摘要
摘要:水热条件是影响作物分布与农业生产的重要因素。玉米不仅是我国重要的粮食作物，同时也是重要的饲料作物和能源作物，探讨其生育期及各生育阶段水热条件的时空变化特征对农业应对气候变化带来的风险及粮食安全具有重要意义。本文选取平均温度（T_mean）、生长度日（GDD）、高温度日（KDD）、日照时数（SD）、有效降水（P_e）和灌溉需水量（IR）为水热条件指标，基于全国422个气象站点和292个农气站点观测数据，采用趋势和空间分析方法，揭示了1960—2018年中国九大玉米种植区玉米全生育期及各生育阶段水热条件的时空变化特征。结果表明，玉米生育期T_mean、GDD的增幅分别为0.18~0.36℃·（10a）^-1和5.73~41.23℃·（10a）^-1，东北、甘新区、黄淮海平原和黄土高原等种植区增加最显著。生育期KDD的高值区主要集中在黄淮海平原和甘新地区；除黄淮海平原西南局部区域呈不显著下降趋势外，其他地区呈增加趋势；且KDD的增加主要集中在苗期到花粒期。玉米生育期SD整体表现为显著下降趋势，其中黄淮海平原和黄土高原地区玉米各生育阶段均存在显著下降趋势，花粒期SD下降最明显。玉米生育期P_e和IR变化趋势总体上不显著但空间差异明显；除甘新区和内蒙P_e呈现不显著增加趋势外，全国大部分玉米种植区P_e呈不显著减少趋势。生育期IR在南疆及黄淮海平原西南部呈不显著减少、东北东南部不显著增加趋势；从各生育阶段来看，黄淮海平原区及东北地区P_e在穗期和花粒期减少且IR相对增加，黄淮海平原区及黄土高原西部的IR分别在播期和苗期呈现减少趋势。总体来看，全国玉米生育期热量资源有增加趋势，光照资源减少，有效降水和灌溉需水量的变化趋势不明显，但是各生育阶段及区域间水热条件变化差异明显，如黄淮海平原和黄土高原地区苗期到花粒期KDD增加显著但SD下降，高温胁迫可能会对玉米生长产生负影响，同时影响对水分的消耗。因此，未来研究更应该关注生育阶段的水热条件变化以及极端情况对玉米生长的影响。
关键词:气候变化/
玉米/
水热条件/
生长度日/
高温度日/
有效降水/
灌溉需水量
Abstract:Hydrothermal conditions affect crop distribution and agricultural development. Maize is an important food crop in China and is primarily used as a fodder and energy crop. However, the growth of maize is sensitive to climate change. Understanding the spatiotemporal characteristics of the hydrothermal conditions, especially during the growth period and at various growth stages of maize, is crucial for food security and for coping with the impacts of climate change. This study aims to explore the spatiotemporal characteristics of the hydrothermal conditions during the maize growth period and its various growth stages in different regions of China from 1960 to 2018. The mean temperature (T_mean), growth degree-day (GDD), killing degree-day (KDD), sunshine hours (SD), effective precipitation (P_e), and irrigation water requirement (IR) served as the hydrothermal condition indicators, incorporating the data from 422 meteorological stations and 292 agricultural stations. The spatial and temporal variations of each indicator were explored using trend and spatial analysis methods. The results showed that T_mean and GDD generally increased in the maize growth period, 0.18~0.36℃·(10a)^-1and 5.73~41.23℃·(10a)^-1, respectively, and T_mean and GDD had risen more rapidly in Northeast China, the Gansu-Xinjiang Region, and the Huang-Huai-Hai Plain. KDD increased in the summer maize planting areas, including the Huang-Huai-Hai Plain and Gansu-Xinjiang Region. KDD tended to increase nationally except in the southwestern part of the Huang-Huai-Hai Plain, where there was an insignificant decline. In the various growth stages, KDD mainly increased from the seedling stage to the flowering and kernel stages. SD in the maize growth period showed a significant downward trend, and there was a significant downward trend in each maize growth stage in the Huang-Huai-Hai Plain and the Loess Plateau. SD declined the most in the flowering and kernel stages. Changes in P_e and IR during the maize growth period were generally non-significant, but the changes varied in different regions. P_e in different growth stages generally decreased, except in the Gansu-Xinjiang Region and Inner Mongolia, where, in past years, the P_e values increased non-significantly. IR in the maize growth period tended to decrease in southern Xinjiang and the southwestern part of the Huang-Huai-Hai Plain, whereas IR increased non-significantly in parts of Northeast China. In the various growth stages, P_e decreased and IR increased at the heading and flowering stages in the Huang-Huai-Hai Plain and Northeast China, whereas IR tended to decrease during the sowing and seedling stages in the Huang-Huai-Hai Plain and the western part of the Loess Plateau. Overall, there was an increasing trend of heat resources during the maize growth period in the whole country. Solar radiation tended to decrease, with no significant changes in P_e and IR. However, there were significant differences in the water and heat conditions among growth stages and regions; KDD significantly increased from the seedling stage to flowering stage in the Huang-Huai-Hai Plain and Loess Plateau, whereas SD decreased in the same regions. Thus, high-temperature stress may negatively impact maize growth and affect water consumption in different maize growth stages. This study illustrated that changes in the hydrothermal conditions during different maize growth stages were more important than those experienced during the entire maize growth period. However, knowledge of the possible spatio-temporal changes in the hydrothermal conditions in different maize growth stages is still lacking; particularly, the climate extremes during different maize growth stages in different regions of China. The results of this study highlight the impact of climate change on crop production, although more detailed research is needed.
Key words:Climate change/
Maize/
Hydrothermal conditions/
Growth degree-day/
Killing degree-day/
Effective precipitation/
Irrigation water requirement



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