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Potassium is the single largest quality driver on pineapple. K controls fruit size, sugar accumulation (Brix), shelf life, and acid balance. Deficiency shows as yellow-orange older leaves with tip die-back and, at harvest, as small, low-Brix, poor-shelf-life fruit even if canopy looks acceptable. Regional priority: High on mineral upland, BRIS, and any block older than one cycle without full K replacement.

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When pineapple is most vulnerable

From late vegetative (month 10) through fruit development (month 18). K demand peaks between forcing and fruit filling.

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How potassium deficiency shows in satellite data

  • Block-wide NDVI below phase baseline, especially on light soils.
  • Slow, multi-month decline; not sudden.
  • Less directly visible than N deficiency because K affects fruit quality more than canopy greenness.
  • Best confirmed by D-leaf analysis and fruit sampling.

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Field symptoms

  • Yellow-orange chlorosis on older leaves, starting at the tips and margins
  • Necrotic (dead) leaf tips in advanced deficiency
  • Reduced fruit weight and small “eyes” (fruitlets)
  • Low Brix (< 12) and poor flavor
  • Short shelf life and translucent flesh at ripening
  • Increased lodging of fruiting plants (weak peduncles)
  • Increased susceptibility to sunburn, mealybug wilt, and heart rot

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Reduce the damage by

  • Muriate of potash (MOP, KCl) as the standard K source for processing blocks - typically 500 to 900 kg/ha per cycle, split into 4 to 6 applications.
  • Sulphate of potash (SOP) for fresh-market MD2 blocks - MOP chloride can depress Brix at high rates.
  • Foliar K (KNO3, K2SO4) through the leaf axil in the 6 weeks before forcing.
  • Split applications - single large doses leach on sandy soils.
  • Balance K with N and Mg - typical K:Mg target 3:1 on mineral soils.
  • D-leaf analysis at 8 to 10 months - target 3.0 to 3.5% K in the D-leaf. This is a generic target with no site, soil, cultivar or season qualifier, so it supports inside or outside and no finer grade — see Reading a tissue analysis.
  • Return crop residues to the block at destruction to recycle K.

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Set an alert for early warning

Turn the diagnosis into a trigger. K deficiency is a slow trend and quality signal, so combine an NDVI trend alert with a scheduled D-leaf and Brix check.
Recommended settings for potassium on pineapple:
  • NDVI trend alert - trigger when the block’s 6-week moving NDVI drops more than 5% below the phase baseline.
  • D-leaf sampling reminder - month 8 to 10 (before forcing) and month 15 (mid fruit development).
  • Brix check - schedule a fruit-sampling round at ripening; flag blocks with Brix below 12.