Crop Yield, Nitrogen Recovery, and Soil Mineral Nitrogen Accumulation in Extremely Arid Oasis Cropland under Long-Term Fertilization Management
Round 1
Reviewer 1 Report
This paper aimed to optimize fertilizer application, increase productivity and nitrogen use efficiency in grey desert soils from a long-term perspective. Only a few continuous long-term studies have been conducted on the oasis grey desert soil. So, it’s an interesting and important study. However, it is subjected to improvement before it is acceptable for publication with due attention to the following weakness.
- Line 50: Authors should add the unit after “80”.
- Line 119: Soil pH is closely related with the ratio of water and soil. Please give the ratio of water and soil.
- Line 181: There seems a mistake in equation (2). Please check.
- Line 243: Not only in 2013. Please revise.
- Line 363: Here should be high carbon: nitrogen (C/N)？
- Lack of spaces between numbers and units/words in some places in the manuscript.
Author Response
-
Dear editors and reviewer:
Many thanks for you careful review of our manuscript, and give us valueable and helpful comments. Revised portion are marked in red and as follow:
Comments and Suggestions for Authors
This paper aimed to optimize fertilizer application, increase productivity and nitrogen use efficiency in grey desert soils from a long-term perspective. Only a few continuous long-term studies have been conducted on the oasis grey desert soil. So, it’s an interesting and important study. However, it is subjected to improvement before it is acceptable for publication with due attention to the following weakness.
- Line 50: Authors should add the unit after “80”.
Response: Thanks for your suggestion, we have revised it.
- Line 119: Soil pH is closely related with the ratio of water and soil. Please give the ratio of water and soil.
Response: The ratio of water and soil is 1:1, we added it into manuscript.
- Line 181: There seems a mistake in equation (2). Please check.
Response: Thanks for your carefully check, we have revised the equation(2) in section 2.3.
- Line 243: Not only in 2013. Please revise.
Response: Revised as suggested.
- Line 363: Here should be high carbon: nitrogen (C/N)？
Response: Revised as suggested.
- Lack of spaces between numbers and units/words in some places in the manuscript.
Response: Revised as suggested.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This manuscript contains important issues regarding nitrogen management in crop production. Please review the following comments and revise this manuscript:
The abstract lacks information on abbreviations for the reader, it is difficult to quickly understand what the conditions of the experiment are.
In line 107 ,,… approximately 2570 mm and mean annual temperature is 7.7℃(Figure 1)…’’.
Figure 1 shows the evaporation scale up to 300 mm, the evaporation information given is 2750 mm, this should be clarified.
In rows 132 - 133 the unit of fertilizer application is unclear.
,,…NPKM+: 164 kg N ha-1yr-1 as urea, 40.2kg P ha-1yr-1 as calcium superphosphate and 32.6 132 kg K ha-1 a-1 as potassium sulfate…’’.
Spaces are missing from many lines in the text … e.g. 119 “K contents of 9,and 505 mg kg-1”, in line 124, 127, 131, 135…etc.
In table 2 there is a strength unit K2O/ hm2, it is hard what means this unit, it should be explained.
In line 181 the equations 1 through 3 are difficult to understand, “… Plant N (kg N ha-1) derived from fertilizer treatment (Ndff)=N uptake by plant ×15N atom% excess in plant/ 15N atom% excess in fertilizer…”, the way of Plant N derived from fertilizer is unclear, what is 15N atom% excess in plant and what is 15N atom% excess in fertilizer? I am not able to calculate this parameter, it should be presented in a clearer way.
Include information about replications in Section 2.5, Statistical Analysis.
In figure 2 lacks data from the ANOVA analysis, the error bars do not allow for a significant difference between fertilizer treatments in each year ...
The title of figure 2 :” Figure 2. Aboveground biomass (grain and straw yields) of spring wheat, winter wheat, and summer maize under long-term fertilization in 2013” is inadequate, there is a lack information about the maize, winter and spring yield. The title should be improved as follows: Effect of fertilizer treatments on plant yield and aboveground biomass ....., 1990-2013.
In figure 3 there is a lot of data overlapped, it should be presented in more clear way.
In Table 4, the abbreviation Kg ha-1 should be corrected to kg ha-1.
In tables and figures with the results there is CK treatment, but no information about this is included in the chapter 2.2 Long-term experiment, it is necessary to describe it.
In lines 226- 229 “…Furthermore, a comparison of the CV of the treatments showed that NPKM and NPKM+ did not differ significantly in the wheat season but were relatively lower for NPKM+ treatment in the maize season (p>0.05)..."
Inconsistency appears in the manuscript as the CV value for NPKM and NPKM+ is 27.1 and 43.2 for maize, respectively, the value for NPKM is higher than for the NPKM+ combination.
In lines 229- 230, the CV value for NPKM treatment is higher than for NPK treatment in spring wheat season. It should be corrected.
Author Response
Dear editors and reviewer:
Many thanks for you careful review of our manuscript, and give us valueable and helpful comments. Revised portion are marked in red and as follow:
Comments and Suggestions for Authors
This manuscript contains important issues regarding nitrogen management in crop production. Please review the following comments and revise this manuscript:
The abstract lacks information on abbreviations for the reader, it is difficult to quickly understand what the conditions of the experiment are.
Response: Thanks for you suggestion, we have revised related abbreviations to make more clearly for readers.
In line 107 ,,… approximately 2570 mm and mean annual temperature is 7.7℃(Figure 1)…’’.
Figure 1 shows the evaporation scale up to 300 mm, the evaporation information given is 2750 mm, this should be clarified.
Response: The 2570mm represents the annual total evaporation.
In rows 132 - 133 the unit of fertilizer application is unclear.
,,…NPKM+: 164 kg N ha-1yr-1 as urea, 40.2kg P ha-1yr-1 as calcium superphosphate and 32.6 132 kg K ha-1 a-1 as potassium sulfate…’’.
Response: Thanks for your suggestion, we have revised this sentence
Spaces are missing from many lines in the text … e.g. 119 “K contents of 9, and 505 mg kg-1”, in line 124, 127, 131, 135…etc.
Response: Revised as suggested
In table 2 there is a strength unit K2O/ hm2, it is hard what means this unit, it should be explained.
Response: Thanks for you suggestion, we have changed the hm2 into ha-1.
In line 181 the equations 1 through 3 are difficult to understand, “… Plant N (kg N ha-1) derived from fertilizer treatment (Ndff)=N uptake by plant ×15N atom% excess in plant/ 15N atom% excess in fertilizer…”, the way of Plant N derived from fertilizer is unclear, what is 15N atom% excess in plant and what is 15N atom% excess in fertilizer? I am not able to calculate this parameter, it should be presented in a clearer way.
Response: Thanks for your suggestion, we have revised these equations.
Include information about replications in Section 2.5, Statistical Analysis.
Response: Revised as suggested
In figure 2 lacks data from the ANOVA analysis, the error bars do not allow for a significant difference between fertilizer treatments in each year ...
Response: Figure 2 mainly describes the trends of crop yield and aboveground biomass in the past 23 years. Considering that Table 3 has overall yield analysis, we deleted the error bar in fig.2.
The title of figure 2 :” Figure 2. Aboveground biomass (grain and straw yields) of spring wheat, winter wheat, and summer maize under long-term fertilization in 2013” is inadequate, there is a lack information about the maize, winter and spring yield. The title should be improved as follows: Effect of fertilizer treatments on plant yield and aboveground biomass ....., 1990-2013.
Response: Revised as suggested
In figure 3 there is a lot of data overlapped, it should be presented in more clear way.
Response: We have revised this fig.
In Table 4, the abbreviation Kg ha-1 should be corrected to kg ha-1.
Response: Revised as suggested
In tables and figures with the results there is CK treatment, but no information about this is included in the chapter 2.2 Long-term experiment, it is necessary to describe it.
Response: We have changed the control into CK in Section 2.2
In lines 226- 229 “…Furthermore, a comparison of the CV of the treatments showed that NPKM and NPKM+ did not differ significantly in the wheat season but were relatively lower for NPKM+ treatment in the maize season (p>0.05)..."
Response: Thanks for your suggestions, we have revised this sentense.
Inconsistency appears in the manuscript as the CV value for NPKM and NPKM+ is 27.1 and 43.2 for maize, respectively, the value for NPKM is higher than for the NPKM+ combination.
Response: Revised as suggested
In lines 229- 230, the CV value for NPKM treatment is higher than for NPK treatment in spring wheat season. It should be corrected.
Response: Revised as suggested
Author Response File: Author Response.docx
Reviewer 3 Report
The paper can of great interest for the scientific community, responding to the challenge of growing crops in arid climate using new technologies
Author Response
Dear editors and reviewer:
Many thanks for you comments！
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
