With reference to the use of manure and fertilisers, consider the following statements: 1. Continuous cultivation of crops enriches the soil with nutrients. 2. Manure is an organic substance obtained from the decomposition of plant or animal wastes. 3. Fertilisers are rich in plant nutrients like nitrogen, phosphorus, and potassium. Which of the statements given above is/are correct?

Correct Option The correct option is (c) 2 and 3 only. Explanation Soil supplies mineral nutrients to crop plants, which are essential for their growth. To maintain soil fertility and ensure healthy yields, farmers add substances in the form of manure and fertilizers to replenish nutrients depleted by farming. Statement-wise Analysis: - Statement 1 is Incorrect: Continuous cultivation of crops on the same land makes the soil poor in certain nutrients. Plants absorb minerals from the soil for growth; if crops are grown continuously without allowing the soil to recover (fallow periods) or without replenishment, the nutrient levels deplete rather than enrich. - Statement 2 is Correct: Manure is a natural, organic substance obtained from the decomposition of plant or animal wastes (such as cow dung, urine, and crop residues). It provides a lot of humus to the soil, improving its texture and water-retaining capacity, though it is relatively less rich in specific plant nutrients compared to fertilizers. - Statement 3 is Correct: Fertilisers are chemical substances produced in factories that are rich in specific plant nutrients. The most common nutrients found in fertilizers are Nitrogen, Phosphorus, and Potassium (often referred to as NPK). Examples include Urea, Ammonium Sulphate, and Super Phosphate. Key Takeaway: Manure is an organic substance that adds humus and improves soil structure, whereas fertilizers are nutrient-specific chemicals (NPK) used for rapid plant growth but can degrade soil health if used excessively.

With reference to the use of manure and… - NCERT Class 8 Science MCQ

NCERT Class 8 Science — Chapter 1: Crop production and management

mcqmedium

With reference to the use of manure and fertilisers, consider the following statements:

Continuous cultivation of crops enriches the soil with nutrients.
Manure is an organic substance obtained from the decomposition of plant or animal wastes.
Fertilisers are rich in plant nutrients like nitrogen, phosphorus, and potassium.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 8 · Page 7

Options

A1 and 2 only
B2 only
C2 and 3 only
D1, 2 and 3

Did you get this right?

Solution

Correct Option

The correct option is (c) 2 and 3 only.

Explanation

Soil supplies mineral nutrients to crop plants, which are essential for their growth. To maintain soil fertility and ensure healthy yields, farmers add substances in the form of manure and fertilizers to replenish nutrients depleted by farming.

Statement-wise Analysis:

Statement 1 is Incorrect: Continuous cultivation of crops on the same land makes the soil poor in certain nutrients. Plants absorb minerals from the soil for growth; if crops are grown continuously without allowing the soil to recover (fallow periods) or without replenishment, the nutrient levels deplete rather than enrich.
Statement 2 is Correct: Manure is a natural, organic substance obtained from the decomposition of plant or animal wastes (such as cow dung, urine, and crop residues). It provides a lot of humus to the soil, improving its texture and water-retaining capacity, though it is relatively less rich in specific plant nutrients compared to fertilizers.
Statement 3 is Correct: Fertilisers are chemical substances produced in factories that are rich in specific plant nutrients. The most common nutrients found in fertilizers are Nitrogen, Phosphorus, and Potassium (often referred to as NPK). Examples include Urea, Ammonium Sulphate, and Super Phosphate.

Key Takeaway:
Manure is an organic substance that adds humus and improves soil structure, whereas fertilizers are nutrient-specific chemicals (NPK) used for rapid plant growth but can degrade soil health if used excessively.

Your note

More from Chapter 1: Crop production and management

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With reference to weedicides, consider the following statements: 1. They are chemicals used to control weeds. 2. They are sprayed to kill the main crop along with the weeds. 3. They are best sprayed during the vegetative growth of weeds before flowering. Which of the statements given above is/are correct?

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Consider the following statements regarding the nutrient content of Manure vs Fertiliser: 1. Manure is richer in plant nutrients like nitrogen and phosphorus compared to fertilisers. 2. Fertilisers are very rich in nitrogen, phosphorus, and potassium. 3. Manure provides humus which fertilisers do not. Which of the statements given above is/are correct?

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Which one of the following is an organic soil amendment derived from the decomposition of plant or animal waste?

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