Fertigation Strategies to Improve Water and Nitrogen Use Efficiency in Surface Irrigation System in the North China Plain
, Yizan Li 3, Marius Heinen 4, Henk Ritzema 2, Petra Hellegers 2 and Jos van Dam 5Round 1
Reviewer 1 Report
Dear Authors
The manuscript's subject is interesting and its text is clear, well presented and structered. However some modifications/improvements should be madae, as follows:
1) Please, rewrite the first lines of the Abstract and Introduction - No need to say that irrigation and fertilization increase crop yield. Everybody knows.
2) The key-words should not include wods of the title. Those words should be substituted.
3) Fertigation is the injection of fertilizers into an irrigation system. So, you should substitute the word "fertigation", according to the fertilization parctice you have used.
4) It is known that surface irrigation systems have lower irrigation efficiencies. So, you should mention its value, and also inform on the uniformity of the irrigation water distribution.
Author Response
Point 1: Please, rewrite the first lines of the Abstract and Introduction - No need to say that irrigation and fertilization increase crop yield. Everybody knows.
Response 1: Thanks for the advice. The first sentences were modified in the text.
Point 2: The keywords should not include words of the title. Those words should be substituted.
Response 2: Thanks for the suggestion. The keywords were replaced by “Surface fertigation; Topdressing; Field experiment; SWAP-WOFOST-N”.
Point 3: Fertigation is the injection of fertilizers into an irrigation system. So, you should substitute the word “fertigation”, according to the fertilization practice you have used.
Response 3: Thanks for the comment. Surface fertigation is one approach of the fertigation technique, and we applied it for topdressing urea in the field experiment. Thus, the word “fertigation” is suitable in most lines. Maybe we can delete the word in the title?
Point 4: It is known that surface irrigation systems have lower irrigation efficiencies. So, you should mention its value, and also inform on the uniformity of the irrigation water distribution.
Response 4: Indeed, I added more information on these values. See details in lines 385-387 and line 595.
Reviewer 2 Report
The study appears to have been carefully conducted and the manuscript is clearly and concisely written. Suggested edits are in the attached file.
Comments for author File: 
Comments.pdf
Author Response
Point 1: Text editing
Response 1: Thanks for all the suggestions. I modified the whole paper based on your advice.
Point 2: in Line 615: couldn’t this be because maize is C3 and more efficient vs. wheat rather than over-irrigation?
Response 2: Good point. I think the conclusion was misdescribed here as I want to say the WUE for wheat and maize are both low. Thus, I rewrote the sentence as in lines 623-624.
