It's tricky to narrow down soil formation to just two factors, as it's a complex process influenced by many things. However, two of the most significant factors are:

1. Parent Material: This refers to the underlying bedrock or geological material from which the soil develops. The mineral composition, texture, and chemical properties of the parent material strongly influence the soil's own composition and properties. For example, soils derived from limestone will be alkaline, while those from granite will be acidic.

2. Climate: Climate, including temperature and precipitation, plays a crucial role in soil formation. It affects weathering processes, organic matter decomposition, and the movement of water and nutrients within the soil profile. For instance, warm, humid climates promote rapid weathering and decomposition, leading to thick, well-developed soils, while cold, arid climates result in thin, poorly developed soils.

While these two factors are crucial, other factors like organisms (biota), topography, and time are also essential for soil formation.