Fertilizer & Soil Fertilizer & Soil ManagementManagement

2002 Cotton Production Workshop2002 Cotton Production WorkshopTifton, GATifton, GA

December 10December 10--1111

Glen Harris Glen Harris -- Extension AgronomistExtension Agronomist

University Of Georgia University Of Georgia -- TiftonTifton

TopicsTopics

EconomicsEconomics

pH and LimingpH and Liming

ManganeseManganese

TroubleshootingTroubleshooting

Nitrogen and PotassiumNitrogen and Potassium

Conservation TillageConservation Tillage

Poultry LitterPoultry Litter

Black RootBlack Root

2002 Field Trials2002 Field Trials

Estimated Costs - ($/a)

LimeFertilizerDefoliantInsecticideSeedHerbicide

$ 10

$50

$16$40

$8

$35

Estimated Costs - (%)

LimeFertilizerDefoliantInsecticideSeedHerbicide

6 %

31 %

10 %25 %

6 %

22 %

Fertilization StrategyFertilization Strategy

•• Soil TestSoil Test

•• Lime to pH 6.0Lime to pH 6.0

•• Apply Recommended P & K At PlantingApply Recommended P & K At Planting

•• Approx. 80 lb N/a in Split ApplicationsApprox. 80 lb N/a in Split Applications

•• Apply 0.5 lb/a Boron Foliar at First SquareApply 0.5 lb/a Boron Foliar at First Square

•• Tissue and/or Petiole TestTissue and/or Petiole Test

Low pH ? Or Nematodes ?

Un-Reacted Lime Due To Drought ?

Too Wet To Soil Sample ?

5

5.2

5.4

5.6

5.8

6

6.2

6.4

Aug Sep Oct Nov Dec Jan Feb Mar Apr May

Month

Soil

pH

Seasonal Variation of pH

Lime (Calcium Carbonate) In Irrigation Water ?

Poultry Litter Has a Slight Liming Capacity

0-1 in0-1 in

Eff ect of poultry litter on pH . . .Eff ect of poultry litter on pH . . .

Motta et al., 1998Motta et al., 1998

w/ o lit ter

w/ lit ter

1-2 in1-2 in

2-5 in2-5 in

5-10 in5-10 in

44 55 66 77pHpH

Conservation-Tillage = SOM = CEC = Less Lime ?

Soil Test (When Dry) Account For 1. When Sampled

2. Weather (Rainfall) 3. Previous Crop 4. Poultry Litter

5. When Limed Last

Manganese For CottonManganese For Cotton

•• UGA Dropped RecommendationUGA Dropped Recommendation

•• MnMn Deficiency on Cotton RareDeficiency on Cotton Rare

•• Maintain Soil Test Maintain Soil Test Mn Mn by pHby pH

•• Expensive to Build ST Expensive to Build ST Mn Mn All at OnceAll at Once

•• Look For Borderline FieldsLook For Borderline Fields

•• Consider Starter or Foliar Consider Starter or Foliar MnMn

•• Tissue Test To Confirm ProblemTissue Test To Confirm Problem

0

2

4

6

8

10

12

14

16

18

5.6 5.7 5.8 5.9 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 7 7.1

Soil pH

Soil

Tes

t M

n (l

b/a)

Recommended Soil Test Mn with Different pH

TroubleshootingTroubleshooting

Likely Culprits Likely Culprits

•• Low pH Low pH

•• NitrogenNitrogen

•• PotassiumPotassium

•• SulfurSulfur

•• Boron ?Boron ?

Troubleshooting SamplingTroubleshooting Sampling

Prior To First BloomPrior To First Bloom

Soil and Tissue Sample Soil and Tissue Sample

“Good” & “Bad” “Good” & “Bad”

After First BloomAfter First Bloom

Soil, Tissue and Petiole Soil, Tissue and Petiole

Good” & “Bad” Good” & “Bad”

Nitrogen ManagementNitrogen Management

•• By Yield GoalBy Yield Goal

•• DrylandDryland vs. Irrigatedvs. Irrigated

•• Split ApplicationsSplit Applications

•• Sidedress Sidedress MaterialsMaterials

Potassium ManagementPotassium Management

•• All At PlantingAll At Planting

•• Anticipate ProblemsAnticipate Problems

•• Foliar vs. Foliar vs. Sidedress Sidedress ??

Results :1998Results :1998

•• Significant Significant

InteractionInteraction

•• AP/+F =AP/+F =

Best TreatmentBest Treatment

15931685

1524 1515

0

300

600

900

1200

1500

1800

AP/-F AP/+F SA/-F SA/+F

Foliar FertilizationFoliar Fertilization

•• Rescue vs. High YieldRescue vs. High Yield

•• High Boy vs. PlaneHigh Boy vs. Plane

•• Alone or With InsecticideAlone or With Insecticide

•• Source, Rates and TimingSource, Rates and Timing

•• N, K, B (maybe Zn or N, K, B (maybe Zn or MnMn))

•• Not P or Ca or Snake OilsNot P or Ca or Snake Oils

Conservation Tillage - FAQs

How Important Is A Good Start ? Should I Soil Sample Differently ? How Can Lime Work ? Can You Get Too Much Residue ? Should I Fertilize My Cover Crop ? Should I Adjust My N Rate on Cotton ? Should I Use A Starter Fertilizer Can I Use Poultry Litter ?

Nutrient stratification . . .Nutrient stratification . . .

P and K become horizontally bandedP and K become horizontally banded

0 50 100 150

Molboard

Chisel

No-till 0-5 cm

5-10 cm

10-15 cm

15-20 cm

(Karlen et al., 1991)

Soil P distribution af ter 11 years of t illage

P (mg/kg)

0 50 100 150 200 250

Molboard

Chisel

No-till0-2.5 cm

2.5-7.5 cm

7.5-15 cm

15-22.5 cm

22.5-30 cm

(Motta et al., 2000)

K distribution af ter 17 years of ti llage

K (mg/ kg)

Nitrogen Management . . .Nitrogen Management . . .Nitrogen Management . . .

N and cover cropsN and cover cropsN and cover crops

C : N RatioC : N RatioC : N Ratio

N

Available

NN

AvailableAvailable

N

Not Available

NN

Not AvailableNot Available

10:110:110:1 20:120:120:1 40:140:140:1

MineralizationMineralizationMineralization I mmobilizationI mmobilizationI mmobilization

Poultry Litter on CottonPoultry Litter on Cotton

•• 2 ton/a + 50 lb N/a 2 ton/a + 50 lb N/a SidedressSidedress

Basically = P Based PlanBasically = P Based Plan

•• 3 3 -- 4 ton/a If 4 ton/a If Blackroot Blackroot

•• Phosphorous IssuePhosphorous Issue

“Black Root” Update“Black Root” Update

First Observed in 1997 First Observed in 1997

Isolated to Poorly DrainedIsolated to Poorly Drained

Flatwoods Flatwoods Soils Soils

Disease Organism Never Disease Organism Never

Isolated Isolated

Gary Gary Gascho Gascho (1998) -(1998) -

Chloride Toxicity ? Chloride Toxicity ?

2002 Field Trials2002 Field Trials

Helena - Foliar N Helena - Foliar N

Agrotain Agrotain - UAN - UAN vsvs. Urea. Urea

GPFES - GPFES - Sidedress vsSidedress vs. Foliar K. Foliar K

AgriAgri-SC - Laurel sulfate-SC - Laurel sulfate

Stoller Stoller - Load- Load

GoemarGoemar - BM 86 - BM 86

Good Luck in 2003 !