Soil Conditions

Zinc is of vital importance for growth and seed production in grain crops. In addition, zinc uptake and it’s translocation to the shoots is inhibited by high concentrations of bicarbonate , which occur as a result of residue decomposition and the production of carbon dioxide in the soil.

In high rainfall areas, zinc and calcium deficiencies should be considered as the most common cause of poor growth in cultivated crops.

Certain herbicides may also induce a zinc deficiency in crops. Zinc- deficient plants are therefor more sensitive to herbicide damage than zinc-efficient plants.

Healthy roots equals healthy plants and healthy yields (in more than one sense..!!!). Our Zinc-Flo efficiently addresses all these issues to ensure a phenomenally positive result .

Zinc-Flo can also be used to manage fungus and diseases in planted pastures for cattle and sheep.


Zinc-containing fertilizers are not very effective against zinc deficiency in plants. Application of zinc oxide to the soil will supplement the zinc content of soils. Indigenous zinc in the soil is then taken up by plants during release of hydrogen from ammonium nitrogen.

Zinc sulphate is effective when large amounts are broadcast, however, when blended into fertilizers it reacts with phosphate to form compounds which are not water soluble. Zinc-Flo is chemically researched and adapted (thus liquid form already) to easily and effectively overcome these problems.

Effectiveness of zinc-containing fertilizers depends on the nitrogen source, the phosphorous source and also the zinc source that is being used in fertilizing plants. Zinc sulphate is water soluble, but when applied to the soil it reacts with hydroxides and phosphorous to form compounds which are not water soluble any more. When an acid was limed, water-soluble zinc was found to decrease from 97% to 29% with the use of MAP and from 54% to 0% with the use of DAP. Most fertilizers contain urea or nitrate as their source of nitrogen. In the soil, urea is converted into nitrate nitrogen, which is known for its negative effect on zinc uptake by plants. Acid conditions are required for zinc oxide to become soluble in water. When plants are fertilized with ammonium nitrogen, acids are produced in the rhizoshere and this will enable plants to absorb indigenous zinc in the soil, as well as applied zinc such as zinc oxide.


Stunted growth, yellowing and drastic decrease in leaf size are symptoms of severe zinc deficiency in maize. Such symptoms are most pronounced on acid soils fertilised with blends of urea and the alkaline form of ammonium phosphate (also known as DAP). Zinc deficient plants never grow as tall as zinc – efficient plants and, they are less tolerant to heat stress. Zinc-deficient plants are also more susceptible to stem and cob rot. In the final analysis, yields are depressed and grain of low hectolitre mass is produced. The South African product, Zinc-Flo for all grain crops, is highly efficient against a zinc deficiency in seedlings. Best results are obtained when the product is used at the time when crops are planted.

Wheat and Barley

In zinc-deficient cereals, grain quality is depressed due to impairment of photo-synthesis and, a failure of zinc-dependant enzymes to protect chloroplasts from the harmful effects of sunlight (especially during times of intensive sunshine after good rainfall). Soon after the leaves have died, ears will also turn white in zinc-deficient plants. Grain yields could still be average but, quality of the grain is negatively affected.


Legumes such as soya and dry beans are often more seriously affected by a zinc deficiency than crops from the grass family. Symptoms usually occur in produce which have been fertilised with too much nitrogen. Plant growth is even more restricted with high applications of urea or nitrate nitrogen. Moreover, necrotic lesions usually occur on middle-aged leaves of zinc-deficient plants and should be attributed to poor calcium uptake by zinc-deficient plants on acid soils.

Soil and Foliar Application

A liquid applicator, mounted on the planter can be used to apply Zinc-Flo to the soil next to the seeds of maize, sorghum, sunflower, soya and dry beans. Using this method, sufficient quantities of water-soluble zinc is made available to the roots of germinating seeds.

For wheat and barley a full cover spray is recommended before or just after emergence. Apart from activity against zinc deficiency, Zinc-Flo also has the capacity to control mildew and yellow rust in wheat and barley. A tank mix of systemic fungicides and Zinc-Flo is required for effective control of both fungal and physiological diseases in wheat and barley.

A combination of Zinc-Flo and Demildex should be used as a regular foliar spray on dry beans to prevent micronutrient deficiencies as well as fungal diseases such as mildew and anthracnose.