太行山山前平原近50 年气候变暖特征及其对冬小麦-夏玉米作物系统的影响

Characteristics and effects of climate warming on winter wheat/summer maize cropping system in recent 50 years in the piedmont of Mount Taihang

  • 摘要: 气候变暖及其对作物系统的影响是农业应对全球变化领域的主要研究命题之一。本文以河北省石家庄为例, 通过对近50 年气温数据以及作物系统热量资源变化特征的分析, 探讨了太行山山前平原区气候变暖对冬小麦-夏玉米作物系统的影响。山前平原区近50 年来明显变暖, 增温速率为0.35 ℃·10a-1, 其中冬季增温幅度最大, 为0.51 ℃·10a-1。气候变暖对作物的影响主要体现在有效积温的增加。近20 年来, >10 ℃积温较基准时段增加明显, 农业热量资源条件改善, 相当于农作物有效生育期延长10~20 d。由于较大的增温幅度及季节不均衡性, 冬小麦-夏玉米作物系统受到显著影响: 1990 年以来, 冬小麦生长季积温较基准时段上升幅度超过10%, 冬前生长期积温增加易造成旺长, 影响其安全越冬能力, 需推迟冬小麦播种期以适应气候变暖导致的不利影响; 气候变暖改善了夏玉米生育期热量条件, 综合考虑其收获期因小麦晚播而相应推迟的影响,夏玉米生长季>10 ℃积温可超过2 900 ℃, 满足中晚熟玉米品种平播的热量条件。

     

    Abstract: Climate warming and its impact on cropping systems constitute a major aspect of agricultural development research in countering climate change. While the North China Plain (NCP) is one of the most important crop production bases of China, the piedmont regions of Mount Taihang are the most productive zones in the plain. Winter wheat and summer maize constitute the basic cropping system in NCP. In such a tight double-copping system, heat condition is the main factor that controls both sowing and harvesting dates of the crops. This paper established a case study on temperature and agricultural heat resources data for the last 50 years in Shijiazhuang, a typical area of the piedmont regions of Mount Taihang, to discuss the characteristics of climate warming and the related impacts on winter wheat/summer maize cropping system in the piedmont regions of Mount Taihang. For the last 50 years, an obvious warming trend at 0.35 ℃·10a-1 was noted in the studied area. The trends in climate warming at the seasonal cycle were unequal, while a sharp increase (0.51 ℃·10a-1) in winter and a more moderate increase (0.20 ℃·10a-1) in summer. Climate warming in the studied area caused an increase in effective accumulated temperature (AT). In the last 2 decades, annual >10 ℃ AT increased obviously compared with the period of 1961~1990. The increased heat accumulation in recent years resulted in about 10~20 days extension of the suitable growing season. That favored crop growth and higher potential grain productivity. The sharp and unbalanced seasonal warming patterns resulting from regional climate warming distinctly impacted winter wheat/summer maize cropping system in the studied area. The emergence and seedling stages of winter wheat were temperature sensitive periods, and the suitable >0 ℃ AT was about 500~600 ℃ before overwintering stage. After 1990, the >0 ℃ AT in wheat season increased by 10% and the warmer seedling stage in turn decreased the safety level of overwintering stage. For that reason, wheat seeding date had been postponed to adapt to climate warming. Due to the higher heat resources and longer growing seasons, total >10 ℃ AT in maize season increased beyond 2 900 ℃. This was sufficient for mid-late maturity maize varieties in the piedmont regions of Mount Taihang.

     

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