Subsistence farming refers to a type of agricultural practice in which farmers grow crops or raise livestock primarily to meet the needs of their own families or local communities. It is characterized by small-scale production, low input usage, and a focus on self-sufficiency rather than commercial gain. Shifting cultivation is an example of subsistence farming.

Shifting cultivation, also known as slash-and-burn agriculture or swidden farming, is a traditional method of farming practiced in many parts of the world, particularly in tropical regions. Here is an explanation of why shifting cultivation is considered an example of subsistence farming:

1. Method of farming:
- Shifting cultivation involves clearing a patch of land by cutting down and burning vegetation.
- The ash from the burned vegetation provides nutrients to the soil, making it fertile for cultivation.
- Farmers then plant crops in the cleared area and cultivate them for a few years until the soil fertility declines.
- Once the soil becomes less productive, farmers abandon the plot and move on to clear another area, allowing the previously cultivated land to regenerate over time.

2. Small-scale production:
- Shifting cultivation is typically practiced by small-scale farmers who rely on the land to sustain their families.
- The cleared areas are usually small, and the crops grown are primarily for subsistence rather than for sale in markets.
- The focus is on growing enough food to meet the immediate needs of the farmer's family and community.

3. Low input usage:
- Shifting cultivation does not require significant investments in machinery, fertilizers, or pesticides.
- The farming method relies on the natural fertility of the soil and the knowledge and labor of the farmers.
- It is a low-cost form of agriculture that allows farmers to work with minimal resources.

4. Self-sufficiency:
- The primary goal of shifting cultivation is to provide food and other basic necessities for the farmer's family.
- The crops grown are typically diverse, including staple crops like maize, cassava, yams, and beans, as well as fruits and vegetables.
- The surplus produce, if any, may be traded or sold in local markets, but the main focus is on meeting immediate household needs.

In conclusion, shifting cultivation is an example of subsistence farming because it involves small-scale production, low input usage, and a primary focus on meeting the needs of the farmer's family and local community rather than generating profits for commercial purposes.