Question: query regarding use of human excreta in agriculture. 
Answer: you can't use excreta directly in the cultivable field because there are losts of disease causing pathogens are readily available on that excreta. to use this excreta  you have to go through with some laboratory procedures such as sanitization, removal of heavy material and composting etc. after that also you can use this only in flower bed. researchers have not suggest yet to use this excreta in vegetables or other adible products production.