Crop production can be maximised by improving plant nutrition and soil fertility. Often soil conditions do not support optimum growth due to lack of or low doses of specific nutrients. Micronutrients The term “micro” or “trace” refers to the quantity required by plants and NOT to the regulative importance of nutrients.

Elements needed in plant nutrition

Boron
Required in protein synthesis, important in cell division and development of normal root systems. Deficiencies effect flowering, fruiting and seed formation. Regulates nitrogen and carbohydrate.

Copper
Required as a catalyst in respiration and a constituent in enzymes. Copper has an indirect role in chlorophyll formation and is essential for plants’ reproductive stages.

Iron
Iron is essential for chlorophyll synthesis and respiration.

Manganese
Required for some enzymes involved in the breakdown of carbohydrates and nitrogen metabolism. Manganese is necessary for the formation of riboflavin, ascorbic acid and carotene.

Molybdenum
Needed for symbiotic nitrogen fixation in legumes and protein synthesis in all plants.

Zinc
Required for growth hormone and seed production and is involved in protein synthesis and maturation of seed.

Micronutrient deficiencies in crops can be just as devastating as a deficiency of nitrogen, phosphorus or potassium. The relative quantities are illustrated by the following table, showing typical concentrations of the various elements in leaf tissue and soil.

Micronutrient Proportions (typical concentration (ppm))