Question

Which organism is most useful for soil fertility?
A. Algae
B. Fungi
. Bacteria
D. Bacteriophage

Answer 1

Hint:- Soil fertility refers to the ability of soil to facilitate efficient plant growth by providing all the essential minerals, water, and other nutrients required for the plant, to give better habitat to the plants and thereby increase their yield. Soil fertility depends on many factors like the presence of macronutrients and micronutrients required for the plants in the soil, the presence of microorganisms that are necessary to the plants for their absorption of soil nutrients and water, the pH of the soil, and other chemical composition of the soil.

Complete step-by-step solution:-
Many microorganisms are directly related to soil fertility. Bacteria and fungi are very important for soil fertility. They are mainly involved in the decomposition processes and it helps in the effective absorption of minerals by the plants. The degradation of dead organic substances like leaves, flowers, carcasses of animals, etc. into simpler inorganic substances is done by enzymes produced by bacterias and fungi.
Among the minerals required for plants, nitrogen is very essential and is required in the greatest amount. Plants cannot absorb nitrogen from the atmosphere. Nitrogen-fixing bacteria are required by the plants for absorbing nitrogen from the soil. Therefore bacteria is considered the most important microorganism for effective absorption of minerals and soil fertility. Bacterias are also important for nodule formation in roots which helps to establish a direct connection between the plants and the bacteria for the exchange of nutrients.
Fungi have symbiotic relationships with the roots of plants call the mycorrhiza which forms threadlike fungal hyphae in the roads which helps in the effective absorption of like phosphorus by the plants.
Bacteriophages are viruses that attract bacteria and kill them. They are not related to the fertility of the soil.
Algae are the lower plant groups that are seen in both Terrestrial and aquatic habitats. The dead algae act as organic compounds and their decomposition can increase soil fertility.
The correct answer is option (C), Bacteria

Note:- Both fungi and bacteria are very important for soil fertility. Accurate measurement of the importance of organisms cannot be done. But based on the increased activities done by the bacteria in the soil for the absorption of nutrients by the plants we consider bacteria as the most important organism for soil fertility. Some bacterias involved in nitrogen fixation are Rhizobium, Frankia, Alnus, etc.