Question

A farmer adds/ supplies Na, Ca, Mg and Fe regularly to his field and yet he observes that the plants show deficiency of Ca, Mg and Fe. Give a valid reason and suggest a way to help the farmer improve the growth of plants.

Answer 1

Reason behind deficiency in this case:

In this case, the plants are having deficiency of Ca, Mg and Fe in spite of proper supply due to manganese toxicity. Mn is a micronutrient and plays an important role during photolysis reaction in the process of photosynthesis. However, its toxicity leads to the following:

● It competes with iron and magnesium for uptake which results in reduction in their uptake.

● It competes with Mg for binding to the enzymes, thus affecting enzyme interaction.

● It inhibits the translocation of calcium in the shoot apex. As a result the plant shows deficiency symptoms of Ca, Mg, Fe.


Remedy:

The farmer must therefore make sure that the amount of manganese is not in excess in the soil. The growth of the plants can be improved by the following methods:-

● As low soil pH results in such conditions, manganese toxicity can be reversed by application of lime or dolomite. This will help raise the soil pH above about 5.3.

● Ensuring that the fertilisers further being used have balanced nutrient concentrations.

● Ensuring that excessive amounts of organic matter (manure, straw etc.) are not applied in the soil as these will increase the acidity of soil.

● Avoiding problems associated with waterlogging can be done by improving drainage systems or raising the height of mounds or ridges.