Absorbed as NO3-, NH4.
Succulent growth, dark green color, weak spindly growth, few fruits, may cause brittle growth especially under high temperatures.
Reduced growth, yellowing, reds and purples may intensify with some plants, reduced lateral bud breaks. Symptoms appear first on older growth.
In general, the best NH4/NO3- ratio is 1:1.
Absorbed as H2PO4-, HPO4-.
Shows up as micronutrient deficiency of Zn, Fe, or Co
Reduced growth, color may intensify, browning or purpling in foliage in some plants, thin stems, reduced lateral bud breaks, loss of lower leaves, reduced flowering.
Rapidly "fixed" on soil particles when applied under acid conditions fixed with Fe, Mg and Al.
Leaches from soil absorbed as K+.
Causes N deficiency in plants and may affect the uptake of other positive ions.
Reduced growth, shortened internodes, marginal burn or scorch (brown leaf edges), necrotic (dead) spots in the leaf, reduction of lateral bud breaks and tendency to wilt readily.
N/K balance is important.
Absorbed as Mg++.
Interferes with Ca uptake.
Reduction in growth, marginal chlorosis, interveinal chlorosis (yellow between the veins) in some species. May occur with middle or lower leaves, reduction in seed production, cupped leaves.
Mg is commonly deficient in foliage plants because it is leached and not replaced. Epsom salts at a rate of 1 teaspoon per gallon of water may be used 2 times a year. Mg can also be absorbed by leaves if sprayed in a weak solution. Dolomitic limestone can be applied in outdoor situations to rectify a deficiency.
Interferes with Mg absorption. High Ca usually causes high pH which then precipitates many of the micronutrients so that they become unavailable to the plant.
Inhibition of bud growth, death of root tips, cupping of maturing leaves, weak growth, blossom end rot of many fruits, pits on root vegetables, apples, and pears.
Ca is important in controlling pH and is rarely deficient if the correct pH is maintained. Water stress, too much or too little, can affect Ca relationships within the plant causing deficiency in the location where Ca was needed at the time of stress.
Absorbed as SO4-.
Sulfur excess is usually in the form of air pollution.
S is often a carrier or impurity in fertilizers and rarely deficient. It may be also absorbed from the air and is a by-product of combustion. Symptoms are a general yellowing of the affected leaves or the entire plant.
Sulfur excess is difficult to control.
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