Step 1: Understanding the Concept:
To sustain soil fertility over long periods of cultivation, nutrients removed by harvested crop components must be replenished. This balance is defined by the Law of Restitution.
Step 2: Detailed Explanation:
1. The Law of Restitution was formulated by the German chemist Justus von Liebig.
2. It states that the nutrient supplying capacity and overall fertility of a soil can only be preserved if nutrients removed by crops (and losses via leaching or erosion) are restored to the soil in equivalent quantities through fertilizers, manures, or crop residues.
3. If restitution is neglected, soil reserves deplete, leading to a decline in crop productivity over time.
Step 3: Final Answer:
The principle described is Liebig's Law of Restitution.