Renewed Interest in Blueberry N Renewed Interest in Blueberry N Sources for North Carolina Sources for North Carolina

ProductionProduction

David H. HardyDavid H. Hardy

NCDA&CS Agronomic NCDA&CS Agronomic DivisionDivision

SERA 6 Annual Meeting

June 14, 2010

Today’s PresentationToday’s Presentation General overview of productionGeneral overview of production

Standard fertilizer program Standard fertilizer program

Fertility interests to pursueFertility interests to pursue

Challenges in blueberry fertilityChallenges in blueberry fertility

Overview of 2009 studyOverview of 2009 study

Future workFuture work

N.C. Blueberries

4,200 acres $3.7 million in 2007 4th largest producer in U.S. 5th highest yield in U.S.—

5430 lb/A

N.C. Highbush & Rabbiteye

— 80% Highbush

concentrated in Bladen, Pender Duplin, & Sampson counties

Preferred Soil pH Levels

Highbush 4.0–5.0 Rabbiteye 4.5–5.3

Dr. George Cummings, 2005 N.C. Blueberry Council Proceedings

Soil types in southeastern NC may vary greatly

and have a major fertility impact.

Nitrogen and phosphorusare the two

most importantnutrients.

The micronutrient copper is often deficient.

Standard Fertilizer ProgramStandard Fertilizer Program

14-28-14 @ bud break about14-28-14 @ bud break about mid-March mid-March– 100 to 150 lb per acre100 to 150 lb per acre

14-28-14 in early May14-28-14 in early May– 75 lb per acre75 lb per acre

18-46-0 (DAP) in late July or early 18-46-0 (DAP) in late July or early AugustAugust– 50 lb per acre50 lb per acre

Standard Fertilizer ProgramStandard Fertilizer Program

Developed from work of CummingsDeveloped from work of Cummings

– Older varietiesOlder varieties

Successful and well adopted Successful and well adopted

Fertilizer relatively inexpensive Fertilizer relatively inexpensive

Grower Interest in FertilityGrower Interest in Fertility

Newer variety responses to fertilizerNewer variety responses to fertilizer

– Star, Duke, Reveille, O’NealStar, Duke, Reveille, O’Neal

Grower Interest in FertilityGrower Interest in Fertility

Newer variety responses to fertilizerNewer variety responses to fertilizer

– Star, Duke, Reveille, O’NealStar, Duke, Reveille, O’Neal

Possible benefit from N during Possible benefit from N during fruitingfruiting

Grower Interest in FertilityGrower Interest in Fertility

Newer variety responses to fertilizerNewer variety responses to fertilizer

– Star, Duke, Reveille, O’NealStar, Duke, Reveille, O’Neal

Possible benefit from N during fruitingPossible benefit from N during fruiting

Better use of liquid vs. dry fertilizerBetter use of liquid vs. dry fertilizer

– 5-10-5 liquid5-10-5 liquid

– 6-12-6 liquid6-12-6 liquid

Challenges in Fertility WorkChallenges in Fertility Work

Blueberry is a perennial plantBlueberry is a perennial plant– Plant takes up N in one seasonPlant takes up N in one season– Response may take several seasonsResponse may take several seasons

Application of fertilizer during fruiting Application of fertilizer during fruiting may dislodge berries from plantmay dislodge berries from plant– Slow release N to avoid thisSlow release N to avoid this

Challenges in Fertility WorkChallenges in Fertility Work

Blueberries are grown on mineral and Blueberries are grown on mineral and organic soilsorganic soils– Range of N from organic matterRange of N from organic matter

LeonLeon

Lynn Lynn Haven Haven

MurvilleMurville

PamlicoPamlico

Challenges in Fertility WorkChallenges in Fertility Work

Low soil pH may Low soil pH may affect soil N affect soil N reactionsreactions

– Conversion to Conversion to nitratenitrate

– Where does N go???Where does N go???

Blueberry N Use & SourceBlueberry N Use & Source

Fairly inefficient in using NFairly inefficient in using N

Ammonium (NHAmmonium (NH44++) preferred over ) preferred over

nitrate (NOnitrate (NO33--))

Mostly ammonium N in 14-28-14 Mostly ammonium N in 14-28-14

Studies showing higher yields with Studies showing higher yields with sulfur-coated ureasulfur-coated urea

Research Objective in 2009

Evaluate plant nutrition and overall plant growth

– Standard dry and liquid grower fertilizers

– Slow-release N products

Mixed with P and K Mixed with P and K sources to give similar sources to give similar rates of all nutrientsrates of all nutrients

Research 2009Research 2009

Castle Hayne StationCastle Hayne Station

7 fertility treatments per row 7 fertility treatments per row – (6 plants / treatment)(6 plants / treatment)

Duke, O-Neal, Star varietiesDuke, O-Neal, Star varieties– 2 rows of each variety for total of 6 rows2 rows of each variety for total of 6 rows– Variety / row = replicationsVariety / row = replications

Research in 2009 Research in 2009 (7 (7 treatments)treatments)

1.1. Control Control (no fertilizer)(no fertilizer)

2.2. Standard fertility Standard fertility (dry 14-28-14 & 18-46-0)(dry 14-28-14 & 18-46-0)

3.3. 5-10-5 liquid 5-10-5 liquid (increase efficiency by placement)(increase efficiency by placement)

Slow-release N treatmentsSlow-release N treatments (potential increase in N availability during fruiting)(potential increase in N availability during fruiting)

4.4. UreaUrea

5.5. Sulfur-coated ureaSulfur-coated urea6.6. Nitamin 30L Nitamin 30L (urea polymer, triazone, liquid N)(urea polymer, triazone, liquid N)

7.7. Florikan (Florikan (13-13-17, 92% 13-13-17, 92% polymer-coated NH4+ & NO3

-)

FertilizersFertilizersUrea

Sulfur-coated Urea

Florikan

14-28-14

Research 2009Research 2009

Soil sampled for nitrate and fertilitySoil sampled for nitrate and fertility– 4 times (Mar 26, May 4, Jun 26, Aug 5)4 times (Mar 26, May 4, Jun 26, Aug 5)

Plant tissue sampled Plant tissue sampled – Jun 26Jun 26

GrowthGrowth– Oct 29 Oct 29 — measurements (H × W)— measurements (H × W)– Dec 22 Dec 22 — pictures— pictures

Results

Soil Fertility in Top 12 InchesSoil Fertility in Top 12 Inches

HMHM W/VW/V CECCEC pHpH BSBS KK PP%% g/ccg/cc meq/100 meq/100

cccc%% --mg dm--mg dm-3--

0.680.68 1.261.26 2.92.9 5.05.0 4747 3131 119119

0.680.68 1.281.28 2.72.7 5.25.2 5555 2323 8080

Appears to be no differences in treatments for a given depth

Note P differences between depths

Treatment   N P K Ca Mg

---------------------------%---------------------------

Grower Std (14-28-14) 1.51 a 0.13 ab 0.48 a 0.68 b 0.18 b

5-10-5 Liquid 1.53 a 0.13 ab 0.49 a 0.66 b 0.18 b

Urea-N 1.58 a 0.13 ab 0.47 a 0.63 b 0.17 b

Sulfur-coated Urea 1.6 a 0.13 ab 0.45 a 0.62 b 0.17 b

Nitamin 1.58 a 0.14 ab 0.47 a 0.62 b 0.17 b

Florikan (13-13-17) 1.64 a 0.15 a 0.47 a 0.67 b 0.19 b

Check 1.46 a 0.12 b 0.40 b 0.86 a 0.23 a

Plant Nutrient LevelsPlant Nutrient Levels

Sufficiency Plant Nutrient Sufficiency Plant Nutrient LevelsLevels

Source N P K Ca Mg

-------------------------------------%--------------------------------------------

SERA 6- Rab 1.20 – 1.70 0.08 – 0.20 0.35 – 0.60 0.25 – 0.70 0.14 – 0.20

UGA- High 1.8 - 2.1 0.12 - 0.4 0.35 - 0.65 0.40 - 0.80 0.12 - 0.25

UGA- Rab 1.2 - 1.7 0.08 - 0.20 0.35 - .60 0.25 - 0.70 0.14 - 0.20

Pl. An. Hdbk II

High- Prod.

1.45 - 2.20 0.10 - 0.40 0.40 - 0.90 0.35 - 0.80 0.12 - 0.40

Pl. An. Hdbk II

High- Res.

1.44 - 1.65 0.09 - 0.11 0.44 - 0.72 0.62 - 0.73 0.15 - 0.27

2009

Study Average

1.57 0.14 0.47 0.65 0.18

Growth as Affected by Growth as Affected by TreatmentTreatment

0

20

40

60

80

100

120

140

160

180

200

GrowerStd.

GrowerStd.-Liquid

Urea- Gr.Std.

SCUrea-Gr. Std.

Nitamin-Gr. Std.

Florikan Contol

Treatment

Pla

nt

Vo

lum

e (L

iter

s)

bcabc abc a ab

abc c

Replications of Star Replications of Star

Gr. StdDry

Gr. StdLiquid

Urea S-CoatedUrea

Nitamin Florikan Check

Gr. StdDry

Gr. StdLiquid

Urea S-CoatedUrea

Nitamin Florikan Check

Replications of O’Neal Replications of O’Neal

Gr. StdDry

Gr. StdLiquid

Urea S-CoatedUrea

Nitamin Florikan Check

Gr. StdDry

Gr. StdLiquid

Urea S-CoatedUrea

Nitamin Florikan Check

Replications of DukeReplications of Duke

Gr. StdDry

Gr. StdLiquid

Urea S-CoatedUrea

Nitamin Florikan Check

Gr. StdDry

Gr. StdLiquid

Urea S-CoatedUrea

Nitamin Florikan Check

Thoughts on the Study One-year of data

– No conclusions can be drawn

Considerable variability in plant growth – Treatments look promising– Differences may become more pronounced

over the next few years

Soil nitrate data puzzling– Soil heavily amended with pine bark

Further StudiesFurther Studies

Expand this study to grower fields on Expand this study to grower fields on different soil typesdifferent soil types

Implement incubation studies in Implement incubation studies in glass flasks with sampling intervals glass flasks with sampling intervals to determine N reactions at low pHto determine N reactions at low pH

Study rock phosphateStudy rock phosphate

– Potential slow release of P on organic Potential slow release of P on organic soilssoils