Theres probably liquid concentrate products that are organic and 100 percent bone meal or atleast majorly and still completely organic. Also you could easily make a "tea" or extract by using 1 teaspoon per gallon I believe. As far as adding it to the top I think you CAN do it not sure how that works exactly but I'm fairly certain it can be done.

As far as the poison ivy grows, its only absorbing things from the soil its not really releasing anything harmful into the environment. I'm not sure what effect the oil that poison ivy produces would have on your plant but I'd imagine it possibly could burn/damage/stress the plant somehow creating more problems later on. Don't know for sure but I couldn't picture anything beneficial coming from it that's for sure.

As far as health effects goes as as to smoking a product that came into contact with it, I really woulden't suggest it but I doubt it would have a serious effect unless the poison ivy is actually constantly rubbing against it. You should put some gloves on and a sweatshirt with pants and attempt to to remove any nearby ivy plants.