Msg # 5154   
Date: 04 May 93 08:06:00
From: Jeff Burns
  To: All
Subj: More stuff
____________________________________________________________________________

AREA:SUST_AG
MSGID: 1:346/16.0 2be65c3c
Summary of Roles of Mineral Elements in Plant Nutrition

                       Primary Nutrients


Element:  Nitrogen

Function in Plants:  Synthesis of amino acids, proteins, chlorophyll, nucleic
acids and coenzymes.

Forms in the soil: Organic compounds, nitrites, nitrates, and ammonium
(soluble forms).

Deficiency Symptoms:  Stunted growth, thin stems, delayed maturity, light
green leaves: lower leaves turn yellow and die (chlorosis).

Losses from soil:  Erosion, leaching, crop removal.

Organic Fertilizers: Legume crops; animal manures, crop residues, animal
waste.

Natural sources: Organic matter; atmospheric nitrogen fixed by microbes;
small amounts disolved in water.

Deficiency may be induced by excess of: Carbon, phosphorus

Excess may induce a deficiency of: Phosphorus

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Element: Phosphorus

Function in plant: Used in proteins, nucleoproteins, metabolic transfer
processes, ATP, ADP, photosynthesis, and respiration. Component of
phospholipids.

Forms in the soil: Organic compounds; soluble phosphates; insoluble compounds
of iron, aluminum, manganese, magnesium, and calcium.

Deficiency symptoms:  Purplish leaves, stems, and branches; reduced yeils of
seeds and fruits, stunted growth, stunted roots.

Losses from soil: crop removal, fixation in soil. Reversion to unavailable
form in soil.

Natural sources: Organic matter; mineral powders; some parent materials,
animal manures.

Deficiency may be induced by excess of: Calcium, nitrogen, iron, aluminum,
manganese.

Excess may induce a deficiency of: Zinc, copper, nitrogen.

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Element: Potassium

Function in plant: Sugar and starch formation, synthesis of protiens.
Catalyst for enzyme reactions, neutralizes organic acids, growth of
meristemtic tissue.

Forms in soil:  Available as K+ on cation exchange sites or in soil solution.
(less than 1% of total soil K+ is in avalible form).

Deficiency symptoms: Reduced yields; mottled, spotted or curled older leaves;
marginal burning of leaves; weak root system, weak stalks.

Losses from soil: Crop removal.  Soil fixation, leaching.

Natural sources: Feldspars; mica; granites; certain clays.

Deficiency may cause an excess of: Magnesium, calcium, ammonium.

Excess may induce a deficiency of: Magnesium, boron

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                       Secondary Nutrients

Element: Calcium

Function in plant: Cell walls, cell growth and division; nitrogen
assimilation.  Cofactor for some enzymes.

Forms in soil: Most is present as Ca++ ion on cation exchange sites, or in
soil solution.

Deficiency symptoms: Deformed terminal leaves, reduced root growth.  Some
plants turn black, dead spots in midrib in some plants.  Failure of terminal
bud.

Losses from soil: leaching, crop removal.

Natural sources: Dolomite, calcite, apatite, calcium feldspars.

Deficiency may be induced by excess of: Aluminum

Excess may induce a deficiency of Magnesium, potassium, iron, manganese,
zinc, phophorus, boron.

--- Maximus 2.00
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