Transcript Plant Nutrients

Horticulture 1
Ag. 514
Sources of Plant Nutrients
Water
 90% of a plants weight
Water
 Photosynthesis (PSN) uses water.
Water
 Plant uptake is via water from
the soil
 What type of cells uptake water
and nutrients from the soil?

xylem
 Transpiration creates 90-95 % of
a plants water loss….
 What is transpiration?

Water vapor exiting through leaf
stomata (pores).
Light
 Must be present for green plants to manufacture food.
 Light requirements vary between plant types.
Annuals like
Marigolds like
6 to 8 hours of
sun
Roses like 10 to 12 hours of sun
to grow properly.
Corn likes 12 to 16
hours if it can get it!
Light
 Photoperiodism
 Plant growth responses to different lengths of night and
day.

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Long day, short day or indifferent
Plants flower according to day length.
Poinsettias are short day plants;
manipulating the time of darkness
makes them flower sooner.
Photoperiodism (cont’d.)
Dianthus is a long day plant;
it needs long days of light to
initiate flower set.
Cucumbers are indifferent;
they will set flowers when
the plant reaches maturity.
Air
 Temperature affects plant growth.
 Plant types have different temperature preferences.
 Hardy plants are more tolerant of cold air and frost
 Tender plants are intolerant of cold air and frost
 Below freezing temperatures halt growth or kill
plants.
Gases and Air Particles.
 Carbon dioxide is vital to plants for food production.
 Increases crop yields.
 Sulfur dioxide damages crops by reducing growth or killing plants.
Soil
 Plants receive nutrients from water in the soil.
 Nutrients come from decayed plant and animal matter and the mineral
content of the soil.
 Chemical interactions from oxygen in soil fix nitrogen and make this
important nutrient available to plants through water in the soil.
Primary and Secondary Nutrients
AKA: Macronutrients
 Primary (Essential)Nutrients
 Nitrogen (N)
 Phosphorous (P)
 Potassium (K)
 Secondary Nutrients
 Calcium (Ca)
 Magnesium (Mg)
 Sulfur (S)
Micronutrients (needed in small amounts).
 Micronutrients
 Boron (B)
 Chlorine (Cl)
 Copper (Cu)
 Iron (Fe)
 Manganese (Mn)
 Molybdenum (Mo)
 Zinc
 Needed in smaller amounts (trace elements).
 Aluminum (Al)
 Fluorine (F)
 Nickel (Ni)
 Sodium (Na)
 Primary nutrients must be present in
 Secondary nutrients must be present in
amounts.
 Micronutrients are necessary, but needed in
amounts.
amounts.
Factors that Influence Use of Fertilizers
 Rooting characteristics of plant species.
 Fibrous roots readily absorb liquid fertilizers
 Tap roots are slower to absorb and require granular
fertilizers that remain in the soil for a longer period
 Nutrient demands of plants during different stages of
plant’s growth.
Germination
Vegetative Growth
Reproductive
 Physical and chemical characteristics of the soil and the fertilizer applied.
 Soil moisture availability to plants.
 Irrigation system type.
Nitrogen – Commercially Available in Four
Forms
 Nitrate of Soda
 NaNO3
 Highly soluble
 Lowers soil acidity
 16% nitrogen
 Ammonium nitrate
 NH4NO3
 Not as soluble
 Gradually available
 33% nitrogen
 Ammonium sulfate
 (NH4)2SO4
 More acidic
 Gradually available
 21% nitrogen
 Urea
 Organic nitrogen
 More gradually available
than inorganic nitrogen
 38% nitrogen
Nitrogen Deficiency
 Slow growing plants
 Stunted plants
 Chlorosis in older leaves
 Chlorosis – production of
insufficient chlorophyll
 Copper color or “firing” in
older leaves
Phosphorus – Commercially Available in Four
Forms
 Superphosphate (20%)
 Treble (or double) superphosphate (46%)
 Rock phosphate (25-35%)
 Ammonium phosphate (48%)
Phosphorus Deficiency
 Purple coloring on
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


undersurface of leaves
Reduced flower, fruit and
seed production
Susceptibility to cold
Susceptibility to disease
Poor quality fruit and seeds
Potassium-Commercially Available in Three
Forms
 Muriate of potash (Potassium
chloride) (60%)
 Sulfate of potash (49%)
 Nitrate of potash (44% K / 13% N)
Freshly mined potash –
naturaly occurring
potassium salts
Potassium Deficiency
 Burn or scorching around
leaf margins (more severe
with older leaves)
Definition of Fertilizer
 Material used to provide plants with the nutrients they need.
 Added to growing medium.
 Absorbed by the roots of plants.
Application
 Added to growing medium.
 Slow release
 granular
 Leaf spray (foliar)
 Applied to soil for root uptake.
Forms
 Solid
 Liquid
 Gaseous (anhydrous ammonia)
 Plants can be damaged by too
much, too little, or the wrong
fertilizer.
Definitions
 Elemental fertilizer.
 Provides one plant nutrient.
 Complete fertilizer.
 Contains all three primary nutrients.
 May have selected micronutrients.
 Incomplete fertilizer.
 Lacks one of the primary nutrients.
 A guaranteed analysis of 23-6-0 would be an incomplete fertilizer.
 Active ingredient
 Total percentage of nutrients applied.
 Inert ingredient.
 Filler material as base allowing application of the fertilizer.
 Fertilizer analysis
 Percentage by weight
 Three number designation
 Composition of active ingredients in fertilizer formulation – 16-4-8
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
16% nitrogen
4% phosphorous
8% potash (potassium)
Total 16-4-8=28% active ingredients
100%-28%= 72% inert ingredients.
 How many pounds of each element would a 50lb. bag of fertilizer with a
guaranteed analysis of 17-8-3 have?