The Effect of Cropping Method and Botanical Form on Seed Yielding and Chemical Composition of Chickpeas (Cicer arietinum L.) Grown under Organic System

Round 1

Reviewer 1 Report

 I have made my comments and suggestions on the "pdf file" submitted by authors to Agronomy Journal.

As a general comment, I suggest to discuss the results of this study with the referenced works along the section Results and Discussion. In addition, in some instances the messages are contradictory.

Finally, the ms needs a careful revision of English related with comparative sentences or repeated phrases. 

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 1 Comments

Authors proved All suggestion and comments enclosed on the "pdf file" and marked in yellow colour by reviewer 1.

Reviewer 2 Report

This article presents data from a really interesting and useful trial comparing 2 varieties of chickpea grown as an intercrop with barley or oats. The findings will be useful to those interested in uptake of agroecological practices in arable farming and potential benefits of legumes in arable cropping systems. 

I have a few comments and suggestions that I hope might help improve the manuscript for publication.

1. the text needs to be thoroughly checked for English grammar, e.g. line 21, 24, 63, 119, 122 and so on.
2. Line 66/67 mentions some potential multiple benefits of legumes in cropping systems. This is really interesting and could be expanded on, particularly in the light of the need for more agroecological practices in farming for environmental benefits, not just yield. Similarly, the paper would benefit from a final statement (and more discussion earlier on) regarding the potential value of intercropping with legumes compared to growing in monoculture. From this work, do the authors believe that there is a benefit of this cropping system? And what are those potential benefits? Would they recommend that growers use intercropping as a way to achieve multiple benefits? What are the advantages over and above growing the crops separately, both in terms of soil, environment etc, but also for product quality and yield risk
3. Section 2.1. – methods – what was the row spacing of the intercrop? And does row intercrop mean alternate rows of the two crops rather than a complete mix?
4. Section 2.2 heading – should read: chemical analysis of chickpea seeds, not lentil?
5. Section 2.3. – statistical analysis could do with little more description – what were the variables and factors, was this done as an Analysis of Variance? What statistical package was used?
6. The various reported figures for average yields in the introduction and discussion are wildly variable – 0.8 t/ha in the introduction as a global average, compared to 2 t/ha or more from studies quoted in the discussion. What is the typical range and, in the discussion, where did the studies take place that quoted much higher values? What is it about them that makes them so much better yielding than the global average? 
7. Presentation of results. Most of the rest of my comments relate to improving the clarity of the findings as there appear to be a few contradictions in the way it is currently presented: Table 1 – does it make sense to have thousand grain weight for cereal and pea combined when they are so different in size? Would it not make more sense to show this separately for the cereal and pea.
   In the abstract, it says that oat was more competitive than barley with pea, but from the table 1 it looks as though chickpea did better in a mix with oat than with barley, so wouldn’t this be the other way around? It’s a bit difficult to interpret the yield data without separating out the grain from the pea yields – could these not be shown separately in graphical form? E.g. a bar chart (with standard errors) showing yield of pea when intercropped with oat, yield of pea when intercropped with barley, yield of barley when intercropped with pea and yield of oat when intercropped with pea, all in relation to the yields of each of the respective monocrops which could be indicated on the figure as a line across at the level of yields for each of pea, barley and oat on their own. That would make it easy to see the variation and allow an immediate visualisation of the extent of overyielding versus yield loss for each combination.
   And again line 177 - % share of pea was lower in combination with oat than with barley, but the chick pea yields were higher (for K) and no different (for d). I think we’d need to see the total yields for all components plotted together to get a clearer picture of these interactions. I’m not sure why the yield data for K is better with oats than barley when the % share, number of pods, seeds per plant, seed weight per plant are all lower? Could this be explained?
   Line 169-171 – the first sentence says that pea grown as a monocrop yielded better, then the next sentence says the opposite – clarify
   

   Similarly, in the conclusions – “Higher yield was noted in chickpea grown with supporting crops than in sole cropping. Significantly higher chickpea seeds yield was noted in sole cropping than with cereals.” To me that’s contradictory. In table 1, overall yields (pea plus grain) were higher in intercrop, but chickpea yields (as a component) were lower in intercrop than the monocrop. This needs to be clarified.

   Line 257 – again, oat quoted as being more competitive with lower % legume seed in oat than barley, but seed yield for k was higher or no different in oat than in barley. Why would that be?

8. In the discussion, differences in protein and phosphorous between varieties and with weather conditions are discussed, but the effect of cropping system is really interesting and I think is underplayed! This is a really nice result that could be brought out – that even though yields might be lower in an intercrop, the quality of the product is better with higher protein and P content but no difference in fat? Or have I misinterpreted this? Similarly, the last para of conclusions mentions quality differences between varieties, but the effect of intercropping on quality is really interesting and should be emphasised.

9. Finally, I wonder whether the results/discussion section could be rearranged for clarity and to draw out the key messages better? There is much reference to other studies of chickpea yields in relation to fertilisation or sowing season, or just quoted yields, but these seem less relevant to this study which is focusing on organic cropping system. Are there other/more intercropping studies that could be compared to the results reported here? The effect of intercropping relative to monocrop seem very variable – maybe this and the reasons for this could be drawn out and an overall assessment made of whether overyielding is possible or likely for chickpea in combination with a cereal? Perhaps if the results could be reported first (with graphical representations of the yield/quality results), and then the discussion section separated out from the results and divided into sub-sections e.g.
   • Variety differences (what characteristics make one type more suited to intercropping than another, what are the differences in performance and quality compared to other studies)
   • Impact of weather and climate on performance
   • Effect of fertilisation. This study is organic - so what is the reduction in yield of chickpea without fertiliser and what is the potential benefit of the legume to the cereal when grown in a mix in an organic system? 
   • Finally, and importantly, how does the performance of the intercrop presented here relate to other studies and what are the potential benefits to agricultural production by using this cropping system? 

Author Response

Response to Reviewer 2 Comments

Point 1: The text needs to be thoroughly checked for English grammar, e.g. line 21, 24, 63, 119, 122 and so on.

Response 1: Please provide your response for Point 1. (in red) The text have been proved in the manuscript file.

Point 2. Line 66/67 mentions some potential multiple benefits of legumes in cropping systems. This is really interesting and could be expanded on, particularly in the light of the need for more agroecological practices in farming for environmental benefits, not just yield. Similarly, the paper would benefit from a final statement (and more discussion earlier on) regarding the potential value of intercropping with legumes compared to growing in monoculture. From this work, do the authors believe that there is a benefit of this cropping system? And what are those potential benefits? Would they recommend that growers use intercropping as a way to achieve multiple benefits? What are the advantages over and above growing the crops separately, both in terms of soil, environment etc, but also for product quality and yield risk

Response 2: The text have been add in the manuscript file. Legume is characterized by high susceptibility to lodging, which adversely influenced seed yield and impedes harvesting with a harvester. Intercropping with supporting plants can effectively reduce lodging of crops susceptible to it. Authors believe that there is a benefit of cropping method with supporting crops. A condition for using this cropping method is to select a species of supporting crop and its percentage in the mixture that will help reduce crop lodging.

Point 3. Section 2.1. – methods – what was the row spacing of the intercrop? And does row intercrop mean alternate rows of the two crops rather than a complete mix?

Response 3:  Row spacing is 20 cm. It is mean alternate rows of the two crops

Point 4. Section 2.2 heading – should read: chemical analysis of chickpea seeds, not lentil?

Response 4: It has been proved in the text of manuscript. Of course it is chemical analysis of chickpea seeds not lentil.

Point 5. Section 2.3. – statistical analysis could do with little more description – what were the variables and factors, was this done as an Analysis of Variance? What statistical package was used?

Response 5: Authors add and complete in the Section Material and methods (section 2), subsection (2.3.) the date connect to statistical analysis. The results were statistical analysis of variance using Statistica v.10.0 program.

Point 6. The various reported figures for average yields in the introduction and discussion are wildly variable – 0.8 t/ha in the introduction as a global average, compared to 2 t/ha or more from studies quoted in the discussion. What is the typical range and, in the discussion, where did the studies take place that quoted much higher values? What is it about them that makes them so much better yielding than the global average? 

Response 6: It is proved in the text. In was mistake

Point 7. Presentation of results. Most of the rest of my comments relate to improving the clarity of the findings as there appear to be a few contradictions in the way it is currently presented: Table 1 – does it make sense to have thousand grain weight for cereal and pea combined when they are so different in size? Would it not make more sense to show this separately for the cereal and pea.
In the abstract, it says that oat was more competitive than barley with pea, but from the table 1 it looks as though chickpea did better in a mix with oat than with barley, so wouldn’t this be the other way around? It’s a bit difficult to interpret the yield data without separating out the grain from the pea yields – could these not be shown separately in graphical form? E.g. a bar chart (with standard errors) showing yield of pea when intercropped with oat, yield of pea when intercropped with barley, yield of barley when intercropped with pea and yield of oat when intercropped with pea, all in relation to the yields of each of the respective monocrops which could be indicated on the figure as a line across at the level of yields for each of pea, barley and oat on their own. That would make it easy to see the variation and allow an immediate visualisation of the extent of overyielding versus yield loss for each combination.
And again line 177 - % share of pea was lower in combination with oat than with barley, but the chick pea yields were higher (for K) and no different (for d). I think we’d need to see the total yields for all components plotted together to get a clearer picture of these interactions. I’m not sure why the yield data for K is better with oats than barley when the % share, number of pods, seeds per plant, seed weight per plant are all lower? Could this be explained?
Line 169-171 – the first sentence says that pea grown as a monocrop yielded better, then the next sentence says the opposite – clarify

Similarly, in the conclusions – “Higher yield was noted in chickpea grown with supporting crops than in sole cropping. Significantly higher chickpea seeds yield was noted in sole cropping than with cereals.” To me that’s contradictory. In table 1, overall yields (pea plus grain) were higher in intercrop, but chickpea yields (as a component) were lower in intercrop than the monocrop. This needs to be clarified.

Line 257 – again, oat quoted as being more competitive with lower % legume seed in oat than barley, but seed yield for k was higher or no different in oat than in barley. Why would that be?

Response 7: In the Table 1 the data showed thousand grain weight for cereal and pea in spite of that the the size are different because it is quite important characteristic. While for cereal separately have been showed in the Table 9 titled: Number, weight of cereals grain per plant (g) and thousand grain weight (g) of cereals depending on method sowing depending on type (k – kabuli; d – desi; ns – not significant at P ≤ 0.05).

We think that data showed in the tables are more clear than in the graphical figures.

The recorded difference in the yield of chickpea in the form of kabuli cultivated and oats compared to the yield with barley is small, the differences in the structure of plants are also very small, and the observed difference in yield is difficult to explain, if we presented the crop rounded to one place after the chisel there would be same differences.

Sentence in the line 169-171 – has been corrected.

In the conclusions sentence– “Higher yield was noted in chickpea grown with supporting crops than in sole cropping. Significantly higher chickpea seeds yield was noted in sole cropping than with cereals.” Has been proved.

Point 8. In the discussion, differences in protein and phosphorous between varieties and with weather conditions are discussed, but the effect of cropping system is really interesting and I think is underplayed! This is a really nice result that could be brought out – that even though yields might be lower in an intercrop, the quality of the product is better with higher protein and P content but no difference in fat? Or have I misinterpreted this? Similarly, the last para of conclusions mentions quality differences between varieties, but the effect of intercropping on quality is really interesting and should be emphasised.

Response 8: Plants of both cereal species are much higher than chickpea plants, which had an adverse effect on protein accumulation in seeds of this species regardless of the cereal species, while the differences in the content of other chemical components in chickpea seeds were relatively small, despite the fact that there were statistically significant or insignificant differences (potassium).

Point 9. Finally, I wonder whether the results/discussion section could be rearranged for clarity and to draw out the key messages better? There is much reference to other studies of chickpea yields in relation to fertilisation or sowing season, or just quoted yields, but these seem less relevant to this study which is focusing on organic cropping system. Are there other/more intercropping studies that could be compared to the results reported here? The effect of intercropping relative to monocrop seem very variable – maybe this and the reasons for this could be drawn out and an overall assessment made of whether overyielding is possible or likely for chickpea in combination with a cereal? Perhaps if the results could be reported first (with graphical representations of the yield/quality results), and then the discussion section separated out from the results and divided into sub-sections e.g.

Variety differences (what characteristics make one type more suited to intercropping than another, what are the differences in performance and quality compared to other studies)

Impact of weather and climate on performance

Effect of fertilisation. This study is organic - so what is the reduction in yield of chickpea without fertiliser and what is the potential benefit of the legume to the cereal when grown in a mix in an organic system? 

Finally, and importantly, how does the performance of the intercrop presented here relate to other studies and what are the potential benefits to agricultural production by using this cropping system? 

Response 9. Chickpea plants of desi form are higher than the form of kabuli, which favorably affects the number of grains in both cereal species, thousand seeds weight and the number of grains and the number of shoots in barley. Which indicates that desi has a better effect on cereals grown with it than the form of kabuli.