Clemson University Cooperative Extension Service

Clemson University Cooperative Extension Service



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Clemson University Cooperative Extension ServicepH Factor

Alk

alin

ity

Incre

ase

s

Alk

alin

ity

Decre

ases

Pure Water pH 7.0 Neutral

Soap Solution pH 9.3 Sea Water pH 7.9 AlkalineHuman Blood pH 7.3

Fresh Milk pH 6.7 Sour Milk pH 4.7 Acid Orange Juice pH 3.7Lemon Juice pH 2.4

•Distinct resistance to pH change of soil solution

•Equilibrium between active and reserve acidity

•Stabilizes soil pH

•Larger the buffering capacity, larger quantity of lime or sulfur needed


BACTERIA

• Raises soil pH

• Amount applied needs to be determined by soil test

• Needs to be applied 3 to 4 months prior to planting

• Maximum contact with soil is important

• Moisture is essential for reaction

• Be aware of neutralizing value of liming material

• Supplies CA and Mg if dolomitic limestone is used

• Makes other essential elements more available

• Prevents Mn and Al from becoming toxic


•Deficiencies of available Fe, Mn, Cu, and Zn

•Decrease in phosphate availability by Ca

•Restricted uptake of P

•Uptake and utilization of boron hindered

•Drastic change in soil pH


•Surface soil: pH, texture and structure, OM

•Subsurface soil: pH, texture and structure

•Crops to be grown

•Kind and fineness of lime used

•Economic returns in relation to cost of lime used





Nitrogen - (N)

Phosphorous - (P)

Potassium - (K)


Sulfur - (S)

Calcium - (Ca)

Magnesium - (Mg)


Iron - (Fe) Copper - (Cu)

Manganese - (Mn) Boron - (B)

Chlorine - (Cl) Zinc - (Zn)

Molybdenum - (Mo)





•Organic nitrogen associated with soil humus

•Ammonium nitrogen fixed by certain clays

•Soluble inorganic ammonium and nitrate forms


General pale green to yellowing leaf color, followed by tissue death and leaf drop. Overall growth of plant is stunted with reduced yields. Older leaves of the plant will be affected first.



Common Nitrogen sources

Material % N

Ammonium Nitrate 34Ammonium Sulfate 21 Calcium Nitrate 16Sodium Nitrate 16Potassium Nitrate 13Urea 45Organic 9-12

Ammonium - NH4

Nitrate - NO3


R-NH2 + HOH R-OH + NH3 + energy

2NH3 + H2CO3 (NH4)2CO3 2NH4 + CO3

ORGANIC ENZYMES

Occurs quickest in well-drained, aerated soils with basic cations present.


2NH4 + 3O2 2NO2 + H2O + 4H + energy

2NO2 + O2 2NO3 + energy

ENZYMES+ - +

- -ENZYMES

Affected by soil aeration, temperature, moisture, active lime, fertilizer salts, C/N ratio.


2NO3 2NO2 N2O N2 Nitrates Nitrites Nitrous oxide N gas

Occurs most often on alkaline soils under anaerobic conditions after a heavy application of urea or ammonium fertilizer.


•Used by microorganisms

•Used by higher plants

•Lost in drainage

•Escape the cycle in gaseous form



Cell division Crop quality

Flowering and fruiting Disease resistance

Crop maturation Energy Flow

Root development

Plant strength


Leaves develop a blue-green or red-purple discoloration possibly yellowing. You will see poor fruit and seed development. The plant will also show a slow, stunted growth. More prevalent in early spring before soil temperatures rise.



Common Phosphorous sources

Material % P (P205)

Ordinary superphosphate 20Concentrated superphosphate 46 Organic 9-12

•Soil pH

•Soluble iron, aluminum and manganese

•Available calcium and calcium minerals

•Amount and decomposition of OM

•Activities of microorganisms


H2 PO4 H2O + HPO4 H2O + PO4

Very acid solution

Very alkaline solution

Al CaP is most available at a pH of between 6.0 and

7.0



90 to 98% of K is locked in soils

Only a very small portion is available in the plow layer of most soils. This will range from 50 to 500 lbs K per acre.


•Absorbed as much as N

•Disease resistance

•Encourages strong roots

•Delays maturity

•Essential for photosynthesis

•Energy formation

•Energy translocation

•Necessary for tubers


•Slow growth

•Browning of tips

•Red or purple tips

•Reduced disease resistance

•Sparse foliage

•Shoot dieback



Common Potassium sources

Material % K (K20)

Muriate of Potash 60-62Potassium Nitrate 46 Potassium Sulfate 50Sulfate of Potash Magnesia 22Organic 1-2%



Leaf tips will become distorted and dieback (scorched), young leaves will show chlorotic, hard, stiff margins that are distorted. You will also see a premature shedding of blossoms and buds. Evidence of weakend stems and water-soaked, discolored areas on fruit such as blossom-end rot on tomatoes, peppers and melons.




.Magnesium is the key element in the chlorophyll molecule.

Common Mg sources

Material % Mg

Dolomitic Lime 6-11Magnesia 55 Mg Sulfate 17

Marginal and interveinal yellowing beginning along the main rib vein progressing to cupped, brittled leaves.




— Essential in protein formation

— Helps develop enzymes and vitamins

— Promotes nodule formation on legumes

— Aids in seed production

— Necessary in chlorophyll production


Although sulfur occurs in the soil as the sulfate ion (SO4

=), the major source of sulfur is derived from organic matter. Therefore, the amount of organic matter in the soil and the rate of its decomposition is important in sulfur availability .


Fe

Mn

Cu

Mo

BZn


Micronutrients can become deficienct through:

a) highly leached soilsb) muck soilsc) soils very high in pH d) soils which have been heavily cropped and fertilized with macronutrients only



Fertilizer grade refers to how much of an element is contained in a formulation based on weight.

Nitrogen (N)Phosphate (P2O5)Potassium (K2O)


The ration describes the relative proportion of N, P2O5 and K2O in a fertilizer. A 16-4-8 fertilizer is considered a 4:1:2 ratio.


A fertilizer is considered complete when it contains each of the three major plant nutrients. Examples include 10-10-10, 16-8-8 and 5-10-10.


A fertilizer is considered balanced when it contains an equal amount of the three major nutrients such as 10-10-10, 6-6-6 0r 18-18-18.


An incomplete fertilizer lacks on or more of the major nutrients such as 15-0-15, 0-0-60 or 0-45-0.


• Materials that dissolve slowly such as granite meal, greensand and rock phosphate.

• Materials from which nitrogen is released slowly by microbes.

• Granular material that are contained within a coating. These may be microbe or environmentally released.



•Inorganic: various salts and minerals

•Synthetic organic: human made organic material used as fertilizers

•Natural organic: applied to fertilizers derived solely from the remains or by-products from a once living organism

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Clemson University Cooperative Extension Service