The authors have provided a very readable and comprehensive state-of-the art on major terrestrial N inputs. I deeply appreciate the referees’ extensive plea for improvements to the original paper and the authors’ clear responses. The main criticism raised was that there would have been benefit in deviating from the current system to include rock weathering in this new discussion / overview paper of N inputs in terrestrial ecosystems. I believe the authors have a profound insight in the subject at hand and were well placed to decide to what extent they were prepared to restructure all into a process-based discussion. The authors have chosen to keep the current state-factor based structure and have well motivated this decision. I follow the main reasoning that there is benefit to now place N in a similar lens as P, cations and other elements. Still, it is indeed appropriate to acknowledge that the state factor approach is also a limiting mold. It is not entirely convenient to address interactive effects of multiple state factors on weathering, deposition and fixation. However, I don’t either immediately see how such could be avoided by the alternative process-based structure. For instance, in such a discussion climate effects on these three groups of processes would still be dispersed over several sections. To my feeling, it would never be possible to quantatively discuss all possible interactive effects of state-factors on N-input processes in a single paper. Ideally I would follow the referees’ idea to have both state-factor and process-based approaches in this manuscript, but at the same time see that this would involve repetition and render this discussion paper too long. Regardless, the authors did well in further acknowledging any shortcomings of the state-factor-approach throughout the text. The authors and referees already did engage in a mature and open discussion. I have no further suggestions to improve the current manuscript and support its publication as is.
AE Steven Sleutel

I would like to thank the authors for their engagement in a healthy and constructive discussion with the reviewers. I think it will help the readers to understand how and why certain things are tackled in the paper and other things are not.
Thanks for a superb review.
Jo