Unfortunately there is now a lot of information/misinformation available to consumers about gardening practices. Some of these ideas are not based on science and frustrate me to no end. One of my favorite sources for information is The Garden Professors. Their mandate is to provide research-based information on creating and sustaining gardens and landscapes to the general public. I will direct you to their blog on amending soil for more information on this topic.
Amending Soils - Why??