The Productivity and Nutrient Use Efficiency of Rice–Rice–Black Gram Cropping Sequence Are Influenced by Location Specific Nutrient Management

Round 1

Reviewer 1 Report

Reviewer Comment to manuscript sustainability-1112552

[Site-specific nutrient management determines the productivity and nutrient use efficiency under rice–rice–black gram cropping system]

 

The subject of the work is interesting about the high practical use (especially in areas where research was conducted).

The research was carried out well and the conclusions drawn are directly derived from the results.

Below are some minor comments

In the formula for LAI: in the denominator should be “ground area”.

In the title table 10 to change (g) to (t/ha).

Author Response

Response to Reviewer_1 comments

 

Comments and Suggestions for Authors

Reviewer Comment to manuscript sustainability-1112552

[Site-specific nutrient management determines the productivity and nutrient use efficiency under rice–rice–black gram cropping system]

 The subject of the work is interesting about the high practical use (especially in areas where research was conducted).

Authors’ reply: Thank you very much for your valuable comments.

The research was carried out well and the conclusions drawn are directly derived from the results.

Authors’ reply: Thanks a lot for your evaluation.

Below are some minor comments

In the formula for LAI: in the denominator should be “ground area”.

Authors’ reply: Extremely sorry. It has been corrected.

In the title table 10 to change (g) to (t/ha).

Authors’ reply: Extremely sorry. It has been corrected.

 

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript entitled: Site-specific nutrient management determines the productivity and nutrient use efficiency under rice–rice–black gram cropping system” presents study on optimized fertilization of rice.

The manuscript is quite well prepared but contains some drawbacks. Below are detailed comments:

1) NUE acronym is used for both “nitrogen use efficiency” (line 96) and “nutrient use efficiency” (line 110). It would be better if you use that acronym only for one meaning to avoid misunderstanding.

2) Please use soil classification type according FAO (World Reference Base for Soil Resources) for description of soils in the experiments.

3) It would be good if approximate geographical coordinates of location of the experiments will be presented.

4) Please provide more details about ANOVA model (factors) used for statistical analyses.

5) Line 144: How many blocks/replications?

6) Table 2: Please add units for EC

7) What does it mean SEm in tables 4-10? The same question for acronym CD. It should be clearly stated. Tables and figures should be self-explanatory. Did you apply multiple comparisons procedure for comparison of means? It is not clear which means are statistically different.

8) Fig. 2-4: I propose to change layout of the Fig. 2, 3, 4 because cumulative columns is in my opinion not clear. I suggest to present columns one each next to other to allow more clear comparisons. Moreover columns for pooled means should be added. Please explain what error bars in the figure mean.

9) Fig. 5-8: What is presented as one point in the Fig. 5-8? There is quite small number of points. I suggest to present as individual point one plot (not averaged value).

10) Site specific nutrient management is very often synonymous with precision agriculture where nutrient fertilization is adjusted to soil fertility and crop needs. The experiment had a rather little association with SSNM. The conducted experiments, in my opinion, can not be called SSNM experiment. The doses of nutrients were not adjusted to content of nutrients in soil. There were many different treatments which were evaluated regardless of soil fertility before fertilization. I suggest to change the title of the manuscript to avoid SSNM or provide more proofs that fertilization treatments were adjusted to soil fertility before fertilization and needs of the crop.

             

 

 

 

 

 

 

Author Response

Response to Reviewer_2 comments

 

Comments and Suggestions for Authors

The manuscript entitled: Site-specific nutrient management determines the productivity and nutrient use efficiency under rice–rice–black gram cropping system” presents study on optimized fertilization of rice.

The manuscript is quite well prepared but contains some drawbacks. Below are detailed comments:

• NUE acronym is used for both “nitrogen use efficiency” (line 96) and “nutrient use efficiency” (line 110). It would be better if you use that acronym only for one meaning to avoid misunderstanding.

Authors’ response: Corrected.

• Please use soil classification type according FAO (World Reference Base for Soil Resources) for description of soils in the experiments.

Authors’ response: Corrected, made soil type as Ultisols.

• It would be good if approximate geographical coordinates of location of the experiments will be presented.

Authors’ response: Thank you for your comments. Geographical locations of experimental site in longitude and latitude have been mentioned.

• Please provide more details about ANOVA model (factors) used for statistical analyses.

Authors’ response: A. Thank you for your comments. In this regard we would like to mention that in the subheading 2.2, the treatments and experimental design adopted have been discussed. Following is for your reference.

2.2 Experimental treatments and design

The experiment was conducted for two years (six cropping seasons) during 2013-14 and 2014-15. The experiment was laid out in Randomized Block Design with nine treatments (10m x 10m plots). The following treatments were set: T₁: ample dose of N, P, K, S and Zn; T₂: P, K, S and Zn, T₃: N, K, S and Zn; T₄: N, P, S and Zn; T₅: N, P, K and Zn; T₆: N, P, K and S, T₇: local variety under the unfertilized check; T₈: local variety under ample fertilizer; T₉: control (without any fertilizer). The ample dose of N, P and K were calculated on the basis of yield targets that were 5 t ha^-1 and 7 t ha^-1 in kharif and boro seasons, respectively. The dose of nutrients in T₁ was 150:60:70 kg ha^-1 of N: P₂O₅: K₂O and 200:80:90 kg ha^-1 of N: P₂O₅: K₂O in kharif and boro seasons, respectively.

2. Further, in the subheading 2.5, the statistical analysis has been addressed and software used has been mentioned.

 

2.5 Calculations and statistical analysis

The experimental data were analyzed statistically by using analysis of variance (ANOVA). The significance of variance was determined by ‘F test’ at 5 percent level of significance [26]. The Excel software (Microsoft office Home and Student version 2019-en-us, Microsoft Inc., USA) was used for statistical analysis, drawing of graphs and figures.

 

• Line 144: How many blocks/replications?

Authors’ response: Thank you very much for your comments. The experiment was carried out with three replications in each location. It has been corrected. (Ref. Line no. 146)

• Table 2: Please add units for EC

Authors’ response: Thank you. It’s a mistake and corrected. (Ref. Table 2)

• What does it mean SEm in tables 4-10? The same question for acronym CD. It should be clearly stated. Tables and figures should be self-explanatory. Did you apply multiple comparisons procedure for comparison of means? It is not clear which means are statistically different.

Authors’ response: Thank you for your suggestion. It has been included in the subheading 2.5.

• 2-4: I propose to change layout of the Fig. 2, 3, 4 because cumulative columns is in my opinion not clear. I suggest to present columns one each next to other to allow more clear comparisons. Moreover columns for pooled means should be added. Please explain what error bars in the figure mean.

Authors’ response: Thank you for your valuable remarks. We have changed the layout of Figures 2, 3, & 4, based on your suggestion

• 5-8: What is presented as one point in the Fig. 5-8? There is quite small number of points. I suggest to present as individual point one plot (not averaged value).

Authors’ response: Based on your suggestion, we have been also revised Figures 5, 6, 7 & 8 for better understnding

10) Site specific nutrient management is very often synonymous with precision agriculture where nutrient fertilization is adjusted to soil fertility and crop needs. The experiment had a rather little association with SSNM. The conducted experiments, in my opinion, can not be called SSNM experiment. The doses of nutrients were not adjusted to content of nutrients in soil. There were many different treatments which were evaluated regardless of soil fertility before fertilization. I suggest to change the title of the manuscript to avoid SSNM or provide more proofs that fertilization treatments were adjusted to soil fertility before fertilization and needs of the crop.

Authors’ response: Thank you for your valuable suggestion. Since the trial was done in multiple locations. So, the title may be as: ‘The Productivity and Nutrient Use Efficiency of Rice–Rice–Black Gram Cropping Sequence are Influenced by Location Specific Nutrient Management’

 

Author Response File: Author Response.docx

Reviewer 3 Report

The paper is an interesting research on the effect of fertilizer applications on plant growth. It is well written and fit the journal scoop. However, based on the description of the experimental design and the presentation of the data, it seems that no replicate was made for each treatments. For me, this is the most negative aspects of the research ! How can it be possible to draw conclusion based only on 1 observation ?! The second negative aspect of this study is the lack of discussion of the results.

 

Figure 1 : I think the point for the relative humidity are misplaced, they are below the 0 line. Add the units on the axe labels. Write the °C properly.

Table 1: please give a brief description of the methods used.

Materials and Methods, section 2.2: you state that in T1, ample dose of N, P, K, S and Zn were applied; but you do not specify if it is a regular dose or an ample dose of the diverse elements in the other treatments. Please specify.

Section 2.4.1: you sampled the plant in different rows for diverse analyses… how can be sure that there was no row effect due to the heterogeneity of the soil ? Why did you not sampled the plants randomly in the all plot ?

In the LAI formula, I think there is a spelling mistake, it should be ground and not groubd.

Section 2.4.2: why did you use acidified detergent to wash the plants ?

“The samples were then pulverized in a wiring blender, which was cleaned with a hairbrush after each sample, and digested in di-acid (9:4 v/v) of nitric acid (HNO3)/perchloric acid (HClO4). The nutrient (N, P, K, S and Zn) concentration in plant samples were determined by the methods (Table 1) as described by Subbiah and Asija [18]. For N content, grain and straw samples were digested in concentrated H2SO4-salicylic acid mixture and digestion mixture 199 (potassium sulphate 400 parts, copper sulphate 20 parts, mercuric oxide 3 parts, selenium 200 powder 1 part). Filtered sample used for zinc estimation with the help of atomic absorption spectrophotometer. Sulphur in whole plant parts and seeds was estimated by Turbidimetric Method by using spectrophotometer at 490 λnm and expressed the concentration 203 in percentage “ Please add some information; for instance you stated the digestion method for the N content but not the analyzing method.

“Five soil sub-samples (0-15 cm) from each plot were collected before the growing of rice during kharif 2013 (initial soil sample) and after the harvest of crop in rabi season of 2015 (post-harvest) using stainless steel tube augers. Initial soil samples were taken from 15cm top soil. After uniform mixing of sub-samples, representative soil samples were air dried and ground to pass through a 2-mm stainless steel sieve for determination of different soil parameters by standard methods. The plant samples collected after harvesting the crop were dried, grounded and kept in polythene packets with labels for chemical analysis.” In this paragraph, at first you talk about soil samples, but then you say about plant samples (and later on again soil) ! I think there is a mistake and that it should be soil instead of plant.

Table 4, 5, 6, 7, 8, 9, 10, 11, 12 and 13: there is no statistical information; please add them so it is easier and faster to analyze the data of the table.

Figures 1, 2 and 3: same remarks. Here it seems that replications were made, but it is not clear in the Materials and Methods section and it is not visible at all in the tables !!

Discuss more your results, and compare it to other studies.

Author Response

Response to Reviewer_3 comments

The paper is an interesting research on the effect of fertilizer applications on plant growth. It is well written and fit the journal scoop. However, based on the description of the experimental design and the presentation of the data, it seems that no replicate was made for each treatments. For me, this is the most negative aspects of the research! How can it be possible to draw conclusion based only on 1 observation?! The second negative aspect of this study is the lack of discussion of the results.

 Figure 1: I think the point for the relative humidity are misplaced, they are below the 0 line. Add the units on the axe labels. Write the °C properly.

Authors’ response: Thanks for your advice. Necessary corrections have been made.

Table 1: please give a brief description of the methods used.

Authors’ response: Thanks for your advice. The methods mentioned in Table one is very common and generally adopted for soil testing. If the methods are described, the length of the paper will be increased.

Table 1: Soil testing methodology

Particulars	Method followed
pH	Determined with the help of pH meter in 1:2.5 ratio of soil water suspension) [17]
Available nitrogen (kg ha-1)	Alkaline permanganate method [18]
Available phosphorous (kg ha-1)	Brays method No.1 [19]
Available potassium (kg ha-1)	Flame photometer method [20]
Zinc (mg kg-1)	DTPA extractable Zn estimation by AAS [21]
Sulphur (kg ha-1)	Turbidimetric method [22]

Materials and Methods, section 2.2: you state that in T1, ample dose of N, P, K, S and Zn were applied; but you do not specify if it is a regular dose or an ample dose of the diverse elements in the other treatments. Please specify.

Authors’ response: Thanks a lot for your comments. The ample dose mentioned in the treatment (T₁) is the recommended balanced fertilizer dose for different seasons (150:60:70 kg ha^-1 of N: P₂O₅: K₂O and 200:80:90 kg ha^-1 of N: P₂O₅: K₂O in kharif and boro seasons).

Section 2.4.1: you sampled the plant in different rows for diverse analyses… how can be sure that there was no row effect due to the heterogeneity of the soil? Why did you not sampled the plants randomly in the all plot?

Authors’ response: Thanks for pointing out the mistakes. We have now corrected.

In the LAI formula, I think there is a spelling mistake, it should be ground and not groubd.

Authors’ response: Extremely sorry. We have now corrected.

Section 2.4.2: why did you use acidified detergent to wash the plants?

“The samples were then pulverized in a wiring blender, which was cleaned with a hairbrush after each sample, and digested in di-acid (9:4 v/v) of nitric acid (HNO3)/perchloric acid (HClO4). The nutrient (N, P, K, S and Zn) concentration in plant samples were determined by the methods (Table 1) as described by Subbiah and Asija [18]. For N content, grain and straw samples were digested in concentrated H2SO4-salicylic acid mixture and digestion mixture 199 (potassium sulphate 400 parts, copper sulphate 20 parts, mercuric oxide 3 parts, selenium 200 powder 1 part). Filtered sample used for zinc estimation with the help of atomic absorption spectrophotometer. Sulphur in whole plant parts and seeds was estimated by Turbidimetric Method by using spectrophotometer at 490 λnm and expressed the concentration 203 in percentage.”

Please add some information; for instance, you stated the digestion method for the N content but not the analyzing method.

Authors’ response: Thanks for your valuable remarks. Necessary corrections have been made.

“Five soil sub-samples (0-15 cm) from each plot were collected before the growing of rice during kharif 2013 (initial soil sample) and after the harvest of crop in rabi season of 2015 (post-harvest) using stainless steel tube augers. Initial soil samples were taken from 15cm top soil. After uniform mixing of sub-samples, representative soil samples were air dried and ground to pass through a 2-mm stainless steel sieve for determination of different soil parameters by standard methods. The plant samples collected after harvesting the crop were dried, grounded and kept in polythene packets with labels for chemical analysis.”

In this paragraph, at first you talk about soil samples, but then you say about plant samples (and later on again soil)! I think there is a mistake and that it should be soil instead of plant.

Authors’ response: Necessary corrections have been made.

Table 4, 5, 6, 7, 8, 9, 10, 11, 12 and 13: there is no statistical information; please add them so it is easier and faster to analyze the data of the table.

Authors’ response: In this regard we would like to mention that statistical analysis has been done and under the subheading 2.5 the statistical procedure adopted has been discussed. Further, standard error of means (SEm±) and critical difference at 5% probability level of significance (CD, P= 0.05) are given to compare treatments.

2.5 Calculations and statistical analysis

The experimental data were analyzed statistically by using analysis of variance (ANOVA). The standard error of means (SEm±) and critical difference at 5% probability level of significance (CD, P= 0.05) [26]. The Excel software (Microsoft office Home and Student version 2019-en-us, Microsoft Inc., USA) was used for statistical analysis, drawing of graphs and figures.

Figures 1, 2 and 3: same remarks. Here it seems that replications were made, but it is not clear in the Materials and Methods section and it is not visible at all in the tables!!

Authors’ response: Necessary corrections have been made. The experiment was replicated thrice.

Discuss more your results, and compare it to other studies.

Authors’ response: Added as per your suggestion.

Author Response File: Author Response.docx

Reviewer 4 Report

The paper is good and the experimental work done seems to support the results. I have two remarks: one is the abundance of data and the length of the paper which is more of a thesis than an article. The other is the title of the paper which suggests site specific application - which is true - however does not deal with the agronomic application of that field. I suggest the authors concerning the first remark to shorten the paper by selecting not necessary data. The other is to change the title.

 

Author Response

Response to Reviewer_4 comments

 

Comments and Suggestions for Authors

The paper is good and the experimental work done seems to support the results.

Authors’ response: Thank you very much for your valuable comments.

I have two remarks: one is the abundance of data and the length of the paper which is more of a thesis than an article. The other is the title of the paper which suggests site specific application - which is true - however does not deal with the agronomic application of that field. I suggest the authors concerning the first remark to shorten the paper by selecting not necessary data. The other is to change the title.

Authors’ response:

1. Actually, the materials and method part has been described in detail as the can get related information on the multi-locational field trial carried out for two seasons. Further, chemical analysis of post-harvest soil also carried out to find nutrient use efficiency and the procedure was described. These might increase the length.

 

2. Thank you for your valuable suggestion. The experiment was conducted in multiple locations to find out the location and cropping systems specific nutrients recommendation. So, the title may be as ‘The Productivity and Nutrient Use Efficiency of Rice–Rice–Black Gram Cropping Sequence are Influenced by Location Specific Nutrient Management’

 

 

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The manuscript was corrected according almost all my comments but minor corrections are still required:

1) Line 265: Please define what does it mean "crtitical difference". Is was based on multiple comparison procedure like e.g. LSD or Tukey's method? It should be clearly stated.

2) What is presented in Figures 2, 3 and 4 as an error bars? It is SEm or CD or something else? It should be clearly stated.

 

Author Response

Response to Reviewer_2 comments

 

Comments and Suggestions for Authors

The manuscript was corrected according almost all my comments but minor corrections are still required:

1) Line 265: Please define what does it mean "critical difference". Is was based on multiple comparison procedure like e.g. LSD or Tukey's method? It should be clearly stated.

Authors’ response: Thanks for your remarks and query about critical difference (CD). The critical difference (CD), the smallest difference between sequential experimental results which is associated with a true change in the treatment, is commonly calculated by assuming the same standard deviation (SD) for the initial and subsequent measurements.

2) What is presented in Figures 2, 3 and 4 as an error bars? It is SEm or CD or something else? It should be clearly stated.

Authors’ response: It is standard error of mean (SEm±) bars in Figures 2, 3 and 4. Standard error mean (SEm±) bar was calculated from three replicates for each treatment. We have now discussed details in the caption of all figures.

 

 

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors made corrections that improved the manuscript.

I would accept this paper after 2 minor revisions are made.

1/ Regarding the fertilizer dose: the authors gave the doses in T1 but we don't know if it is the same amounts (without certain elements) in the other ones, please specify it.

2/ section 2.4.2: the authors did not answer and explain why they washed plants with acidified detergent.

Author Response

Response to Reviewer_3 (second round) comments

Comments and Suggestions for Authors

The authors made corrections that improved the manuscript.

I would accept this paper after 2 minor revisions are made.

1/ Regarding the fertilizer dose: the authors gave the doses in T1 but we don't know if it is the same amounts (without certain elements) in the other ones, please specify it.

Authors’ response: Thanks for the informative suggestion. You are absolutely right. We have been now specified details for better understanding as [after line 153]:

In case of T₂: P, K, S and Zn were applied with ample dose and N omitted, in T₃: N, K, S and Zn were applied with ample dose, P omitted and the same manner was applied for remaining treatments up to T₆. But, in T₇ (local variety ‘Kabirajsal’ in kharif and HYV ‘IR 36’ in boro were taken) as unfertilized control (without any fertilizer) and in T₉ (where HYV and hybrid were considered as ‘MTU 7029’ and ‘Arize Tej’ during kharif and boro seasons, respectively) with ample dose of fertilizer as applied in T1. However, in T₈, local variety ‘Kabirajsal’ in kharif and HYV ‘IR 36’ in boro were considered with ample dose of fertilizer as per the recommendations (T₁) respectively).

2/ section 2.4.2: the authors did not answer and explain why they washed plants with acidified detergent.

Authors’ response: We would like to mention that the plant sample for nutrient estimation were not washed in acids. Authors followed the standard procedure as described by Subbiah and Asija [Ref. 18] and it was acid digestion to measure the nutrients content in the plant samples.

Following part is for your kind reference [lines 197-204].

The samples were then pulverized in a wiring blender, which was cleaned with a hairbrush after each sample, and digested in di-acid (9:4 v/v) of nitric acid (HNO₃)/perchloric acid (HClO₄). The nutrient (N, P, K, S and Zn) concentration in plant samples were determined by the methods (Table 1) as described by Subbiah and Asija [18]. For N content, grain and straw samples were digested in concentrated H₂SO₄-salicylic acid mixture and digestion mixture (potassium sulphate 400 parts, copper sulphate 20 parts, mercuric oxide 3 parts, selenium powder 1 part) and measured by following micro-Kjeldahl method [18].

 

Author Response File: Author Response.pdf