Question

Relationship between plant growth response and addition of growth factor was given by ------

• A. Baule
• B. Mitscherlich
• C. Bray
• D. Liebig

Hint:

Liebig proposed a rigid linear minimum concept, while Mitscherlich introduced the realistic curvilinear logarithmic law of diminishing returns.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Crop yield is a function of various growth factors, particularly plant nutrient levels in the soil.
Historically, scientists have attempted to model how crop yield increases with incremental additions of a limiting nutrient.
This study led to the development of yield response curves and laws of diminishing returns in soil fertility.

Step 2: Detailed Explanation:
Justus von Liebig first proposed the "Law of the Minimum," which suggested that crop yield is limited by the single nutrient in shortest supply.
However, this law assumed a strictly linear relationship up to a maximum plateau.
In 1909, E. A. Mitscherlich mathematically refined this concept.
He proposed the "Law of Diminishing Yield Increment," which states that the increase in crop yield per unit of a limiting nutrient added is proportional to the difference between the maximum possible yield and the actual yield:
\[ \frac{dY}{dx} = (A - Y) \cdot c \]
where:
- \( Y \) is the actual yield obtained.
- \( x \) is the amount of the growth factor added.
- \( A \) is the maximum potential yield.
- \( c \) is a constant representing the efficiency of the nutrient.
This logarithmic equation represents the classic curved yield response curve.
Therefore, the quantitative relationship between plant growth response and the addition of a growth factor was established by Mitscherlich.

Step 3: Final Answer:
The mathematical relationship was formulated by Mitscherlich.