I think modern farmers don't really have much of a problem re-introducing depleted nutrients into the soil. Modern fertilizers, composting, and amending soil ar

I think modern farmers don't really have much of a problem re-introducing depleted nutrients into the soil. Modern fertilizers, composting, and amending soil are pretty well understood farming and gardening techniques. The fact that every year, literally thousands of tons of nutrients in the form of salmon from the ocean makes its way upstream, where it just deposits itself and stays there probably helps a lot. All the local plants are benefiting from this annual nutrient bomb.