NATIONAL ONION LABS' AUSTRALIA

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NUTRIENT MAPPING AND MANAGEMENT FOR OPTIMISING
YIELD IN ONIONS IN SHORT COPS TM FOR ONIONS
TREVOR TWIGDEN Consulting Horticulturist
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BACKGROUND

• VARIETY AND LOCATION DO NOT ENSURE SWEETNESS
  IN MILD ONIONS
• FIELD VARIABILITY IN SWEET ONIONS IN USA LED
  TO RESEARCH
• TO INDENTIFY CAUSES
• PREPLANT AND PREHARVEST SOIL TESTING LINKED TO
  PUNGENCY
• TESTING BY GPS
• RESEARCH TEAM FROM UNIVERISTY OF GEORGIA LED
  BY Dr BILL RANDLE
• COMMERCIALISED BY DAVID BURRELL, FOUNDER,
  NATIONAL ONION LABS
• FUNDAMENTALLY PUNGENCY IS A STRESS RESPONSE

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COMMERCIALISTION OF THE INVESTIGATIVE MODEL TO
IDENTIFY CAUSES OF STRESS RESULTED IN
DEVELOPMENT OF COPS TM
CROP OPTIMISATION PROGRAMS FOR ONIONS
NOW BEING USED IN FRESH AND STORAGE CROPS IN
AUSTRALIA
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• USE GPS TO INDENTIFY RECORD SAMPLING SITES
• SOIL SAMPLING, PREHARVEST PRE HARVEST
• - pH, OM ,CEC, P, K ,Ca ,Mg, Na, S, B, Nz,
  Mn, Fe, Cu, and Cl
• PRE HARVEST BULB HARVESTING
• - YIELD, BULB NUMBER, BULB SIZE, BULB
  HEALTH, PUNGENCY, SUGARS
• RESULTS MAPPED
• - PREPLANT TO INDENTIFY REMEDIAL TREATMENT
• RESULTS ANALYSED STATISTICALLY
• - AT HARVEST TO IDENTIFY CAUSAL
  RELATIONSHIPS
• RESULTS ARE CUMULATIVE BECAUSE THEY ARE
  OBJECTIVELY MEASURED

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TYPICAL COLLECTION PATTERN
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TYPICAL YIELD VARIATION

• AVERAGE FOR LOWEST 40 85.9 t/ha
• AVERAGE FOR TOP 40 97.2 t/ha

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TYPCIAL PUNGENCY VARIATION IN LATE BROWNS

• LOWEST 6.7 HIGHEST 11.1 MEAN 8.8
• MEASURED BY MODIFIED SCHWIMMER WESTON TECHNIQUE
  
• AT WAGGA WAGGA

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NUTRIENT LEVEL VARIATION

• PHOSPHORUS LOWEST 130 HIGHEST 315
  AVERAGE 200ppm
• POTASSIUM LOWEST 80 HIGHEST 280
  AVERAGE 150ppm

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NUTRIENT RATIOS

• Ca/Mg LOWEST 4.9 HIGHEST 12.3 AVERAGE 7.6
• K/Mg LOWEST 0.65 HIGHEST 1.34 AVERAGE 0.89

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IRON

• LOWEST 40 HIGHEST 240 AVERAGE 90ppm

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NON NUTRIENT STRESS EFFECTS

• POOR WATER DISTRIBUTION

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