Why “organic” is not enough. Permaculture is the way to go 🙂 https://www.ncbi.nlm.nih.gov/pubmed/15637215 (nutrient decline from 1950-1990) http://hortsci.ashspublications.org/content/44/1/15.full#xref-ref-12-1 (a bunch of tidbits on soil degredation) https://news.utexas.edu/2004/12/01/nr_chemistry (suggests nutrient decline in crops) Dr. Dave Montgomery on soil degredation Dr. Dave Montgomery on maintaining soil quality http://www.californiaearthminerals.com/media/mineral-nutrient-depletion-in-us-farm-and-range-soils.pdf ( a little tidbit on conventional farming practices) https://you.stonybrook.edu/environment/sustainable-vs-conventional-agriculture/ (tidbits