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Zinc and silicon join forces against heat stress

by | Jul 9, 2020 | Agriculture | 0 comments

What does zinc do?

Zinc is an essential plant nutrient and involved in may physiological processes.

  1. During heat stress the membranes of cells are damaged and “poisonous radicals” are formed. Zinc is involved in the detoxification of these radicals like super-oxide (O2- ). Damaged membranes leak amongst other K, sugars and amino acids which in turn destroy chlorophyll cause die-back and stunted growth especially in spring and early summer growth.
  2. Zinc plays a role in keeping the integrity of the membranes. Damaged membranes inhibit the absorption of water and nutrient elements and leave the tissue more susceptible to infections.
  3. Zinc applications after the damage occurred are not effective. The zinc-status must be high before the onset of the stress conditions.

What does silicon do?

Silicon is not an insecticide, a fungicide or an essential plant nutrient. It’s main role in plant production is to support the plant’s natural mechanisms to withstand invasion by insects and microbes and adverse climatic conditions.

 

  1. The first action is to increase the physical strength of tissue like twigs, stems and leaves and keep them longer in operation during stress conditions. Thereby increases the photosynthetic capacity and hence production.

 

  1. The conducting vessels in stems keep on transporting water upwards for longer when water stress is experienced. Thus transpiration and cooling of the leaves will be sustained for longer periods.

 

  1. Increased water flow, prolonged cooling and protect the leaf membranes against heat damage.

 

Precaution

To reap the advantages of extra zinc and silicon during adverse conditions, the Zn and Si must be applied before the onslaught of the stress. Two foliar sprays at 100% petal drop and again two weeks later should be applied as follows to ensure that the zinc stays in solution.

  1. Fill the spray tank with water.
  2. Add 200ml Nontox SilicaR (Available at PBR. Contact DS Pretorius at 082-469 1473) per 100litre water and stir.
  3. Add a buffer to reduce the pH to less than 6,00. Stir.
  4. Now add 200ml zinc nitrate (5,5% Zn) per 100 litre water. Stir and apply to the leaves in large drops. Apply between 4000 and 6000 litres per ha to mature trees.

     JGK CONSULTING