Step 1: Understanding the Concept:
Cropping systems describe the spatial and temporal arrangement of crops on a given land area.
Step 2: Detailed Explanation:
Matching each cropping system in List I with its definition in List II:
1. Double cropping (A) $\to$ Growing 2 crops per year in a sequence on the same land (IV).
2. Inter cropping (B) $\to$ Growing 2 or more crops simultaneously on the same field in definite row proportions (I).
3. Mixed cropping (C) $\to$ Growing 2 or more crops simultaneously with no distinct row arrangement (III).
4. Ratoon cropping (D) $\to$ Cultivation of crop regrowth from root or stem bases after harvest, such as in sugarcane (II).
Step 3: Final Answer:
Matching summary: A $\to$ IV, B $\to$ I, C $\to$ III, D $\to$ II.