WORLD HISTORY

Detailed explanation-1: -Nitrogen (N) is made available to the plant from the air and soil. But most of the needed elements that are nutrients for plants come from the soil. They are not all equally important but all play a role in plant growth. Most needed are nitrogen (N), phosphorus (P), potassium (K), and sulphur (S).

Detailed explanation-2: -Humus is made up of partially decayed and partially synthesised organic materials. It is rich in nutrients and thus makes the soil fertile promoting plant growth. It makes the soil granular thereby increasing its air and water holding capacity.

Detailed explanation-3: -Alluvial soil is the most fertile soil because it has a loamy texture (contain sand, clay and slit) and is rich in humus, contains organic nutrients. A granular material composed of finely divided rock and mineral particles are called sand. Sand with clay and slit helps to increase fertility of alluvial soil.

Detailed explanation-4: -Alluvial soil is formed by deposition of alluvium and sediments carried by rivers and sea waves over many years, which make this soil very fertile. It consists of various proportions of sand, silt and clay. It is also rich in organic nutrients.

Detailed explanation-5: -The humus makes the soil fertile and provides nutrients to growing plants.

Detailed explanation-6: -Loamy Soil It has sufficient aeration. It is well suited for cultivation. Roots of plants get enough water, air, and space to grow. Suitable Crops: Loamy soil is ideal for growing crops such as wheat, sugarcane, cotton, jute, pulses, and oilseeds.