Dear PF Forum, My church concerns about climate change/global warming condition now. And we try our best to cope (altough in a very small scale) to lessen the effect. Now, I'd like to know about composting. But I have no idea what to do. What stages are there in composting What kind of bacterias are there in bioactive compound involved in composting process. How to grow/harvesting the bacteria in bioactive compound. What is the end product and the usefulness of composting end product, etc... Perhaps I should begin from the end and work my way up in subsequent postings The end product of composting is fertilizer, and I'd like to know what elements are in a plant. I try to find links that explains the elements composition in a plant, but it's difficult, instead I found this link https://en.wikipedia.org/wiki/Composition_of_the_human_body The elements composition human body are (in mass) Oxygen 65% Carbon 18% Hydrogen 9% Nitrogen 3.2%, and also phosporus, calcium, potassium, sulfur etc.. 1. Is it safe to assume that the elements compositions in plants roughly resembles those in human body? Some 30 years ago when I was in junior high, I once read that someone conducted an experiment. He/She grew a plant from a pot bucket filled with soil. All he/she did was only watering the pot. And when the plants grow bigs, the soil was measured. The mass of the soil decreased very little. IF the CHON composition (Carbon, Hydrogen, Oxygen, Nitrogen) in living organism is roughly 95% (since I don't know the answer of question number 1)... Was the experiment possible? It's been a long time ago that I read the article. 2. Is it true that plant gets their Oxygen from air Carbon from CO2 Hydrogen from water Nitrogen from air? 80% in atmosphere ------------------------------------------------------------------- So here are the gist of my questions. 1. Is the element composition in plants roughly resembles that in human body? 2. Is it true that plants gets their Oxygen from air Carbon from CO2/air Hydrogen from water Nitrogen from air? Thanks for any replies.