OPTIMISING BLUEBERRY SOIL CHEMISTRY REQUIREMENTS FOR PRODUCTION AND PLANT HEALTH LESSONS LEARNT ON...
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Transcript of OPTIMISING BLUEBERRY SOIL CHEMISTRY REQUIREMENTS FOR PRODUCTION AND PLANT HEALTH LESSONS LEARNT ON...
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