CRSS 2830 Lesson 8 Fertilization

PLANT NUTRIENTS 16 essential nutrients

Carbon, hydrogen and oxygen obtained from water and airCarbon, hydrogen and oxygen obtained from water and air Remaining 13 divided into three groups:Remaining 13 divided into three groups:

PLANT NUTRIENTS Three Groups:Three Groups: –Primary: nitrogen, phosphorus, potassium –Secondary: Calcium, magnesium, and sulfur –Micronutrients: Iron, manganese copper, boron, zinc, chlorine, molybdenum

FERTILIZERS Complete fertilizer = N-P-KComplete fertilizer = N-P-K Fertilizer grade = minimum guaranteed analysis

FERTILIZERS = 20 %N, 5% P2O5, 10% K2O = 20 %N, 5% P2O5, 10% K2O Therefore, a 50 pound bag would contain...Therefore, a 50 pound bag would contain... –N = 10 lbs –P2O5 = 2.5 lbs –K2O = 5 lbs

FERTILIZERS Fertilizer RatioFertilizer Ratio – = ratio – = ratio – = ratio

FERTILIZERS How much must be applied to achieve 1 lb of N/1000 sq. ft.? How much should be applied to a 6000 sq. ft. lawn? –1/.20 = 5 lbs of /1000 sq. ft. –5 lbs./1000 sq. ft. X 6 = 30 lbs of (Not 6 lbs of )

NITROGEN Used in greatest amountsUsed in greatest amounts Most fertility programs based on nitrogenMost fertility programs based on nitrogen Too much will encourage disease and reduce root growthToo much will encourage disease and reduce root growth

TURF QUALITY AND ROOT GROWTH AFFECTED BY NITROGEN RATE QUALITY RATING Lbs. N / 1000 sq. ft. / Year ROOT WEIGHT (g / sq. dm ROOT WEIGHT (g / sq. dm) QUALITY ROOT WEIGHT

NITROGEN Types of Nitrogen FertilizersTypes of Nitrogen Fertilizers –Soluble or fast release –Insoluble or slow release

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

NITROGEN Insoluble FertilizersInsoluble Fertilizers –IBDU (isobutylidenediurea) 31 % –UF (ureaformaldhyde) 38 % –Methylene urea 38 % –Sulfur coated urea 32 % –Poly coated urea 39-44% –Natural organics % (cow, chicken manure, dried blood, etc.)

PHOSPHORUS Critical at establishment Not prone to leachingNot prone to leaching Promotes rootingPromotes rooting

POTASSIUM Important for stress toleranceImportant for stress tolerance –(heat, cold, drought, traffic, diseases, etc) traffic, diseases, etc) Will leachWill leach

IRON Most often applied micronutrientMost often applied micronutrient

WHEN TO FERTILIZE Beginning or during favorable growth conditionsBeginning or during favorable growth conditions Cool seasonCool season –Spring (light) –Late summer/early fall –Late fall –Rarely summer

WHEN TO FERTILIZE WarmWarm season –Late –Late spring –Summer –Possibly –Possibly early spring and late summer

HOW MUCH TO APPLY Depends on:Depends on: –Species (refer to book) –Season –Type of fertilizer –Environment (shade vs. sun) (shade vs. sun)

APPLICATION METHODS GranularGranular LiquidLiquid (same to the plant)(same to the plant)

GRANULAR APPLICATION rotary rotary drop-typedrop-type (Apply to dry turf and water in) (Apply to dry turf and water in)

LIQUID 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 system)fertigation (applied via irrigation system)