Percentage of Nitrogen benefits

Asked October 2, 2020, 9:59 AM EDT

Hi. I am a grade 11 Pure Science student. For my Chemistry subject, I am required to compare and determine the quality of fertilizers based on their percentage by mass of nitrogen. I have picked calcium ammonium nitrate (27%), ammonium sulphate (21%) and carbamide (46%) fertilizers for my comparison project. I have also included the percentages of nitrogen in brackets as above. My question now is that is it better to use a fertilizer that has more nitrogen in them or one with a lower percentage of nitrogen. If a higher percentage is better, could you please explain why? Currently, from my own research, I have found out that plants need nitrogen to help them grow. Hence, my conclusion is that a higher percentage of nitrogen should be better, shouldn't it? Please correct me if I am wrong. However, I do have doubts about my conclusion as there must be some catch as in risks of using huge amounts of nitrogen. Please help me with my confusion. Your help is very much appreciated. Thank you. - Sorfina

Outside United States

3 Responses

Thank you for your question, Sorfina. Any time you are evaluating a 'better' question, I would suggest you must qualify it as 'better for what?' If you use a fertilizer with a higher nitrogen percentage on plants that produce flowers, you may end up with a lot of foliage and few, if any, flowers or fruit, since they require potassium (among others) to fruit. On the other hand, if you have a houseplant that does not flower, the plant's nitrogen needs are greatly increased. That is why we have a variety of fertilizer mixes to be species specific. 10-10-10 (N-P-K) is a balanced fertilizer. But a species may thrive with a 5-10-20 configuration instead. And, depending on species and mode of application, an over application of nitrogen may 'burn the roots' of the plant (a common effect of chicken manure, whose nitrogen is concentrated as urea). The nitrogen will, however, evaporate over 6 months, so that it can safely be used. Fresh manure has an N percentage of 'only' 0.9 to 1.5%! (Compared to 0.4 - 0.5% P and 0.8% K.) I hope this is helpful. Good luck.

Thank you very much! Your response has definitely helped me in my project. Thank you for letting me know that the percentage needed for plants varies on the results i.e. leaves or flowers. Again, your help is appreciated. Thank you and stay safe!!!!

You're most welcome, Sorfina. This may have more information than you need, but....