Step 1: Understanding the Concept:
Diara land (riverbed) cultivation is a specialized system of growing cucurbitaceous vegetables (such as melons and gourds) on the sandy banks of seasonal rivers after floodwaters recede.
This system requires specific microclimate management techniques to ensure crop survival and growth during the dry winter and summer months.
Step 2: Detailed Explanation:
Let us evaluate both statements:
- Assertion (A): In Diara lands, the topsoil consists of dry, nutrient-poor sand with very low water-holding capacity.
To access moisture stored in the deeper subsoil layers, farmers use the ditch (or trench) system of planting.
They dig deep trenches or ditches through the sand down to the water table layer to plant the seeds, making this a standard planting system in riverbeds.
Therefore, Assertion (A) is correct.
- Reason (R): The direction in which these trenches are dug is critical for managing the microclimate.
By digging trenches in a North-West to South-East direction, the growing plants are protected from cold, dry winds (which typically blow from the North-West during winter).
This orientation also maximizes solar radiation absorption during the day.
This raises soil temperatures within the trench, promotes rapid seed germination, and conserves valuable soil moisture near the roots.
Therefore, the physical orientation directly explains why the ditch system is successfully used to manage temperature and moisture.
Both statements are correct, and (R) is the correct explanation of (A).
Step 3: Final Answer:
Both (A) and (R) are correct, and (R) is the correct explanation of (A), corresponding to option (A).