Potato Review Group

Contents

Background

Zinc in soil

Foliar application of zinc

Further information:

Zinc notes

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Background

  1. Zinc, like phosphorus, has little mobility soil and uptake therefore depends upon root growth. More …
  2. Zinc is important for formation of proteins. Inadequate zinc nutrition may result in increased production of phenols and thus an increased susceptibility to pigment formation after bruising. More …
  3. Zinc deficiency at emergence may restrict the rate of growth of individual tubers, resulting in a low rate of tuber bulking. More …
  4. Foliar application of zinc while stolon tips are swelling can reduce the number of progeny tubers formed. More …

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Zinc in soil

  1. Zinc in soil tends to be not very soluble and therefore only a small proportion of total is available to plant; this is improved by adequate soil moisture and targeted application to soil regions where roots are most likely to grow.
  2. Zinc is more available at lower soil pH (pH < 6.0), and least available in soils which have one or more of:
    • low total Zn (e.g. very sandy soils),
    • high OM (> 3 %),
    • high CaCO3,
    • neutral to alkaline pH,
    • moisture deficiency,
    • highly available P.

More …

 

Foliar application of zinc

  1. Rate of application: 600-800 g Zn ha-1. More …
  2. Application of zinc with phosphite can result in greater response than application of either nutrient alone but remember that phosphite provides health but not nutritional benefits. More …
  3. On zinc deficient sites, particularly if soil is dry, apply at emergence. More …
  4. On zinc deficient sites or if P : Zn ratio in foliage is > 400 : 1 and if bruising is a concern continue to apply during tuber bulking. More …
  5. Do not apply zinc while stolon tips are swelling. More …
  6. Sufficient” concentration = 45 – 230 ppm Zn when plants are 30 cm high. More …
  7. Care should be taken not to over-apply foliar Zn and not to apply unless the crop is Zn deficient. A study with the aim of biofortification (increasing Zn concentration in potato for the purpose of human health) showed significantly lower tuber yield when foliar application ≥ 29 kg Zn/ha and a trend for less biomass as application amount increased. More …
  8. To optimise Zn concentration in tuber from foliar Zn applications, spread the required amount as more frequent, smaller, applications. This is in addition to following the usual recommendations about optimising foliar application of nutrients, and may be due to either poor translocation of Zn within the plant or poor uptake through leaf. More …

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Further information

Zinc notes

Foliar micro-nutrition 2017 (Repeat applications may increase concentration in tubers but excessive applications can be detrimental to yield)

Foliar nutrient applications 2011 (Phosphite may enhance effects of zinc)

Nutrition experiments 2010 (Zinc experiment confirms detrimental effects if applied during stolon tip swelling; rate of application = 800 g Zn / ha)

Nutrition and quality 2010 (Includes enhancement of black scurf control with a zinc product)

Micro-nutrients 2001 (Includes zinc physiology)

Foliar micro-nutrients 2000 (Includes zinc applied with other micro-nutrients, which can reduce uptake of zinc)

Tuber fry colour 1998 (Includes influence of zinc on amino acids)

Bruising and damage 1998 (Including influence of zinc on susceptibility to bruising)

Notes for 1993 (Chapter 9: Zinc applied with surfactant or with magnesium. Chapter 10: Early season application.)

Seminar 1 Notes 1992 (Chapters 4-7: Application of zinc and experiment results – foliar application can be beneficial at emergence but detrimental during stolon tip swelling)

 

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