'Milpa'. 'Roca', 'Ladang' are different names of which of the following?

The terms 'Milpa', 'Roca', and 'Ladang' are regional names for a specific agricultural practice.

This practice involves cultivating a piece of land for a few years and then leaving it fallow to allow soil fertility to recover. After fallow, the land is used again after a long period, and cultivation moves to a new area.

Key features of this practice include:

• Rotation of land use: Farmers do not continuously farm the same plot.

• Fallow period: Land is left uncultivated to restore nutrients.

• Often involves slash-and-burn clearing to prepare the land.

In India, this practice is commonly known as Jhum cultivation.

Why the other options are incorrect:

• Open-cast mining: This is a method of extracting minerals from the earth's surface and is unrelated to agriculture.

• Earthquake waves: These are seismic vibrations that travel through the Earth and are not related to farming systems.

• Rainwater harvesting: This is a water conservation technique and not a method of land cultivation.

Thus, the correct answer is shifting cultivation.