That site seems to address most of the issues on this site around beans, squashews and corn!!!!
I thought the native indians were organic until I read page 117 on horse and cow dung - "we did not like to have any dung on our garden lands, and we therefore removed it (we carefully cleaned off the dried dung, picking it up by hand and throwing it ten feet or more beyond the edge of the garden plot :o)" the reason being that it caused the weeds to grow -
"Now that white men have come and put manure on their fields, these strange weeds brought by them have become common. In old times we Hidatsas kept our gardens clean of weeds. I think this is harder to do now that we have so many more kinds of weeds." - this I can relate to!!