OPTIMISING BLUEBERRY SOIL CHEMISTRYREQUIREMENTS FOR PRODUCTION AND

PLANT HEALTH

LESSONS LEARNT ON THE NORTH COAST NSW

IAN VIMPANY – SOIL CONSULTANT (ALSTONVILLE)GEORGE JESSETT – HORTICULTURAL MANAGER (BERRYEXCHANGE)

FARM DETAILS

CORINDI PLATEAU NORTH COAST NSW

270 HECTARESSHBRABBITEYE

PRODUCTIONJULY - FEBRUARY

CHALLENGING SOILS - PHYSICAL PROPERTIES• TEXTURE• DRAINAGE• AERATION

CHALLENGING ENVIRONMENT• HIGH RAINFALL (WATER LOGGING OF SOILS)• PEST AND DISEASE PRESSURE

= SHORT LIFE EXPECTANCY FOR PLANTS (7 YEARS FOR SHB)

CHALLENGES

SOILS

GENERAL DESCRIPTION

• SHALLOW SANDY TO SANDY LOAM TOPSOILS – 20cm• UNDERLAIN BY HEAVY CLAYS – POOR DRAINAGE• MOUNDED IN RAISED BEDS – 40cm

CHALLENGING SOILS FOR BLUEBERRY PRODUCTION

• SOIL QUALITY (OR LACK THEREOF) CAN LIMIT PRODUCTION

SOIL pH (H20)= 4.5 to 5.0

PREFERRED NITROGEN SOURCE= Ammonium (NH4)

BUT DOES THIS APPLY IN ALL SOILS / GROWING CONDITIONS?

ACCEPTED THEORY

PRINCIPLE NITROGEN SOURCE WAS UREA

CHANGE TO AMMONIUM SULPHATE / MAPRapid Soil acidification (pH<4 (H20)High levels of aluminium saturation (Al>60% CEC)Low levels of calcium

= PROBLEM

Investigation of soil revealed dark stunted roots

PAST MANAGEMENT

• LITERATURE RECOMMENDS GROWING IN ACID SOILS AND USE OF SULPHUR AT pH >5.0

• CONCERNS OF UNBALANCED SOIL CHEMISTRY Should lime be considered?

• LED TO FIRST TRIALS WITH LIME 5 Micron lime through drip system @ 100kg/ha

LIME?

FIRST LIME TRIALS - 2002

pH(H20) pH(CaCl2) K Ca Mg Al Na CEC Ca/Mg EC Al%3.5 3.3 0.18 0.5 0.2 1.4 0.1 2.3 3.1 0.27 61

pH(H20) pH(CaCl2) K Ca Mg Al Na CEC Ca/Mg EC Al%4.5 4.1 0.21 3.1 0.2 0.6 0.13 4.34 14 0.25 15

AMMONIUM SULPHATE PROGRAM - NO LIME:

AMMONIUM SULPHATE PROGRAM – 1 APPLICATION LIME:

• INTIAL APPLICATIONS OF LIME FOLLOWED BY SEVERAL MORE APPLICATIONS OVER TIME

• LIMED PLANTS LOOKED HEALTHIER • POSITIVE RESULTS AND NO REDUCTION IN PLANT GROWTH• REGULAR LIMING PROGRAM – 200Kg/HA (2-3 times per

year)• IMPROVED PLANT HEALTH AND PRODUCTIVITY• PROBLEMS WITH SOILS WHEN: Low pH Al > 0.5 meq Ca < 1.0 meq

DEVELOPING STANDARDS

pH RELATIONSHIP

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 30 1 2 3 4 5 6 7 83

3.5

4

4.5

5

5.5

6

6.5

7

RELATIONSHIP BETWEEN pH(CaCl2) AND EXCHANGEABLE Ca AND Al

Aluminium (KCl)

Logarithmic (Aluminium (KCl))

Calcium (Amm-acet.)

Logarithmic (Calcium (Amm-acet.))

pH

• pH > 4.7 (CaCl2)

• Ca > 2.0 meq/100g

• Al < 0.5 meq/100g

TARGET SOIL CHEMISTRY

LOW pH/HEAVY SOIL GOOD pH/LIGHT SOIL

PLANT COMPARISONS - BELOW

LOW pH/HEAVY SOIL GOOD pH/LIGHT SOIL

PLANT COMPARISONS – ABOVE

• USE OF FINE LIME BEFORE REPLANTING Increase starting soil pH to 5.5

• REDUCE SOIL ACIDIFICATION – Change to NH4N03

• MULCH Increased pressure on reduced soil pH

CHANGES TO MANAGEMENT

• ON FARM RESEARCH AND EXTENSIVE SOIL ANALYSIS LED MANAGEMENT TO QUESTION ADOPTED NORMS FOR SOIL pH AND BLUEBERRY CULTURE (4.5 to 4.7 pH) FOR OUR SITE CONDITIONS

• TRIALS ON SMALL SCALE AREAS USING MICROFINE LIME INDICATED POSITIVE CHANGE

• ADOPTION OF LIME HAS IMPROVED SOIL CHEMISTRY AND PLANT HEALTH (LEADING TO GAINS IN PRODUCTIVITY)

• CAVEAT: APPLICATION OF THIS INFORMATION MAY NOT APPLY TO ALL SOIL TYPES

CONCLUSIONS