Differential Responses of Soil Respiration and Its Components to Nitrogen Application in Urban Forests

Round 1

Reviewer 1 Report

The aim of the current research was to evaluate the effects of nitrogen (N) application on soil respiration (Rs) and its components in two urban forests in Hefei, Anhui Province in China. The study is well-written, well-structured, and well-communicated. In general terms, I find the research interesting. I have only a few comments that are described in the following lines.

-        The abstract should be shortened to 200 words maximum, following the journal’s instructions.

-        L21 Please, avoid any examples in the abstract section.

-        L111 The canopy closure is estimated at plot/stand level, not tree level. I suggest correcting the expression.

-        L111 How the canopy closure was estimated? Is it a canopy cover instead?

-        L164 I suggest revising to “not met” instead of “false”.

-        L168-169 Which blocking factor was used in order to develop a mixed-effect model? Please explain briefly why this kind of analysis was selected. In addition, please mention the software used.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The question arises as to how changing environmental conditions may affect N deposition Do prolonged droughts lead to plant nitrogen deficits and reduced root activity?
And how should the effects of N uptake by plants and their associated microorganisms be interpreted? More than 70% of carbon is transferred from tree canopies to root systems, where it is used by fungi that form mycorrhizal communities with roots. Not only they take up C into the mycelium, but nematodes, mites and other organisms also take up C into their bodies. How does this affect the balance or CO2 emissions of the soil? Are these processes inhibited during periods of drought and accelerated during periods of high moisture? In addition to the mycelial network that connects living plants, there is another that connects dead organic material, which in turn leads to decomposition and the release of CO2 into the atmosphere. Has this also been taken into account? What is the relationship of N deposition to other elements, such as P and S? P as a vital element influences root development, and root activity and the rhizosphere in turn determine CO2 uptake and excretion; will the authors consider this aspect in future studies?

Author Response

Please see the attachment.

Author Response File: Author Response.docx