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