Question

The Law which states that whatever is being taken by plants from soil needs to be restored to maintain the nutrient supplying capacity of the soil is called "Law of Restitution" and it is propounded by:

• A. Justus von Liebig (1840)
• B. Hilgard (1888)
• C. J.B. Boussingault (1802-1882)
• D. E.W. Hilgard (1833-1916)

Hint:

Do not confuse this with Liebig's Law of the Minimum, which is about limiting nutrients, not restoring removed ones.

Answer 1

The Correct Option is C

This question is really about matching a named law in soil fertility to the correct scientist, and the trap is that two other big names in soil science are sitting right there as distractors.

1. Justus von Liebig (1840): Liebig's lasting contribution is the Law of the Minimum, the idea that plant growth is held back by whichever nutrient is scarcest, relative to what the plant needs. That is a different law from restitution.
2. Hilgard (1888): This points to the same scientist as option 4, associated with soil genesis and alkali soil studies in America, not with the restitution concept.
3. J.B. Boussingault (1802-1882): Boussingault, working in France in the same broad period as Liebig, is the scientist credited with stating that a crop's removal of nutrients from the soil must be restored to it, otherwise fertility keeps declining, which is exactly the Law of Restitution described in the question.
4. E.W. Hilgard (1833-1916): Again this is the American soil scientist known for pioneering soil survey and pedology work, not restitution.

Since the question is describing the return-of-nutrients idea word for word, the answer has to be Boussingault.

Let's summarize:

• Liebig gave the Law of the Minimum.
• Both Hilgard options refer to the same soil scientist, known for soil genesis work.
• Boussingault is the one who framed the Law of Restitution.

So option 3, J.B. Boussingault, is correct.