Directions: Read the Assertion (A) and Reason (R) carefully and choose the correct alternative. Assertion (A): Cotton is mainly grown in alluvial soils. Reason (R): Alluvial soils are very fertile and rich in plant nutrients.

Introduction / Context:
This Assertion and Reason question is from Indian agriculture and soil types. It tests knowledge about the preferred soil for cotton cultivation and the general fertility of alluvial soils. You must decide whether cotton is primarily associated with alluvial soils and whether the fertility of alluvial soil is correctly described in the Reason. It is important to recall the difference between alluvial and black soils and which crops they support best.

Given Data / Assumptions:

• Assertion (A): Cotton is grown in alluvial soils.
• Reason (R): Alluvial soils are very fertile.
• Alluvial soils are formed by deposition of silt and sediments by rivers.
• Black soils, also called regur soils, are found in the Deccan plateau and are often linked with cotton.

Concept / Approach:
Cotton requires a warm climate with moderate rainfall and a soil that can retain moisture but also has good drainage. In India, cotton is classically associated with black soils that have high clay content, good moisture retention, and are found in Maharashtra, Gujarat, and parts of Madhya Pradesh. Alluvial soils are indeed fertile and support many crops such as wheat, rice, sugarcane, and pulses, but they are not the typical textbook soil type specifically linked with cotton. Therefore we must judge Assertion and Reason separately and then examine their relationship.

Step-by-Step Solution:
Step 1: The Assertion claims that cotton is grown in alluvial soils. While cotton can be grown in various soils with proper irrigation and management, the classic and most suitable soil for cotton in exam oriented geography is black soil. Step 2: Black soils have properties such as high moisture retention and rich lime content that favour cotton cultivation. Hence the standard statement in many textbooks is that cotton grows best in black soils. Step 3: Therefore, as per typical school level generalisation, Assertion (A) is considered false because it suggests alluvial soils as the main or typical soil for cotton. Step 4: Now examine Reason (R). Alluvial soils, found mainly in river plains, are indeed very fertile. They contain fine particles, mineral nutrients, and often support multiple crops per year. Step 5: Since many different crops thrive on alluvial soils, the statement that alluvial soils are very fertile is true. Step 6: Thus we have Assertion (A) false and Reason (R) true, and clearly Reason (R) cannot act as a correct explanation of a false Assertion.

Verification / Alternative check:
Standard geography texts state that cotton is a crop of black soils of the Deccan plateau. Alluvial soils are usually associated with crops such as wheat, rice, sugarcane, and jute in the Indo Gangetic plains. This consistent pairing in exam material confirms that the Assertion in the question is not aligned with the usual teaching, whereas the description of alluvial soils as fertile is well supported.

Why Other Options Are Wrong:
Options that treat Assertion (A) as true ignore the strongly emphasised Black cotton soil association. Options that say Reason (R) is false contradict basic facts about alluvial soil fertility. The option that claims both are false is also wrong because the fertility of alluvial soils is a well known fact.

Common Pitfalls:
Some candidates may assume that because cotton can be grown in places with alluvial soils under certain conditions, the Assertion must be correct. Exam questions at this level, however, expect the recognition of the main or ideal soil type associated with the crop, not all possible conditions. Remember the standard pairing of cotton with black soil for such questions.

Final Answer:
Assertion (A) is false, but Reason (R) is true, so the correct option is Assertion (A) is false, but Reason (R) is true.