I don't know if I believe that it doesn't have stuff plants need in it.
The whole sacramento Valley is one giant silt bed, it is the best place in the USA to grow food because of it.
Food Can't grow well without trace nutrients. Salmon from the ocean bring back elements from the ocean that you can not get anywhere else. Fish are harvested, and it used to be, scattered all around the forest making great nutritious soil. The rain comes, and washes all those nutrients down streams and rivers ending up on lakes and valleys.
I just think maybe there is more to this story, don't mean to ruffle feathers.
Peace
Eek