Evaluation of Nitrogen Fertilization Systems Based on the in-Season Variability in the Nitrogenous Growth Factor and Soil Fertility Factors—A Case of Winter Oilseed Rape (Brassica napus L.)
Round 1
Reviewer 1 Report
Dear authors,
Whole manuscript is too long, it shold be more concise.
Abstract- abbreviations like BBCH should be explained or not mentioned
Introduction
Line 28 – 38 – this paragraph is like introduction to plant nutrition. Readers of this journal already know that information. Please remove or put 1 or 2 sentences.
Line 42-43 – is this true for all species, some prefer ammonium.
Line 48-54 – this paragraph repeat some issues allready mentioned in previous one. You should merge it.
Line 63-81- paragraph is too wordy, please shorten it and keep it simple and left only issues important for this manuscript.
BBCH give full name
Line 87 – 94 – it seems like you here give results,but like in the Results section and not like in the Introduction where you should summarize previous work in article 33, you need to rewrite it.
M&M section
Line 125 – you explain results of available nutrients and you repeat it in Table 1. Leave only one.
Similar with table 2, just put: Climate data are in Table 2., do not repeat numbers.
Line 147_ Sentence should be more like: WOSR cultivar (variety') Impression was used as hybrid …. English should be checked by native English speaker
Line 180 – 194 – put only why you did PCA, we do not need in scientific journal paragraph about PCA, that is for book chapter or Wikipedia.
Results
Table 3. standard is to put significance letters – a for highest values,c for lowest. Change through whole manuscript.
Normally when you have statistically significant interactions, you do not interpret the main effect even put all these values in Table 3.
I prefer to made only table with significances and not all values. Most important interactions (yield and one or two more should be made in graphs) and FIg. 2-4 I will put in Suplementary.
It is very hard to read so long results, it should be more concise, even to remove part of the data from tables and text.
Disscussion
It is too descriptive, some sentences are more suitable for results.
When authors explain results there should be some connections with possible mechanisms responsible for it, not just link with previous results.
Author Response
Reviewer 1
Dear authors,
Whole manuscript is too long, it shold be more concise.
A manuscript has been substantially corrected:
1) Some parts of Introduction, being in the opinion of both reviewers weakly related to the key topic, have been removed from the text.
2) There has been added a part about sources of nitrogen, focusing on digestate as a potential substitute of mineral N fertilizers.
3) All Figures related to variables distribution on PCA axes have been moved to supplementary material.
- Table A5 has been removed from the text.
- Some parts/sentences of the Results sections have been removed from the text.
- Discussion has been significantly shortened:
- figure 7 has been removed from the test; the regression models obtained have been moved to the Results section;
- some parts weakly related to the main topic have been removed from the text.
Abstract- abbreviations like BBCH should be explained or not mentioned
Abbreviations, like BBCH, have been explained, when they were used the first time in the text.
Introduction
Line 28 – 38 – this paragraph is like introduction to plant nutrition. Readers of this journal already know that information. Please remove or put 1 or 2 sentences.
The main objective of this part was to introduce a reader to the concept of a Nitrogenous Growth Factor as related to the action of nitrate nitrogen and to Fertility Factors as related to indicators of soil fertility.
This part of Introduction has been substantially corrected.
Line 42-43 – is this true for all species, some prefer ammonium.
We agree with the reviewer’s opinion, but high-yielding crops, like winter oilseed rape, respond significantly (yield), to N-NO3 as the main N form.
Line 48-54 – this paragraph repeat some issues allready mentioned in previous one. You should merge it.
This part has been corrected, and the repeated parts have been substantially changed or removed from the text.
Line 63-81- paragraph is too wordy, please shorten it and keep it simple and left only issues important for this manuscript.
This part of Introduction has been substantially changed.
BBCH give full name
All abbreviations, like BBCH have been explained, when used the first time in the text.
Line 87 – 94 – it seems like you here give results,but like in the Results section and not like in the Introduction where you should summarize previous work in article 33, you need to rewrite it.
This part has been shortened to one sentence, relating to the trend of N accumulation by the high-yielding WOSR.
M&M section
Line 125 – you explain results of available nutrients and you repeat it in Table 1. Leave only one.
It has been corrected in accordance to the Reviewer’s suggestion.
Similar with table 2, just put: Climate data are in Table 2., do not repeat numbers.
The repeated numbers do not refer to the whole growing season of WOSR. They summarize meteorological conditions of this crop during the spring part of its vegetation. The spring precipitations are the key factor for WOSR growth and yielding in the Central Europe.
Weymann, W., Bottcher, U., Sieling, K., Kage, H. Effects of weather conditions during different growth phases on yield formation of winter oilseed rape. Field Crops Res. 2015, 173, 41-48.
Line 147_ Sentence should be more like: WOSR cultivar (variety') Impression was used as hybrid …. English should be checked by native English speaker
The whole text has been corrected by English native speaker Mr. Robert Kippen, at present lecturer at Adam Mickiewicz University in Poznan, Poland.
Line 180 – 194 – put only why you did PCA, we do not need in scientific journal paragraph about PCA, that is for book chapter or Wikipedia.
It has been corrected in accordance to the Reviewer’s suggestion.
Results
Table 3. standard is to put significance letters – a for highest values,c for lowest. Change through whole manuscript.
It has been corrected in accordance to the Reviewer’s suggestion.
Normally when you have statistically significant interactions, you do not interpret the main effect even put all these values in Table 3.
I prefer to made only table with significances and not all values. Most important interactions (yield and one or two more should be made in graphs) and FIg. 2-4 I will put in Suplementary.
Data presented in table 3-6 contains a lot of information, which are significantly related to impact of years. The description of the main effects has been substantially shortened. Figures 3-6 are the core of the study, explaining both nitrate N and other nutrient status in cardinal stages of WOSR growth (Figures 3 and 5). The Figure 4, presenting the change in the N-NO¬3 content during the stem elongation phase (STME), in fact, indirectly shows the mechanism of N uptake by WOSR with respect to its primary source.
All Figures related to the distribution of soil fertility variables on PCA axes have been moved to supplementary material.
It is very hard to read so long results, it should be more concise, even to remove part of the data from tables and text.
Some parts of the Results section have been, as described above, substantially corrected.
Disscussion
It is too descriptive, some sentences are more suitable for results.
The Discussion section has been substantially changed. Some parts weakly related to the main topic or being significantly related to the Results section, have been corrected.
When authors explain results there should be some connections with possible mechanisms responsible for it, not just link with previous results.
In both sections, i.e. Results and Discussion, the obtained dependencies were directly confronted with the available literature data. The key weakness in the conducted study was a shortage of respective reference materials. Except of some studies on N and some other nutrients uptake (P, K, Mg, Ca) by oilseed rape there are no referenced data on simultaneous changes of this set of nutrients in the soil, taking into account the cardinal stages of growth. The mechanism of nitrate N (NN) uptake is best presented in Figures No. 4 and 7. It is clearly shown that the seemingly loss of NN in the soil is due to its uptake by WOSR. This study clearly showed that the NN loss of about 120 kg ha-1 during the STME resulted in the highest yield.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In general, the paper is quite interesting and well organized. It reports full field experimentation and a very detailed statistical treatment of the data.
However, the introduction (lines 28-81) must be completely revised as it contains known information, sometimes obvious, while it should focus attention on the differences between mineral fertilization versus organic fertilization as a key to maintaining soil fertility and productivity of the plants.
Table 2 is inultile.
Furthermore, the characteristics of the soils should be reported, in the M&M section, in the same paragraph with a summary table. Delete from Table 1 Fe Mn Zn Cu because then they are not commented.
Line 124 deep 0.3-0.6 is repeated while 0.6-0.9 is missing
Complete the Founding and Acknowledgments sections, otherwise remove.
Author Response
Reviewer 2
Comments and Suggestions for Authors
In general, the paper is quite interesting and well organized. It reports full field experimentation and a very detailed statistical treatment of the data.
However, the introduction (lines 28-81) must be completely revised as it contains known information, sometimes obvious, while it should focus attention on the differences between mineral fertilization versus organic fertilization as a key to maintaining soil fertility and productivity of the plants.
1) Some parts of the Introduction, being too academic in the opinion of the reviewer, have been removed from the text.
2) There has been added an extensive part about sources of nitrogen, focusing on digestate as a potential substitute of mineral N fertilizers.
The main corrected text is shown below.
The key sources of N in intensive crop production are mineral N fertilizers (Nf) [1, 3]. Consumption of Nf has progressively increased during the last hundred years, and it is expected to have increased up to 182 mln t by 2050, i.e. 75% more as compared to 2010 [30]. Some of the projected Nf consumption can be potentially substituted by other N sources, mainly organic by-products (wastes) of human activity [31, 32]. As a fast-developing source of renewable energy, biogas plants seem to be a great source of N which could be used in crop production. The by-product of the anaerobic digestion is digestate, which is rich in mineral and organic N compounds. However, its concentration in raw biogas slurry is highly variable both in total content (0.1 – 0.5% fresh weight) and in ammonium (30 to 70% of total N) [33, 34]. Digestate, depending on the substrate, also contains other nutrients (macro-, and micronutrients), as well as enzymes and hormones. All these compounds significantly affect the level of soil fertility, including the content of soil available N, and in consequence affect plant growth and yield [35, 36]. However, a key question remains respecting the efficiency of biogas N in crop production in comparison with the classical N source, i.e. to Nf. The latest study on maize response to digestate showed higher its efficiency, i.e. a net yield increase as compared to ammonium nitrate [37].
Table 2 is inultile.
The growing season of winter oilseed rape starts in late summer (August) the previous year and ends in July, the next year. Basic data, i.e. precipitation and temperatures presented in Table 2, covers the whole growing season.
Furthermore, the characteristics of the soils should be reported, in the M&M section, in the same paragraph with a summary table. Delete from Table 1 Fe Mn Zn Cu because then they are not commented.
Table 1 has been corrected, i.e. data about micronutrients has been removed.
Data presented in Table 1 shows the fertility status of soil with respect to main nutrients at the experiment set up, i.e. before sowing (August 2015 and 2016, respectively). Data presented in Tables 3, 4, 5 show the status of available P, K, Mg, Ca contents within the WOSR growing season, i.e. i) at the rosette stage, i) the onset of flowering, iii) the physiological maturity.
Line 124 deep 0.3-0.6 is repeated while 0.6-0.9 is missing
It has been corrected.
Complete the Founding and Acknowledgments sections, otherwise remove.
This part was removed from the text.
Author Response File: Author Response.pdf
