Dear Authors:

Thank you for submitting your replies to reviewer comments. Overall, the reviewers gave affirmative evaluations (fair to good) to your study in terms of scientific significance and quality. One reviewer proposed a bit low evaluation (poor) for scientific significance mainly due to the lack of clear focus, but I believe that you can improve the manuscript by revising it as you responded. I studied your replies and found that you are trying to make the manuscript more focused and sharpened. One reviewer suggested you focus on riparian biogeochemical processes rather than regional and global issues; I agree with your decision for having a clear focus. Also, I appreciate your efforts to add several figures to improve presentation and clarity. As suggested by the reviewers, you should improve Discussion by removing repetitions and adding mechanistic insights (e.g., N2:N2O ratio as you suggested). Finally, I conclude that this manuscript needs major revision, and I would ask the reviewers to examine it after receiving the revised manuscript.

Dear Authors:

Thank you for sending a revised manuscript and your responses to referee comments.
I asked the referees for additional comments and received no critical one.
Also, I studied your revised manuscript and found that it become clearer, for example, by including additional figures and equations, and focused on the main topic.
The title became more appropriate.
Finally, I conclude that the manuscript is acceptable for publication.