Optimizing Sowing Date and Planting Density Can Mitigate the Impacts of Future Climate on Maize Yield: A Case Study in the Guanzhong Plain of China

Round 1

Reviewer 1 Report

• Quite interesting research. This manuscript gives important results since the optimization of sowing dates and planting densities could be effective counter measures to alleviate the negative impacts of future climate change on maize production not only in China but in many countries. It is an important study that could contribute to adaptation of maize in climate change scenarios.

Abstract.

I propose to authors to enrich the abstract with results/ conclusions, e.g.

1. “Therefore, based on the impacts of temperature rising on maize growth period and yield, cultivating longer maturing, and heat tolerant cultivar would become an important breeding direction for adapting to future climate change.
2. Water stress was still a key factor to limit yield increase under rain-fed conditions, although the optimal combination had a potential to optimize local climatic re­sources in maize growth period. It showed that drought stress would not only directly affect the growth and development of maize, but also restrain the effect of optimal measures. The yield increases degree for spring maize was more than summer maize under potential and rain-fed condition. This indicated that the optimal combinations were more effective for spring maize with longer growth period. Additionally, the efficiency of optimal combinations would weaken when climate change become more severe. Therefore, it is important to breed adapted variety for coping with future climate change, such as longer maturing and heat tolerant cultivar. The simulated results based on current cultivars pro­vide important reference significance for future agricultural production.
3. etc

In introduction and discussion it is necessary for authors to add a few international references to support their important findings.

Minor changed

• English language and grammar control it is necessary to be improved.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

The authors submitted an interesting study to validate the APSIM-Maize model with experimental data from a specific region in China with simulations of real and potential yield applying model inputs considering climate change scenarios for a given region. The model indicated adverse effects of climate change, but simulations also showed possible mitigation of the adverse effects by changes in date and/or seed density. The study is novel and original.

The study is very well introduced, providing sufficient theoretical background and appropriate formulations of the study's aims.

The methods are adequate, but some details should be added (comments below).

The results are presented clearly, and conclusions are well supported by the data. The discussion is appropriate.

1. In the introduction, please, provide a paragraph on possibilities, advantages, and trends using the APSIM model in climate change prediction studies on crop plants.
2. Please, in addition to climate conditions, write a short paragraph characterizing geographical and soil conditions, as well as the agronomic profile (cultivated crops, cultivation systems) in a given area, as the foreign readers are not familiar with the characteristics of this region. For this kind of studies, it can be relevant.
3. Please, ad into Material and Methods also the information on the technical realization and doses of irrigation. Maybe it is somewhere, but it should be clearly stated in methodics.
4. It is also needed to add the details on fertilizers used – nitrogen but all the fertilizers. That is required in agronomy papers

Author Response

Please see the attachment

Author Response File: Author Response.docx