Correct Option
The correct option isTo retain water so it stands in the field for rice cultivation.
Explanation
Terrace farming is an agricultural technique adapted for hilly and mountainous regions, where slopes are cut into a series of flat platforms or "steps" to create arable land and prevent soil erosion.Detailed Analysis:
- Requirement of Rice Cultivation: The primary crop grown in these regions, particularly in Nagaland (e.g., by the Chakhesang community in Chizami), is paddy (rice). Wet rice cultivation requires the soil to be submerged in standing water for optimal growth.
- Function of Raised Sides: On a natural slope, water drains away rapidly. To counter this, farmers construct raised embankments or bunds along the edges of each flat plot. These raised sides trap rainwater and irrigation water, ensuring it remains stagnant in the field.
- Elimination of Other Options:
- To prevent animals from entering the fields.: While barriers may deter some animals, the specific design of "raised earth" is for water management, not fencing.
- To mark the boundary between different families' land.: While bunds do demarcate land, their physical elevation is specifically engineered for hydrology rather than just administrative division.
- To allow easy movement of farmers between steps.: Movement is facilitated by the steps themselves, but the raised edges are an obstruction to movement rather than an aid; their purpose is agricultural.
Key Takeaway: The raised borders in terrace farming serve a hydrological function, enabling the retention of standing water necessary for paddy cultivation on steep slopes.