Question

Most friable soil is:
a. Sand
b. Clay
c. Loam
d. Parent material

Answer 1

Hint: Friable soil is the type of soil, which can be easily broken down into small fragments. This type of soil is very good for the plant growth. The root growth is enhanced in such types of soil. The texture of sand is very crumbly which is why it can be easily broken down into small fragments.

Complete answer:
To solve the question we must learn about the types of soil and their texture. Soil is the topmost layer of the lithosphere. It is broadly classified into three types:

>Sandy soil: This type of soil sand consists of finely divided rocks and lacks nutrients and minerals to support plant growth. However, through mulching and addition of organic blends it can be made suitable for plant growth. Due to their texture, they do not retain water, which is vital for the roots. Vegetables such as zucchini, potato and some shrubs like tulips and hibiscus grow well in this oil.

>Clayey soil: These particles are tightly packed together and are rich in nutrients. When wet they are sticky and thick while dry they are smooth and finer. Since they are closely packed, when wet they do not allow water to penetrate through the soil. But if water is abundant they become water-logged. Fruit trees and ornamental plants grow well in this soil.

>Loamy soil: Loamy soil is considered the best for growing crops and plants because it contains equal amounts of both sand and clay. It is rich in humus and has good water retention capacity. This soil is suitable for most of the berries, bamboos, climbers and tubers.

Hence, the correct answer is option (a).

Note: Soil used for farming should consist of all the nutrients necessary for the plant growth along with good water retention capacity. Clayey soil can be made more friable by using earthworms. Earthworms break down the organic matter in the soil into nutrients that are used by the plants. Since they move in the soil, they form tunnels, which aerates the soil.