Objectives by 2i48203

VIEWS: 10 PAGES: 13

									      Objectives
   To understand the importance of fertilizers
    and pH
   To distinguish fertilizer types
   To calculate fertilizer rates for their home
    gardens

   Apply fertility concepts to a vegetable
    experiment
Soil Fertility and Fertilizers
   What is a fertilizer?
       Definition - a material added to the
        garden that supplies essential nutrients
        plants need for vegetative and
        reproductive growth.
   Why are fertilizers important?
       Build-up - increasing the level of minerals
        and OM in the soil.
       Maintenance - replenishing nutrients lost
        through leaching, removal during plant
        growth, and harvest
Macronutrients
   Nitrogen (N)
       Most mobile nutrient; subject to loss by leaching
       Used to form proteins and pigments (chlorophyll)
   Phosphorus (P)
       Immobile nutrient; must be incorporated into soil
       Important for energy transfer (ATP) in plants
   Potassium (K)
       Immobile nutrient; must be incorporated also
       Important for cell wall formation and cell liquid balance
        Fertilizers and pH
   Optimum soil pH is
    plant species
    dependent
       Most plants will grow
        well at pH 6.2-6.8         Slightly     Moderately     Very
       IL soils slightly acidic   Tolerant     Tolerant       Tolerant
        - 5.8-6.8                  (pH 6.5-6.8) (pH 5.5-6.8)   (pH 5.0-6.8)
                                   Asparagus    Bean           Potato
                                   Beet         Carrot         Rhubarb
                                   Broccoli     Corn           Sweet
                                   Cabbage      Cucumber       Potato
                                                               Watermelon
Fertilizers and pH
   pH influences nutrient availability
       Determines nutrient form in soil
       How strongly nutrients are bound to soil particles
   Nutrients deficient in acid soils
       Ca, P, Mg, Mo
   Nutrients deficient in alkaline soils
       Cu, Fe, Mn
Nutrient availability by pH
  Adjusting pH
     Lime replaces H+ ions with Ca2+ ions
     Amount applied depends on soil type
      and pH change desired

Desired pH ∆   Sand            Loam              Silt Loam        Clay Loam
               ----------------------Lbs/Acre of limestone------------------------
4.5  6.5      2200            5800              7000             8400
5.5  6.5      1200            3400              4000             4600
6.0  6.5      600             1800              2200             2400
Types of Fertilizers
   By form
       Synthetic - Miracle Grow®, Osmocote®
       Organic - manure, fish meal, bone meal
   By physical state
       Solid - manure, compost, granulated
       Liquid - seaweed extract, anhydrous
   By rate of release
       Fast release - mostly synthetic types
       Slow release - carbon-based (organic),
         Osmocote®
Fertilizer Grade
   Definition -
    guaranteed
    minimum % of total
    N, available P, and
    water-soluble K
       10-10-5 =
            10% total nitrogen
            10% available
             phosphoric acid
             5% water-soluble
             potash
Determining Fertilizer Needs
   Soil Testing
       Must collect representative samples
       Professional labs analyze soil for a fee
            Also provide fertilizer recommendations
       Home testing kits available
       Indicates levels of P, K, Mg, pH, and CEC
       Poor indicator of nitrogen levels due to
            Leaching losses
            Mineralization
Calculating Fertilizer Rates
   Measure area to be fertilized
       10ft x 40ft = 400ft2
   Determine amount
    applied/Acre using soil test
    recommendations
       Need - 100lb/A total N
               100lb/A available P
               50lb/A water-soluble K
    Calculating Fertilizer Rates…
   Use fertilizer grade to convert amount of
    nutrients/A to amount fertilizer/A
       100lbs/A total N = 1000lbs fertilizer/A
             .10
       100lbs/A available P = 1000lbs fertilizer/A
             .10
       50lbs/A water-soluble K = 1000lbs fertilizer/A
             .05
Calculating Fertilizer Rates…
   Determine amount fertilizer for your
    garden space - 400ft2
       43,560 ft2 in an acre
       Set up a proportion
       1000lbs fertilizer = x__
          43,560 ft2            400ft2
       x = 9.18 lbs fertilizer
       9.18 lbs x 454.6g/lb = 4,172g fertilizer!

								
To top