The statement is - true.
This fine-grained light coloured accumulation of silt and clay particles that is deposited by the wind contributes to fertilizing the soil. The fact that it is very small sendy particles in question, it gets mixed with the organic matter very easily and it makes fertile nice soil suitable for multiple cultures. Maybe the best example of this is the connection between the Sahara desert and the Amazon rainforest, where the winds take loess from Sahara and take it over the Atlantic Ocean to deposit it in the Amazon rainforest in South America, and this loess is essential for the survival of the rainforest as it is the biggest fertilizer the rainforest gets every year.
