[FONT="]Nutrient[/FONT][FONT="][/FONT]
| [FONT="]Action Mode[/FONT][FONT="][/FONT]
| [FONT="]Deficiency[/FONT][FONT="][/FONT]
| [FONT="]Excess[/FONT][FONT="][/FONT]
| [FONT="]Comments[/FONT][FONT="][/FONT]
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[FONT="]Nitrogen (N)[/FONT]
| [FONT="]Absorbed as NO3-, NH4+; responsible for rapid foliage growth and green color; easily leaches from soil, especially NO3-; mobile in plant, moving to new growth[/FONT]
| [FONT="]Reduced growth, light green to yellow foliage (chlorosis); reds and purples may intensify with some plants; reduced lateral breaks; symptoms appear first on older growth[/FONT]
| [FONT="]Succulent growth, leaves are dark green, thick and brittle; poor fruit set; excess ammonia can induce calcium deficiency[/FONT]
| [FONT="]The best NH4+/NO3- ratio is 1/1; high NH4+ under low light can cause leaf curl; uptake inhibited by high P levels; indoors, best N/K ratio is 1/1 unless light is extremely high; in soils with high C/N ratio more N should be supplied.[/FONT]
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[FONT="]Phosphorus (P)[/FONT]
| [FONT="]Promotes root formation and growth; affects quality of seed, fruit and [/FONT][FONT="]flower production[/FONT][FONT="]; increased disease resistance; does not leach from soil readily; mobile in plant, moving to new growth[/FONT]
| [FONT="]Reduced growth; leaves dark green; purple or red color in older leaves, especially on the underside of the leaf along the veins; leaf shape may be distorted; thin stems; limited root growth[/FONT]
| [FONT="]Shows up as micronutrient deficiency of Zn, Fe, or Co[/FONT]
| [FONT="]Rapidly "fixed" on soil particles; when applied under acid conditions, fixed with Fe, Mn and Al; under alkaline conditions fixed with Ca; high P interferes with micronutrient and N absorption; used in relatively small amounts when compared to N and K; availability is lowest in cold soils.[/FONT]
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[FONT="]Potassium (K)[/FONT]
| [FONT="]Helps plants overcome drought stress; improves winter hardiness; increased disease resistance; improves the rigidity of stalks; leaches from soil; mobile in plant[/FONT]
| [FONT="]Reduced growth; shortened internodes; margins of older leaves become chlorotic and burn; necrotic (dead) spots on older leaves; reduction of lateral breaks and tendency to wilt readily; poorly developed root systems; weak stalks[/FONT]
| [FONT="]Causes N deficiency in plant and may affect the uptake of other positive ions such as Mg and Ca[/FONT]
| [FONT="]High N/low K favors vegetative growth; low N/high K promotes reproductive growth (flower, fruit); calcium excess impedes uptake of potassium[/FONT]
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[FONT="]Magnesium (Mg)[/FONT]
| [FONT="]Absorbed as Mg++; leaches from sandy soil; mobile in plant[/FONT]
| [FONT="]Reduction in growth; yellowish, bronze, or reddish color of older leaves, while veins remains green; leaf margins may curl downward or upward with a puckering effect[/FONT]
| [FONT="]Interferes with Ca uptake; small necrotic spots in older leaves; smaller veins in older leaves may turn brown; in advanced stage, young leaves may be spotted[/FONT]
| [FONT="]Mg is commonly deficient in foliage plants because it is leached and not replaced; epsom salts at a rate of 1 teaspoon per gallon may be used two times a year; Mg can be absorbed by leaves if sprayed in a weak solution; dolomitic limestone can be applied in outdoor situations to rectify a deficiency[/FONT]
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[FONT="]Calcium (Ca)[/FONT]
| [FONT="]Absorbed as Ca++; moderately leachable; limited mobility in plant; essential for growth of shoot and root tips; reduces the toxicity of aluminum and manganese[/FONT]
| [FONT="]Inhibition of bud growth; roots can turn black and rot; young leaves are scalloped and abnormally green; leaf tips may stick together; cupping of maturing leaves; blossom end rot of many fruits, pits on root vegetables; stem structure is weak; premature shedding of fruit and buds[/FONT]
| [FONT="]Interferes with Mg absorption; high Ca usually causes high pH which then precipitates many of the micronutrient so they become unavailable to the plant[/FONT]
| [FONT="]Ca is rarely deficient if the correct pH is maintained; too much or too little water, can affect Ca relationships within the plant causing deficiency in the location where Ca was needed at the time of stress[/FONT]
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[FONT="]Sulfur (S)[/FONT]
| [FONT="]Absorbed as SO4-; leachable; not mobile; contributes to odor and taste of some vegetables[/FONT]
| [FONT="]Rarely deficient; general yellowing of the young leaves then the entire plant; veins lighter in color than adjoining interveinal area; roots and stems are small, hard and woody[/FONT]
| [FONT="]Sulfur excess is usually in the form of air pollution[/FONT]
| [FONT="]Sulfur excess is difficult to control but rarely a problem.[/FONT]
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