Actual impacts of global warming on winter wheat yield in Eastern Himalayas

Himalayas, are among the areas most vulnerable to global warming, however, little is knownabout warming impacts on the crops. Therefore, the actual affects of anticipated warming onwinter wheat were tested in Tibet, China. During the period 1988-2012, Tibet region hasexperienced a large increase in daily mean, minimum and maximum temperatures during wheatgrowing seasons by 0.50, 0.67 and 0.51 oC every ten years, respectively. The de-trended wheatyield increased by 34.4 kg ha-1 year-1 during this period. According to the historical data, 1 oCincrease in daily mean temperature could get 370.6 kg ha−1 gain in wheat yield. Similar gains inwheat yield were found in a field warming experiment with an increase of 1.1 oC in daily meantemperature. The field warming caused a significant reduction in the pre-anthesis phase andentire growth period by 14 and 13 days, respectively. The green leaf areas and spike number inthe warmed plots were significantly higher than that in non-warmed plots, while the grainnumber per spike was significantly lower in the former than the later (P<0.05). The mainmechanism underlying the positive affects of this moderate warming on wheat yield is throughimproving plant development and growth during the pre-anthesis phase by mitigating the lowtemperature limitation. This study suggests that further efforts should be directed towards theimprovement on agriculture infrastructure to utilize the positive affects of climatic warming oncrop production.

کلیدواژه ها:

Climate Change ، Food security ، Free air temperature increase ، Tibetan Plateau ، Wheat cropping