Characteristics and Impacts of Water–Thermal Variation on Grain Yield in the Henan Province, China, on Multiple Time Scales
Round 1
Reviewer 1 Report
Characteristics of Water-Heat Variation under Multiple Time 2 Scales and Their Impacts on Grain Yield in Henan Province of 3 China
Specific comments are discussed as below:
Abstract:
L 12-13 Water and heat resources have always played a vital role in the main grain production, and they have changed significantly due to climate change.
Avoid general statements and please highlights the results.
L 27 Under the seasonal scale, the intensity of extreme precipitation events increased in summer; (3) our 27 study suggested that the fluctuations in grain yield were caused by climate change.
What is climate change, explain what caused extreme precipitation, discuss from your results.
L 57 Presently, many researchers have investigated, change the ward researcher…you can cay many studied by …
L73 region [20,21]. Can be replace as region [20-21].
L123-125 Henan Province ranges from 31°23′ to 36°22′ N by latitude, 110°21′ to 116°39′ E by longitude, borders the east by Anhui Province and Shandong Province, the north by Hebei Province and Shanxi Province, the west by Shaanxi Province, and the south by Hubei Province, with a total area of 16,700 km2…rephrase this setntence.
L138 Zhengzhou city (site 57083, 113.65 E, 34.72 N, altitude 110.4 m)- please modify and keep degree in the before E and N.
L 165 Extreme temperature and extreme precipitation…looks the sentence is not complete.
The equations 1-22 has well written, but the front is same. Please make it identical…check properly
L 246 were 215.70 °C/10 a and 221.75 °C/10 a, … what is a
L 328 The precipitation had 3 variation cycles throughout the period at the annual scale, which were about 23–28 years, 15–20 years, and 7–10 years, respectively (Fig. 5)…modify the sentence.
L 350-353 The variation trend of the maximum value of daily maximum temperature was the largest in spring, followed by summer and autumn, and the smallest in winter under seasonal scale, with the variation rates 0.7 °C/10a, 0.3 °C/10a, 0.2 °C/10a, and 0 °C/10a, respectively. ..Modify the sentences
Many places I observe in results section -1.2 mm/10 a, -1.9 mm/10 a, 16.9 mm/10 a, and 1.5 mm/10 a…what is “a” ..please explain? Its looks bad sentence
The evaluation of micro furrow irrigation performance with different treatments….what is furrow its channel?
L409-417 Climate yield was influenced by the indicators equally. Under the seasonal scale, summer grain yield in Henan Province was most influenced by the daily temperature range (correlation degree of 0.976), second influenced by ≥0 °C accumulated temperature, ≥10 °C accumulated temperature and precipitation (correlation degree of 0.901–0.924), and least influenced by extreme precipitation (correlation degree of 0.588); autumn grain yield was most 414 influenced by ≥0 °C accumulated temperature, ≥10 °C accumulated temperature and daily temperature range (correlation degree of 0.946–0.964), second influenced by precipitation (correlation degree of 0.926), and least influenced by extreme precipitation (correlation degree of 0.901).
Very big sentence I ever seen. Please make it compress and meaning full. What is Climate yield?
Modify yield [52,53] ..as yield [52-53].
How author calculated min and max temperature…The sentence in conclusion
the increase in the minimum value of the daily minimum temperature was about 2–3 times greater than that of the maximum value of the daily maximum temperature…why it happens any scientific suggestions.
Author analyzed temperature and precipitation in grain yield why you wrote Climate change caused fluctuations?
Please modify the conclusion section based on your research findings.
Overall comments the manuscripts need through revision. However, the citations are not in proper format. Make it as per MDPI format.
Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
The article may be useful for practical use in agricultural production in China. This work is due to global climate change in recent years: rising temperatures, alternating floods and droughts. It should be noted that a lot of research has already been devoted to this topic and the presented article is not unique. Thus, in the Discussion section, the authors refer to previously obtained similar results: “Tao et al. [46] and Xiao et al. [47]". The conclusions on the article on the effect of temperature and humidity on the yield do not introduce significant new data. The patterns presented in the article characterize only a local part of the planet in one province of China and cannot be extrapolated to the entire world agriculture. The article is more devoted to the study of long-term meteorological and climatic changes, and not to agriculture. Yields are only described from section 3.4. In sections 4.2 and 4.3, most of the conclusions are well known and do not provide new information. The list of references contains an excessive number of references to works from one country, which reduces the level of comparative analysis of the research results. In general, according to the reviewer, the article is of no significant interest to readers.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
This manuscript about changes and variations in climate variables and grain yields since 1978 in Henan Province of China, contains a number of interesting elements. However, it also contains many imprecise and unclear statements, which make it difficult to judge its potential. Some ambiguities are due to English language issues; others seem to be related to insufficient analysis and/or interpretation of results from the analysis. As a result, some of the conclusions don't seem to be adequately underpinned.
The discussion section also lacks an analysis of strengths and weaknesses of the approach followed. For example, the weather/climate variables selected to assess the occurrence of climate change, and their correlation with grain yields, are, despite the significant correlations found, by themselves insufficient to explain changes in yield, and inadequate to predict future changes or risks to crop yields. This would require a more in depth analysis using more refined tools such a biophysical simulation models, combined with analysis of trends in agro-technological development.
The specific comments below are meant as examples to illustrate the above.
I’ve never seen the term “heat resources” (line 12, and many other places throughout the text) used in the sense as it is used in this manuscript. Browsing on the internet, I find it used to indicate (i) information material about heat and about how to mitigate the negative impacts of excessive heat; and (ii) devices or processes that generate heat. To avoid confusion, I would suggest to use the word temperature in this paper. Depending on the sentence, water resources could remain or be replaced with water availability, rainfall or precipitation. For example, the phrase “water and heat resources are the two most important climate elements in agriculture” could become “rainfall and temperature are the two most important climate elements in agriculture”.
From the abstract, it is not clear what is meant with different time scales or multiple time scales.
Lines 21-23 need to be reformulated. It states that there was an increasing trend for precipitation at annual and seasonal scales, but a decreasing trend in spring.
Line 27-28, Imprecise formulation: “our study suggested that the fluctuations in grain yield were caused by climate change”,
Line 29: “…effect on a time scale” of what?
Lines 40-42, seems to suggest a global temperature increase of at least 2.59 oC since 1850 (i.e. 1 + 1.09 + 1.5), according to the 6th IPCC Assessment Report. This is incorrect.
In my understanding, the term evolution (as used in lines 54, 57 and several other places) is not appropriate to indicate climate change.
Line 84: I can only imagine the meaning of “wave-increasing trend”.
Line 85, what is climate yield?
According to line 101: “The above studies provide a specific theoretical basis..”. However, all studies mentioned are empirical, showing correlations between yields and climate (and other) aspects, with little or no theoretical explanation.
Section 2.3.4 (starting at line 203) I am not familiar with the HP filtering method, but in my perception it is not suitable to distinguish crop yield trend due to climate change from yield trend due to technological development in time series. NB that technological development can also adapt to climate change.
Section 2.3.5 The use of the Gray correlation analyses and its pros and cons are not clear.
Table 1 (starting line 254) is not self-explanatory. The second and third columns have the same header (what is the difference?). The unit in the second and third columns is °C; shouldn't this be °Cd (i.e. degree days)?
In figure 2, it would be nice to also see the actual cumulative temperatures per season per year.
The paragraph starting at Line 288, about cycles of water and heat elements, states that “.. accumulated temperature in Henan Province will experience a variation process from more to less in about 28 a…”. I don’t think such a statement about the future can be made on the basis of a time series of only 43 years (1978-2021).
Table 3 (starting line 376): The header doesn’t seem to make sense. It is totally disconnected from the rest of the paper.
In Figure 7, the term “Climate yield” is misleading. In the manuscript, it represents the difference between actual grain yield and the long-term (1978-2021) trend, which is attributed to technological development. However, part of the long-term trend might also be due to climate change and part of the residual variation might be due to variations in agronomic management that are not related to weather conditions.
It must be noted that the correlation analysis (starting line 403) performed can only indicate correlations between yield and interannual weather variations; but not a possible relation between changes in yield and (gradual) climate change. Throughout this section, and also in the 4th conclusion (line 511), I would change “influenced by” to “correlated with”.
The authors often confound climate change with (annual) variations in weather patterns; for example, in line 467, where they state that “In this study, we found that climate changes caused fluctuating changes in the grain yield of Henan Province…”. This also affects the third conclusion. In my view, on the basis of the results in this study, the cause of the different trends for yields of autumn grain (winter wheat?) and summer grain (maize?) remains unclear. It would have been interesting to address this point.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors have made major corrections to the article. In its present form, the article has been significantly improved and can be recommended for publication.
