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Tuesday, January 29, 2008

Primary Nutrients

Primary Nutrients:

  • Nitrogen (N) N > 10ppm

Pre-plant N generates vigorous seedling growth, which ensures a well-branched plant by the first fruit set. Pre-plant N is not needed if a soil test shows the soil has 20ppm nitrate or more Broadcast 20-30lbsN/ac before discing of N is needed, otherwise, band N (2-5lbs/ac) 3-4 inches below the seed. Apply a steady supply of N to the plant during first set to produce greater yields. While plants develop first fruits, analyze plant tissue samples to keep nitrate concentration in the plant stem and petiole between 7000-8000ppm. High N rates may depress total yields, delaying crop maturity and decrease the proportion of red pods.

Symptoms of Nitrogen Deficiency

    1. Slow growth; stunting
    2. Yellow-green color (chlorosis)
    3. "Firing" of tips and margins of leaves beginning with more mature leaves.
  • Phosphorus (P) N > 30ppm

Helps young seedling grow, especially when soil warms in spring. Not needed if levels of soil P are between medium and medium-low. Add 50-100lbs P2O5/ac before discing of levels are lower. Alternatively, band 30lbs P2O5/ac 3-4 inches below the seed. P increases total yield and increases the proportion of red pods. Important for good root development and fruit production.

Symptoms of Phosphorus Deficiency

    1. Slow growth; stunting.
    2. Purplish coloration on foliage of some plants.
    3. Dark green coloration with tips of leaves dying.
    4. Delayed maturity
    5. Poor fruit or seed development.
  • Potassium (K) N > 150ppm

Encourages root growth and increases plant resistance to disease. Increases size and quality of fruit and vegetables and increases winter hardiness. It is mobile in the plant Fertilizer form is K2O

Symptoms of Potassium Deficiency

    1. Tip and margin "burn" starting on more mature leaves.
    2. Weak stalks, plants "lodge" easily.
    3. Small fruits or shriveled seed.
    4. Slow growth.

Secondary Nutrients:

  • Calcium (Ca)

A structural nutrient, it is an essential part in all walls and membranes and must be present for the formation of new cells.
-Non-mobile in plant tissue

Symptoms of Calcium Deficiency

    1. "Tip burn" of young leaves-celery, lettuce, cabbage.
    2. Death of growing points (terminal buds). Root tips also affected.
    3. Abnormal dark green appearance of foliage.
    4. Premature shedding of blossoms and buds.
    5. Weakened stems.
    6. Water-soaked, discolored areas on fruits- blossom-end rot of peppers.
  • Magnesium (Mg)

Essential for photosynthesis. Serves as an activator for many plant enzymes required in growth process.
-Mobile within the plant and can be readily translocated from older to younger tissue.

Symptoms of Magnesium Deficiency

    1. Interveinal chlorosis in older leaves.
    2. Curling of leaves upward along margins.
  • Sulfur (S)

A constituent of three amino acids (cystine, methionine, cysteine), therefore essential for protein synthesis.

Symptoms of Sulfur Deficiency

    1. Young leaves light green to yellowish color.
    2. Small and spindly plants.
    3. Retarded growth rate and delayed maturity.


Even though they used by plants in very small amounts, they are just as essential for plant growth as the larger amounts of primary and secondary nutrients. Care must be exercised in the use of micronutrients, since the difference between deficient and toxic levels if often small. Micronutrients should not be applied as a ÒshotgunÓ application to cover possible deficiencies. They should be applied only when the need has been demonstrated.

  • Zinc (Zn)

An essential constituent of several important enzyme systems. Controls the synthesis of indoleacetic acid (IAA), an important plant growth regulator.

Symptoms of Zinc Deficiency

    1. Decrease in stem length and a rosetteing of terminal leaves.
    2. Reduced fruit bud formation.
    3. Mottled leaves (interveinal chlorosis).
  • Iron (Fe)

Required for the formation of chlorophyll in plant cells. Serves as an activator for biochemical processes such as respiration, photosynthesis, and symbiotic nitrogen fixation.

Symptoms of Iron Deficiency

    1. Interveinal chlorosis of young leaves. Veins remain green except in severe cases.
  • Manganese (Mn)

Serves as an activator for enzymes in growth processes. Assist Fe in chlorophyll formation. High Mn concentration may induce Fe deficiency.

Symptoms of Manganese Deficiency

    1. Interveinal chlorosis of young leaves.
    2. Gradation of pale green coloration with darker color next to veins. No sharp distinction between veins and interveinal areas as with Fe deficiency.
  • Copper (Cu)

An activator of several enzymes. May play a role in vitamin A production. A deficiency interferes with protein synthesis.

Symptoms of Copper Deficiency

    1. Stunted growth.
    2. Poor pigmentation.
    3. Wilting and eventual death of leaf tips.
  • Boron (B)

Functions in plants in differentiation of meristem cells. With B deficiency, cells may continue to divide, but structural components are not differentiated. Also, apparently regulates metabolism of carbohydrates in plants. Once assimilated, B is not remobilized in plants, and a continuous supply is necessary at all growing points. Deficiency is first found in the youngest tissue of the plant.

Symptoms of Boron Deficiency

    1. Death of terminal growth, causing lateral buds to develop and producing a ÒwitchesÕ-broomÓ effect.
    2. Thickened, curled, wilted, and chlorotic leaves.
    3. Reduced flowering or improper pollination.
  • Molybdenum (Mo)

Required by plants for utilization of nitrogen. Plants cannot transform nitrate nitrogen into amino acids with Mo.

Symptoms of Molybdenum Deficiency

    1. Stunting and lack of vigor.
    2. Marginal scorching and cupping or rolling of leaves.
  • Chlorine (Cl)

Required in photosynthetic reactions in plants. Deficiency is very rare due to its universal presence in nature.

Symptoms of Chlorine Deficiency

    1. Wilting followed by chlorosis.
    2. Excessive branching of lateral roots.
    3. Bronzing of leaves.
    4. Chlorosis and necrosis.

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