What are the five main factors of soil formation? explain how each one contributes to soil profile development.

The five main factors of soil formation are: Parent Material, Climate, Living Organisms, Landscape Position and Time. 

1. Parent Material: Parent Material refers to the organic and mineral material where soil formation begins. 

2. Climate: Climate determines the rate of weathering through it's influence on the temperature of the soil. 

3. Living Organisms: Animals living in the soil affect decomposition of waste materials and how soil materials will be moved around in the soil profile.

4. Landscape: The type of landscape also effects soil formation. Uplands, Depression and Floodplain are examples of landscapes. 

5. Time: The longer a soil has gone through weathering, the more the natural changes occur to that area.

your answer is "the 1950's"