Question

The importance of soil for plant growth is:
A. Soil provides water
B. Soil provides nutrients
C. Soil provides support
D. Both A and B

Answer 1

Hint: Plant requires several mineral soluble minerals for its growth. Plants are autotrophs, i.e., they can produce their own food using the available abiotic resources. Biotic factors also influence plant growth.

Complete answer: Plants exhibit a positive geotropic effect. It means that the roots of the plant grow towards the center of gravity, I.e., downwards.
This positive geotropic effect is the driving force for the roots to grow into the soil. The roots spread across the soil layers for the absorption of water and nutrients.
1. The nutrients required for plant growth that are absorbed from the soil are magnesium, manganese, selenium, calcium, phosphorus, potassium, nitrogen, etc. Of these, nitrogen, potassium, and phosphorus are major requirements (NPK fertilizer).
2. Water is absorbed from the soil for photosynthesis in the leaves to produce carbohydrates and oxygen. Water is absorbed into the roots because of the difference in solute (Minerals) concentration across the root. Roots have relatively higher solute concentration, hence water moves into the roots.
3. Nitrogen is absorbed in the form of nitrates. Nitrates help the strong foliage growth by affecting leaf development. It is also responsible for giving plants it’s green coloring by helping with chlorophyll production and distribution.
4. Phosphorus is responsible for assisting the growth of roots and flowers. It also helps the plants to withstand environmental stress and harsh winters.
Potassium strengthens plants. It contributes to the early growth and it also helps in retaining water. It also affects the plant’s disease and insect/ pest suppression ability.

So the correct answer is Option 4: Both A and B

Note: Magnesium contributes to the green coloration of plants
Sulfur helps the plants to resist diseases as well as contributes to plant growth and seed formation. They also aid in the production of amino acids, proteins, enzymes, and vitamins.