I. ESSENTIAL ELEMENTS
 
 

II. MACRONUTRIENTS

    A. Nitrogen (N)

            1) The Soil Nitrogen Cycle

                Nitrogen fixation - Transformation of atmospheric N to nitrogen forms available to plants
                      N-fixing bacteria - Rhizobium (symbiotic) in legumes (soybean, peas, honeylocust; species in Farbaceae)
                                                      Azotobacter (non-symbiotic)

           Ammonification and Nitrification

            2) N Functions in Plants
                - component of proteins, enzymes, amino acids, nucleic acids, chlorophyll
                - C/N ratio (Carbohydrate : Nitrogen ratio)
                                    High C/N ratio-----Reproductive
                                    Low C/N ratio-----Vegetative
                - Transamination
                    NO₃        >NH₂      >Glutamic Acid (a.a)          > other a.a.       >Protein, Enzyme
                - Essential for fast growth, green color

            3) Deficiency and Toxicity Symptoms
                Deficiency:    Reduced growth
                                    Yellowing of old leaves

                                    Protein degradation        >amino acids       >move to new leaves
                           (old leaf)

            4) Fertilizers

               

                -Ammonium Nitrate (NH₄NO₃) (cheap)
                 Calcium Nitrate (CaNO₃) (expensive)
                 Potassium Nitrate (KNO₃) (expensive)
                 Urea (CO(NH₂)₂) (cheap)
                -Most plants prefer       50 : 50         NH₄⁺ : NO₃^-             2:5
                 NH₄⁺ form of Nitrogen ------- Soil pH lowers  (good for blueberry, Azalea)
                 NO₃^- form of Nitrogen ------- Soil pH increases
                -Organic fertilizer (manure, plant residue)- slow acting
                -Can be applied foliarly

    B. Phosphorus (P)
            1) Soil Relations
                -Mineral apatite (Ca₅F(PO₄)₃) provides P
                -Relatively stable in soil
                -Has a low mobility (1-2 cm) (therefore top dressing not effective)

            2) Plant Funtions
                -component of nucleic acids (DNA, RNA), phospholipids, coenzymes, high-energy phosphate bonds (ADP,ATP)
                -seeds are high in P

            3) Deficiency and Toxicity
                -P is mobile in plant tissure (deficiency occurs in older leaves)
                -Deficiency------dark, purplish color on older leaves
                -Exess P--------causes deficiency symptoms of An, Cu, Fe, Mn

            4) Fertilizers
                -Superphosphates (May contain F)
                                Single Superphosphate (8.6% P) CaH₄(PO₄)₂
                                Triple Superphospate (20% P)
                -Ammonium Phosphate ((NH₄)₂PO₄)  NH₄HPO₄
                  phosphoric acid (H₃PO₄) potassium phosphate, ect
                -Bonemeal
                -Absorption of available forms is influenced by pH

    C. Potassium (K)
            1) Soil Relations
                -Present in large amounts in mineral soil
                -Low in organic soil

            2)Plant Functions
                -Activator of many enzymes
                -Regulation of water movement across membranes and through stomata (Guard cell function)

            3) Deficiency and Toxicity Symptoms
                -Deficiency----- marginal necrosis, browning on leafs, older leaves more affected
                -Toxicity------- leaf tip and marginal necrosis

            4)Fertilizers
                -Potassium cloride (murate of potash) KCl
                -Potassium sulfate K₂SO₄
                -Potassium nitrate KNO₃

    D. Calcium (Ca)
            1) Soil Relations
                -present in large quantities in earth's surface (~ 4%)
                    1% in U.S. top soils
                -influences availability of other ions from soil
            2) Plant Functions
                -Component of cell walls
                -Involved in membrane function
                -Calcium pectate in middle lamela
                    Calcium pectate is immobile in tissues

            3) Deficiency and Toxicity
                -Deficiency symptoms in young leaves and new shoots (immobile)
                  stunted growth, leaf distortion, necrotic spots, shoot tip death, blossom-end rot in tomato

            4) Fertilizers
                -Agricultural meal (finely ground CaCO₃^. MgCO₃ )
                -Lime (CaCO₃) gypsum (CaSo₄)
                -Superphosphate                   Bonemeal- organic

    E. Sulfur (S)
            1) Soil Relations
                -present in mineral pyrite (FeS₂ fool's gold), sulfides (S-mineral complex) and suldates (involving SO₄^-2)
                -mostly contained in organic matter
                -acid rain provided sulfur

            2) Plant Funtions
                -component of amino acids (Methionine cysteine)
                -constituent of coenzymes and vitamins
                -responsible for pungency and flavor (Onion, garlic, mustard)

            3) Deficiency and Toxicity
                -Deficiency---------------- light green or yellowing on new growth (Sulfur is immobile in tissues)
                -Toxicity------------------ Not commonly seen

            4) Fertilizers
                -Gypsum (CaSO₄)
                -Magnesium Sulfate (MgSO₄)
                -Ammonium Sulfate ((NH₄)₂SO₄)
                -Elemental Sulfur

    F. Magnesium
            1) Soil Relations
                -presentin soil as an exchangeable cation (Mg²⁺)
                -similar to Ca²⁺ as a cation

            2) Plant Functions
                -core component of chlorophyll molecule
                -catalyst for certain enzyme activity

            3) Deficiency and Toxicity
                -Deficiency------------------ Interveinal chlorosis on mature leaves
                                                              (Mg is highly mobile in plant)
                -Toxicity--------------------- Causes deficiency symptomsof Ca, K

            4) Fertilizers
                -Dolomite ( CaCO₃ ^. MgCO₃ mixture)
                -Epsom salt (MgSO₄)
                -Magnesium Nitrate (Mg(NO₃)₂₎
 

III. MACRONUTRIENTS

    A. Iron (Fe)
            Component of cytochromes- for photosynthesis
            Essential for nitrogen fixation (Nitrate reductase) and respiration

            Deficiency------ Interveinal chlorosis on new growth
                                      Iron Chlorosis at High pH
                    Remedy- Use Iron chelates
                                    lower soil pH

                                    FeEDTA (Fe330)- Stable at pH <7.0
                                    FeEDDHA (Fe138)-Stable even when pH>7.0

                            EDTA- Ethylene diamine Tetraacetic acid
                            EDDHA- Ethylene diamine dihyroxy phenylacetic acid
 

    B. Manganese (Mn)
            Required for chlorophyll synthesis; Oxygen evolution in PHS; activates some enzyme systems

            Deficiency----- Mottled chlorosis between main veins of new leaves (Mn is imobile) Similar to iron chlorosis
            Toxicity------- Chlorosis on new growth with small, numerous dark spots
                            Deficiency occurs in high pH soils; toxicity at low pH

            Fertilizers----- MnSO₄
                                   MnEDTA (chelate) for high pH soils

    C. Boron (B)
            Involved in Carbohydrate metabolism
            Essential for flowering, pollen germination, nitrogen metabolism

            Defficiency-- New growth malformed (distorted), flowering and fruit set depressed, roots and tubers cracked
            Toxicity----- Twig dieback, fruit splitting, leaf edge burns

            Fertilizers--- Boraz (Na₂B₄O₇ ^. 10H₂O)
                                Calcium borate (CaB₄O₇ ^. 4H₂O)

    D. Zinc (Zn)
            Involved in protein synthesis, IAA (natural axin) synthesis
            Deficiency (in calcarious soil adn high pH)
                -Growth suppression, reduced internode length
                -Rosetting, interveinal chlorosis on young leaves
                    (Zn is immbile in tissues)
            Toxicity (at low pH)
                -Growth reduction, leaf chlorosis

    E. Molybdenum (Mo)
            Required for nitrate reductase activity, vitamin synthesis

            Root-nodule bacteria also requires Mo

            Defficiency (at low pH)
                    -pale-green cupped leaves (young leaves-immobile)
                    -'strap' leaf in broad leaf plants
            Toxicity
                    -Chlorosis with orange color pigmentation
            Fertilizer- Sodium Molybdate

    F. Copper (Cu)
            -Essential component of several enzymes for chlorophyll synthesis, carbohydrate metabolism.

            Defficiency---varied symptoms
                                  rosette or "witch's" broom
            Toxicity------ Chlorosis
            Fertilizer--- Copper Sulfate (CuSO₄)

    G. Chlorine (Cl)
            -Essential for photosynthetic ozygen evolution
            Defficiency-- Normally not existing but can be experimentally induced)
            Toxicity----- Never used (Cl in ubiquitous!!!)

IV. FERTILIZER CONENTRATION CALCULATIONS

    A. Analysis
            1) Commercial Analysis
                    Based on % total weights of nitrogen (N), phosphoric oxide (P₂O₅) ant potash (K₂O) in that order
                    Ex.  10-10-10 commercial analysis contains 10% N, 10% phosphoric acid, 10% potash

            2) Elemental Analysis
                    Bases on % total weights of nitrogen (N), phosphorus (P), and potassium (K), in elemental forms, arranged in that order
                    Ex. 10-10-10 elemental analysis contains 10% N, 10% P, 10% K
 

    B. Conversion of Commercial Analysis to Elemental Analysis
 

    C. Concentrations
            1. Units
                    ppm = parts per million (mg/liter)
                    mM = millimolar (1 mM = 0.001 M)
                    meq/l = milliequivalent per liter (1 meq = 0.001 eq)
 

V. HYDROPONICS

    A. Fertilizers

            1) Hoagland Solution (1950)
            2) Modifications of Hoagland solution

                 Major Nutrients    (Ca, Mg, K, N, P, S)
 

    B. Systems
            1) Aeroponics
            2) Hydroponics (closed system, open system)
            3) Aggregate Culture----Gravel, Sand, Rockwool