CRSS 2830CRSS 2830

Lesson 8Lesson 8

FertilizationFertilization

PLANT NUTRIENTSPLANT NUTRIENTS

• 16 essential nutrients16 essential nutrients

PLANT NUTRIENTSPLANT NUTRIENTS• Carbon, hydrogen and oxygen Carbon, hydrogen and oxygen

obtained from water and airobtained from water and air

• Remaining 13 divided into three Remaining 13 divided into three groups:groups:

PLANT NUTRIENTSPLANT NUTRIENTS• Three Groups:Three Groups:

– Primary: nitrogen, phosphorus, potassiumPrimary: nitrogen, phosphorus, potassium– Secondary: Calcium, magnesium, and sulfurSecondary: Calcium, magnesium, and sulfur– Micronutrients: Iron, manganese copper, Micronutrients: Iron, manganese copper,

boron, zinc, chlorine, molybdenumboron, zinc, chlorine, molybdenum

FERTILIZERSFERTILIZERS

• Complete fertilizer = N-P-KComplete fertilizer = N-P-K

• Fertilizer grade = minimum Fertilizer grade = minimum guaranteed analysisguaranteed analysis

FERTILIZERSFERTILIZERS

• 20-5-10 = 20 %N, 5% P2O5, 10% 20-5-10 = 20 %N, 5% P2O5, 10% K2OK2O

• Therefore, a 50 pound bag would Therefore, a 50 pound bag would contain...contain...– N = 10 lbsN = 10 lbs– P2O5 = 2.5 lbsP2O5 = 2.5 lbs– K2O = 5 lbs K2O = 5 lbs

FERTILIZERSFERTILIZERS

• Fertilizer RatioFertilizer Ratio– 20-5-10 = 4-1-2 ratio20-5-10 = 4-1-2 ratio– 30-10-10 = 3-1-1 ratio30-10-10 = 3-1-1 ratio– 10-5-20 = 2-1-4 ratio10-5-20 = 2-1-4 ratio

FERTILIZERSFERTILIZERS• How much 20-5-10 must be applied to

achieve 1 lb of N/1000 sq. ft.? How much 20-5-10 should be applied to a 6000 sq. ft. lawn?– 1/.20 = 5 lbs of 20-5-10/1000 sq. ft. – 5 lbs./1000 sq. ft. X 6 = 30 lbs of 20-5-10

• (Not 6 lbs of 20-5-10)

NITROGENNITROGEN• Used in greatest amountsUsed in greatest amounts

• Most fertility programs based on Most fertility programs based on nitrogennitrogen

• Too much will encourage disease and Too much will encourage disease and reduce root growthreduce root growth

012345678

0 0.5 2.5 6 10 16 24

TURF QUALITY AND ROOT GROWTH TURF QUALITY AND ROOT GROWTH AFFECTED BY NITROGEN RATEAFFECTED BY NITROGEN RATE

QU

AL

ITY

RA

TIN

GQ

UA

LIT

Y R

AT

ING

Lbs. N / 1000 sq. ft. / YearLbs. N / 1000 sq. ft. / Year

3

2

1

0 RO

OT

WE

IGH

T (g

/ sq

. dm

RO

OT

WE

IGH

T (g

/ sq

. dm

)

QUALITYROOT WEIGHT

NITROGENNITROGEN

• Types of Nitrogen FertilizersTypes of Nitrogen Fertilizers

– Soluble or fast releaseSoluble or fast release

– Insoluble or slow releaseInsoluble or slow release

NITROGENNITROGEN

• Soluble FertilizersSoluble Fertilizers– Ammonium nitrate 33%Ammonium nitrate 33%– Ammonium sulfate 21%Ammonium sulfate 21%– Potassium nitrate 13%Potassium nitrate 13%– Urea 45%Urea 45%

NITROGENNITROGEN• Insoluble FertilizersInsoluble Fertilizers

– IBDU (isobutylidenediurea) 31 %IBDU (isobutylidenediurea) 31 %– UF (ureaformaldhyde) 38 %UF (ureaformaldhyde) 38 %– Methylene urea 38 %Methylene urea 38 %– Sulfur coated urea 32 % Sulfur coated urea 32 % – Poly coated urea 39-44%Poly coated urea 39-44%– Natural organics 3 - 11% (cow, chicken Natural organics 3 - 11% (cow, chicken

manure, dried blood, etc.)manure, dried blood, etc.)

PHOSPHORUSPHOSPHORUS

• Critical at establishmentCritical at establishment

• Not prone to leachingNot prone to leaching

• Promotes rootingPromotes rooting

POTASSIUMPOTASSIUM

• Important for stress toleranceImportant for stress tolerance– (heat, cold, drought, (heat, cold, drought, traffic, diseases, etc)traffic, diseases, etc)

• Will leachWill leach

IRONIRON

• Most often applied micronutrientMost often applied micronutrient

WHEN TO FERTILIZEWHEN TO FERTILIZE• Beginning or during favorable growth Beginning or during favorable growth

conditionsconditions

• Cool seasonCool season – Spring (light)Spring (light)– Late summer/early fallLate summer/early fall– Late fall Late fall – Rarely summerRarely summer

WHEN TO FERTILIZEWHEN TO FERTILIZE

• Warm seasonWarm season– Late springLate spring– SummerSummer– Possibly early spring and late summerPossibly early spring and late summer

HOW MUCH TO APPLYHOW MUCH TO APPLY

• Depends on:Depends on:– Species (refer to book)Species (refer to book)– SeasonSeason– Type of fertilizerType of fertilizer– Environment Environment (shade vs. sun)(shade vs. sun)

APPLICATION METHODSAPPLICATION METHODS

• GranularGranular• LiquidLiquid• (same to the plant)(same to the plant)

GRANULAR APPLICATIONGRANULAR APPLICATION

• rotaryrotary

• drop-type drop-type

• (Apply to dry turf and water in)(Apply to dry turf and water in)

LIQUID APPLICATIONLIQUID APPLICATION

• drench (3 to 5 gals/1000 sq. ft.)drench (3 to 5 gals/1000 sq. ft.)

• foliar (< 1 gal/1000 sq. ft.)foliar (< 1 gal/1000 sq. ft.)

• fertigation (applied via irrigation fertigation (applied via irrigation systemsystem))