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8- Per 1,000 square feet broadcast 4.6 pounds muriate of potash (two quarts). Per 100

feet of row apply three pounds 13-13-13 (1.5 quarts) at planting and sidedress with 0.4

pound N (one pint ammonium nitrate).

9 - Per 1,000 square feet broadcast 15 pounds superphosphate (eight quarts). Per 100 feet

row apply three pounds 13-13-13 (1.5 quarts) at planting and sidedress with 0.4 pound N.

10- Per 1,000 square feet broadcast 7.5 pounds superphosphate (four quarts). Per 100 feet



11- Per 100 feet of row apply four pounds 13-13-13 (two quarts) at planting and sidedress

with 2.5 pounds 13-13-13 (five cups).


of row apply four pounds 13-13-13 (two quarts) at planting and sidedress with 2.5 pounds

13-13-13 (five cups).

13- Per 1,000 square feet boradcast 20 pounds superphosphate (11 quarts). Per 100 feet of

row apply 0.4 pound N (one pint ammonium nitrate) at planting and sidedress with 0.4

pound N.

14- Per 1,000 square feet broadcast 7.5 pounds superphosphate (4 quarts). Per 100 feet of

row apply four pounds 13-13-13 (two quarts) at planting and sidedress with 0.4 pound N

(one pint ammonium nitrate).

15- Per 1,000 square feet broadcast 7.5 pounds superphophate (four quarts). Per 100 feet

of row apply four pounds 13-13-13 (two quarts) at planting and sidedress with 2.5 pounds

13-13-13 (five cups).

16- Per 1,000 square feet broadcast 35 pounds 4-12-12 at planting. Per 100 feet of row

sidedress with 0.4 pound N (one pint ammonium nitrate).


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Final remark. For small areas, comments give examples of ways to meet the fertilizer

recommendations. Other fertilizer grades or materials that supply equivalent amounts of

plant nutrients may be used with equal results. If you need assistance in calculating

amounts of other materials to use contact your county agent or fertilizer supplier.

K requirement

level2 N rate 120

Lime code no. 1

PK

code

no.

21

Mg code no. 2

C. Commercial Vegetable Crops

(Crop Code No. 61)




Very high 120-0-0 120-0-60 120-0-120 120-0-180 120-0-180

High 120-60-0 120-60-60 120-60-120 120-60-180 120-60-180

Medium 120-120-0 120-120-60 120-120-120 120-100-180 120-120-180

Low 120-180-0 120-180-60 120-180-120 120-180-180 120-180-180

Very Low 120-180-0 120-180-60 120-180-120 120-180-180 120-180-180


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For more accurate fertilizer recommendations, use the equations below for your soil

group:

Fertilizer Recommendation Formula

P2O5 K2O

Soil Group* Equation** Soil Group* Equation**

1 & 2 Y = 180 - 1.91X 1 Y = 190 - 1.08X

3 Y = 180 - 3.16X 2 Y = 190 - 0.98X

4 Y = 180 - 1.33X 3 Y = 190 - 0.53X

4 Y = 200 - 0.52X

* - Use Soil Group from soil test report, if available.

** - Y = pounds fertilizer P2O5 or K2O per acre required; X = soil test P or K

Comments

For cauliflower, broccoli, and root crops, apply one pound of B per acre.

K requirementlevel

2 N rate 120

Lime code no. 1

PK

code

no.

18

Mg code no. 2


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D. Tomatoes

(Crop Code No. 62)




Very high 120-0-0 120-0-60 120-0-120 120-0-180 120-0-180

High 120-60-0 120-60-60 120-60-120 120-60-180 120-60-180

Medium 120-120-0 120-120-60 120-120-180 120-120-180 120-120-180

Low 120-180-0 120-180-60 120-180-120 120-180-180 120-180-180

Very Low 120-180-0 120-180-60 120-180-120 120-180-180 120-180-180


group:


P2O5 K2O


1 & 2 Y = 180 - 1.91X 1 Y = 190 - 1.08X

3 Y = 180 - 3.16X 2 Y = 190 - 0.98X

4 Y = 180 - 1.33X 3 Y = 190 - 0.53X

4 Y = 200 - 0.52X




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Comments

Apply 1,000 pounds of gypsum per acre to tomatoes before planting. (Where Ca is rated

low and no lime is recommended.)

Apply 500 pounds of gypsum per acre to tomatoes before planting. (Where Ca is rated

medium and no lime is recommended.)

K requirement

level2 N rate 120

Lime code no. 2

PK

code

no.

18

Mg code no. 2

E. Irish Potatoes

(Crop Code No. 64)




Very high 120-50-0 120-50-100 120-50-150 120-50-200 120-50-200

High 120-100-0 120-100-100 120-100-150 120-100-200 120-100-200

Medium 120-150-0 120-150-100 120-150-150 120-150-200 120-150-200

Low 120-200-0 120-200-100 120-200-150 120-200-200 120-200-200

Very Low 120-200-0 120-200-100 120-200-150 120-200-200 120-200-200


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group:


P2O5 K2O


1 & 2 Y = 200 - 1.59X 1 Y = 210 - 0.88X

3 Y = 200 - 2.64X 2 Y = 210 - 0.59X

4 Y = 200 - 1.11X 3 Y = 210 - 0.43X

4 Y = 220 - 0.44X



Comments

Where Irish potatoes are grown in rotation with other crops, follow lime recommendation

for Irish potatoes.

K requirement

level2 N rate 120

Lime code no. 4

PK

code

no.

17

Mg code no. 3


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F. Watermelons, Cantaloupes, Cucumbers, Lima Beans, Snap Bunch Beans, Squash, and

Okra

(Crop Code No. 65)




Very high 80-0-0 80-0-40 80-0-80 80-0-120 80-0-120

High 80-40-0 80-40-40 80-40-80 80-40-120 80-40-120

Medium 80-80-0 80-80-40 80-80-80 80-80-120 80-80-120

Low 80-120-0 80-120-40 80-120-80 80-120-120 80-120-120

Very Low 80-120-0 80-120-40 80-120-80 80-120-120 80-120-120


group:


P2O5 K2O


1 & 2 Y = 120 - 1.27X 1 Y = 130 - 0.72X

3 Y = 120 - 2.11X 2 Y = 130 - 0.48X

4 Y = 120 - 0.89X 3 Y = 130 - 0.35X

4 Y = 130 - 0.35X




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group:


P2O5 K2O


1 & 2 Y = 180 - 1.91X 1 Y = 190 - 1.08X

3 Y = 180 - 3.16X 2 Y = 190 - 0.98X

4 Y = 180 - 1.33X 3 Y = 190 - 0.53X

4 Y = 200 - 0.52X



K requirement

level2 N rate 100

Lime code no. 2

PK

code

no.

18

Mg code no. 2


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REFERENCES

Adams, J.F., and C.C. Mitchell Jr. 2000. Soil test nutrient recommendations for Alabamacrops: Nutrient recommendations for cotton.

www.ag.auburn.edu/agrn//croprecs/CropRecs/cc10.html.

Dinkins, P. 2008. Home Garden Soil Testing & Fertilizer Guidelines. Montana State

University Extension. MT200705AG Revised /08.

http://msuextension.org/publications/YardandGarden/MT200705AG.pdf

Mask P. L., and C. C. Mitchell, Jr.1988. Alabama Production Guide for Non-Irrigated

Corn. (ANR-503). Alabama Cooperative Extension Service, Auburn University andUSDA-NRCS.

Mitchell, Jr., C.C. and J. C. Loerch. 1999. Soils of Alabama (ANR-340 Revised

Jan1999). Alabama Cooperative Extension Service, Auburn University and USDA-

NRCS.

Documents

Soil Testing Guide for Home Gardening in Alabama