Understanding the Role of Understanding the Role of Fertilizer and WaterFertilizer and Water

Understanding the Role of Understanding the Role of Fertilizer and WaterFertilizer and Water

David Wm. ReedDavid Wm. ReedDepartment of Horticultural SciencesDepartment of Horticultural Sciences

Texas A&M UniversityTexas A&M University

17 Essential Elements17 Essential Elements

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Supplied Naturally (by HSupplied Naturally (by H220, O0, O22, CO, CO22))

C, H, OC, H, O

MacronutrientsMacronutrientsN, P, K, Ca, Mg, SN, P, K, Ca, Mg, S

Micronutrients or Trace ElementsMicronutrients or Trace ElementsFe, Cu, Mn, Zn, B, Mo, Cl, NiFe, Cu, Mn, Zn, B, Mo, Cl, Ni

Where Do All the Nutrients Come From?Where Do All the Nutrients Come From?   NN PP KK CaCa MgMg SS FeFe BB Other MicroOther Micro

Incorporated into Soil or Growing Medium - Pre-PlantingIncorporated into Soil or Growing Medium - Pre-Planting

complete fertilizercomplete fertilizer XX XX XX       ??         

superphosphatesuperphosphate    XX    XX    XX         

dolomitic limedolomitic lime          XX XX            

gypsumgypsum          XX    XX         

iron sulfateiron sulfate                XX XX      

micronutrient mixmicronutrient mix                   XX XX allall

Supplied Post-Planting as Granular, Liquid or Slow-Release ApplicationSupplied Post-Planting as Granular, Liquid or Slow-Release Application

complete fertilizercomplete fertilizer XX XX XX       ??         

Epsom saltEpsom salt             XX XX         

soluble micronutr.soluble micronutr.                   XX XX allall

some pesticidessome pesticides                   XX    Cu,Mn,ZnCu,Mn,Zn

irrigation water ppmirrigation water ppm          >3-5>3-5 >1>1       0.3-1.50.3-1.5   

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Water: Water: Soluble Salts (EC), pH & AlkalinitySoluble Salts (EC), pH & Alkalinity

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Collect water sampleCollect water sampleMeters UsedMeters Used

•pH: pH: pH meterpH meter•Soluble Salts or EC: Soluble Salts or EC: conductivity meterconductivity meter•Alkalinity: Alkalinity: alkalinity test kit or paperalkalinity test kit or paper

Compare reading to Interpretation TableCompare reading to Interpretation Table

Meters UsedMeters Used2

ECECpHpH

alkalinity kitalkalinity kit

Meters UsedMeters Used2

CombinationCombinationEC & pHEC & pH

MeterMeter

WaterWater Soluble Salts or Soluble Salts or

Electrical Conductivity (EC)Electrical Conductivity (EC)

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Relative Hazard

None Little Moderate High Severe

Electrical Conductivity

dS/m or mmhos/cm

0.2 <0.7 0.7-2 2-3 >3

 Soluble Saltsppm

140 <490 490 - 1400 1400 - 2100 >2100

WaterWater AlkalinityAlkalinity

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Recommended Alkalinity LevelsMinimum Maximum

ppm meq/l ppm meq/l

Plugs and/or seedlings 38 0.75 66 1.3

Small pots and shallow flats 38 0.75 86 1.7

4" to 5" pots and deep flats 38 0.75 106 2.1

6” pots and long term crops 63 1.25 131 2.6

Soil/MediaSoil/Media Soluble Salts (EC) & pHSoluble Salts (EC) & pH

5 & 6

Collect soil/medium sample below surfaceCollect soil/medium sample below surfaceExtract with water (1:2 dilution)Extract with water (1:2 dilution)FilterFilterMeters UsedMeters Used

•pH: pH: pH meterpH meter•Soluble Salts or EC: Soluble Salts or EC: conductivity meterconductivity meter

Compare reading to Interpretation TableCompare reading to Interpretation Table

Soil/MediaSoil/Media pH pH

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SME 1:2 or 1:5 Dilution  

Extract Slurry Extract Slurry Pour-Through

Optimum pH 5.5 - 6.55.4 - 6.2

5.5 - 6.5 5.4 - 6.2 5.5 - 6.5

Soil/MediaSoil/MediaSoluble Salts (EC)Soluble Salts (EC)

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Electrical Conductivity (EC) dS/m or mmho/cm

SME 1:2 Dilution 1:5 Dilution Pour-Through

Established plants 2.0-3.0 0.8-1.2 0.3-0.6 3.0-5.0

Seedlings, plugs 1.0-2.0 0.5-0.9 ? ?

Graphical Tracking pH and ECGraphical Tracking pH and EC

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0

1

2

3

4

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Weeks after Planting

EC

(d

S/c

m)

Graphical Tracking of ECGraphical Tracking of EC

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Selecting a Fertilizer Based on the Selecting a Fertilizer Based on the Form of NitrogenForm of Nitrogen

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Nitrogen exists in two formsNitrogen exists in two formsAmmoniacal (NHAmmoniacal (NH44

++, urea), urea)Nitrate (NONitrate (NO33

--))

Nitrogen form used affectsNitrogen form used affectsType of growthType of growthType fertilizer, acid vs. basicType fertilizer, acid vs. basicpH of the soil or growing mediumpH of the soil or growing medium

Selecting a Fertilizer Based on the Selecting a Fertilizer Based on the Form of NitrogenForm of Nitrogen

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Form of Nitrogen Influences Type Growth and is SeasonalForm of Nitrogen Influences Type Growth and is Seasonal

Nitrogen FormNitrogen Form Type GrowthType Growth Used ForUsed For

High AmmoniacalHigh Ammoniacal

(>25%)(>25%)

•lush growthlush growth•larger leaveslarger leaves•longer stemslonger stems

•foliage plantsfoliage plants•flowering plants earlyflowering plants early•warmer & summerwarmer & summer

High NitrateHigh Nitrate

(>75%)(>75%)

•hardy planthardy plant•compact growthcompact growth

•flowering plants flowering plants finishingfinishing•cooler & wintercooler & winter

Selecting a Fertilizer Based on the Selecting a Fertilizer Based on the Form of NitrogenForm of Nitrogen

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Form of Nitrogen Influences Soil/Medium pHForm of Nitrogen Influences Soil/Medium pH

Nitrogen FormNitrogen Form Type FertilizerType Fertilizer Soil/Medium ReactionSoil/Medium Reaction

High AmmoniacalHigh Ammoniacal

(>25%)(>25%)acidacid

pH decreases &pH decreases &

becomes more acidbecomes more acid

High NitrateHigh Nitrate

(>75%)(>75%)basicbasic

pH increases &pH increases &

becomes more basicbecomes more basic

Selecting a Fertilizer Based on the Form of NitrogenSelecting a Fertilizer Based on the Form of Nitrogen10

Acid versus Basic FertilizersAcid versus Basic FertilizersFertilizerFertilizer % NH4% NH4 / / % NO3% NO3 PotentialPotential

AcidityAcidityPotentialPotentialBasicityBasicity

21-7-7 acid21-7-7 acid 100100 / 0 / 0 15601560 0 0 

20-18-1820-18-18 7373 / 27 / 27 710710 0 0 

15-15-1515-15-15 5252 / 48 / 48 261261 0 0 

20-10-2020-10-20 3838 / 48 / 48 393393 0 0 

20-0-2020-0-20 2525 / 75 / 75 4040 00

15-5-15 15-5-15 28 / 28 / 7272   00 135135

15-0-1515-0-15 13 / 13 / 8787 0 0  319319

15.5-0-0 Ca nitrate15.5-0-0 Ca nitrate 6 / 6 / 9494 0 0  400400

13-0-44 K nitrate13-0-44 K nitrate 0 / 0 / 100100 0 0  460460

Fertilizer Label Lists Potential AcidityFertilizer Label Lists Potential Acidity10

Label Fertilizer Analysis

Fertilizer Label Lists Potential AcidityFertilizer Label Lists Potential Acidity

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Micronutrients in Acid Vs. Alkaline SoilMicronutrients in Acid Vs. Alkaline Soil(especially heavy metals: Fe, Mn, Zn, Cu)(especially heavy metals: Fe, Mn, Zn, Cu)

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Selection of Heavy Metal Carriers based on Soil pHSelection of Heavy Metal Carriers based on Soil pH

Iron CarrierIron Carrier Acid SoilAcid Soil Alkaline SoilAlkaline Soil

SulfatesSulfates effectiveeffective not very effectivenot very effective

ChelatesChelateseffective, but effective, but

expensive so why use.expensive so why use.most effectivemost effective

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Which Chelate to Use?Which Chelate to Use?Which Chelate to Use?Which Chelate to Use?1111

Which Chelate to Use?Which Chelate to Use?

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Highest pH Still EffectiveHighest pH Still Effective ChelateChelate

66lignosulfonate, citrate, lignosulfonate, citrate,

HEDTAHEDTA

6.56.5EDTAEDTA

7.57.5 DTPA (330)DTPA (330)

any pHany pHEDDHA (138)EDDHA (138)

Fertilizer Label - Micronutrient CarriersFertilizer Label - Micronutrient Carriers1111

Rose Rootstocks Tolerance to AlkalineRose Rootstocks Tolerance to Alkaline SoilSoil12

Rose species/cultivarRose species/cultivar Chlorosis RatingChlorosis Rating(5=green to 1=yellow)(5=green to 1=yellow)

R. caninaR. canina 5.05.0

R. manettiiR. manettii 4.94.9

R. odorataR. odorata 4.84.8

R. sp. “R. sp. “Mexican”Mexican” 4.84.8

R. fortunianaR. fortuniana 4.44.4

R. multiflora R. multiflora 'Dan Whiteside''Dan Whiteside' 2.72.7

R. multifloraR. multiflora ‘Brooks 56' ‘Brooks 56' 2.72.7

R. multifloraR. multiflora 74-3 74-3 dieddied

R. R. 'Dr Huey''Dr Huey' dieddied

Rose Rootstocks Tolerance to AlkalineRose Rootstocks Tolerance to Alkaline SoilSoil

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EarthKindEarthKindTMTM Landscape Roses Landscape Roses(http://aggie-horticulture.tamu.edu/earthkindrose/index.html)(http://aggie-horticulture.tamu.edu/earthkindrose/index.html)

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EarthKindEarthKindTMTM Landscape Roses Landscape Roses13

CultivarCultivar Flower ColorFlower Color Flower TypeFlower Type Blooming PeriodBlooming Period Ht x Wd (feet)Ht x Wd (feet) CategoryCategory

Ground CoversGround Covers

Sea FoamSea Foam creamy whitecreamy white doubledouble April-NovemberApril-November 2 x 62 x 6 shrubshrub

Dwarf ShrubsDwarf Shrubs

Marie DalyMarie Daly PinkPink semi-doublesemi-double April-NovemberApril-November 3 x 33 x 3 polyanthapolyantha

The FairyThe Fairy light pinklight pink doubledouble April-NovemberApril-November 3 x 43 x 4 polyanthapolyantha

Small ShrubsSmall Shrubs

Caldwell PinkCaldwell Pink lilac pinklilac pink doubledouble May- NovemberMay- November 4 x 44 x 4 foundfound

Easy GoingEasy Going yellowyellow doubledouble April-NovemberApril-November 4 x 44 x 4 floribundafloribunda

Knock OutKnock Out cherry redcherry red semi-doublesemi-double April-NovemberApril-November 4 x 44 x 4 shrubshrub

Livin' EasyLivin' Easy apricot-orangeapricot-orange doubledouble April-NovemberApril-November 4 x 44 x 4 floribundafloribunda

Perli d'OrPerli d'Or peachpeach pomponpompon April-NovemberApril-November 4 x 44 x 4 polyanthapolyantha

Medium ShrubsMedium Shrubs

Belinda's DreamBelinda's Dream PinkPink doubledouble April-NovemberApril-November 5 x 55 x 5 shrubshrub

Climbing PinkieClimbing Pinkie pinkpink semi-doublesemi-double April-NovemberApril-November 5 x 75 x 7 polyanthapolyantha

Else PoulsenElse Poulsen pinkpink semi-doublesemi-double April-NovemberApril-November 5 x 55 x 5 floribundafloribunda

Katy Road PinkKaty Road Pink pinkpink semi-doublesemi-double April-NovemberApril-November 5 x 45 x 4 foundfound

Mutabilis Butterfly RoseMutabilis Butterfly Rose yellow, pink, yellow, pink, crimsoncrimson

singlesingle April-NovemberApril-November 6 x 66 x 6 ChinaChina

Belinda’s DreamBelinda’s Dream(developed by Dr. Robert Basye)(developed by Dr. Robert Basye)

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