关键词: 气候变化, 冬小麦, 灌浆期, 干热风, 商丘

Abstract:

Climate change is producing significant impacts on global agricultural production. Climatic variations affect crop production, and tend to be a key constraint of agricultural production, primarily on continuous increase of winter wheat yields worldwide. The great uncertainties in predicting the effects of climate change on wheat production are most likely due to less understanding of the responses of wheat production to extreme climatic factors, e.g. high temperatures, low humidity as well as high wind speed. Dry-hot wind hazard represents one of the main natural disasters for Chinese winter wheat production, especially in the Huang-Huai-Hai Plain. However, there still exist great uncertainties of the effects of dry-hot wind hazard on winter wheat production, mainly due to the gaps of long-term observations. Therefore, we selected Shangqiu as the case study area to determine the occurrence regularity of dry-hot wind hazard on winter wheat production in the Huang-Huai-Hai Plain. We analyzed regional meteorological data with daily resolution in the later growth stage of winter wheat during the period 1963-2012. In accordance with the meteorological industry standards of "Disaster Grade of Dry-hot Wind for Wheat" by the China Meteorological Administration, we synthetically analyzed the distribution of annual average days of dry-hot wind in winter wheat growing seasons and the associated responses to the climate change. Hence, the relationship between dry-hot wind times and winter wheat yields was examined. The results showed that the annual average days of light and severe dry-hot wind tended to decline in recent 50 years. Great inter-annual variations of light and severe dry-hot wind were observed. The significant inter-annual variations were related with the corresponding meteorological conditions of temperature, moisture and wind speed. The most serious damages of both light and severe dry-hot wind occurred in the 1960s, while less damages appeared in the 1980s and the last decade, which could be also explained by the corresponding temperature, moisture and wind speed conditions. From 1963 to 2012, a climatic mutation point of daily maximum temperature was found in 1972 (p>0.05). The wind speed at 14:00 and the relative humidity at 14:00 were closely related to the hazard. A climatic mutation point of the wind speed at 14:00 was found around 1984, and climatic mutation of the relative humidity at 14:00 was found in 1981 (p<0.05). Daily maximum temperature and wind speed at 14:00 and the relative humidity at 14:00 played a major role in the decreasing trend of dry-hot wind disaster, and the significant decrease of wind speed at 14:00 was a main factor in Shangqiu. Dry-hot wind hazard had a strong response to climate change. Yields of winter wheat were negatively correlated with annual average days of dry-hot wind in Shangqiu (p<0.05). In actual practices, great attention should be paid to the defense of dry-hot wind for winter wheat production. Thus, the most effective measures have to be taken to enhance the resistance of winter wheat to dry-hot wind hazard through improving field microclimate condition.

Key words: climate change, winter wheat, grain filling stage, dry-hot wind, Shangqiu