Abstract:

【Objective】 In order to study the responses and adaptation of winter-wheat yield and quality to climate warming at crop system scale in situ, a warming system with free air temperature increasing (FATI) techniques was designed and the warming effects at winter-wheat growing stages were investigated. 【Method】 In a field warming experiment, three warming scenarios (AW: all-day warming; DW: day warming; NW: night warming) were conducted during 2007-2009 in Nanjing, Jiangsu, China.【Result】 Two-year results showed that this FATI facility caused significant increments in field micro-environment temperatures. It formed 4 m2 of evenly and reliably warming area both at day time and night time, and the two-year average temperatures in the soil layer of 5 cm of the AW, DW and NW plots were, respectively, 2.2℃, 1.5℃ and 1.8℃ higher than those in the control plots, and 2.2℃, 0.9℃ and 1℃ higher in the field surface, and 1.5℃, 0.9℃ and 1.1℃ in the crop canopy. During the whole growing season of wheat, the seasonal and diurnal variations and trends of temperatures in warming plots were closely coupled with those in the control plots, indicating a objective simulation of the future climate warming. Experimental warming also decreased slightly the surface soil (0-20 cm) moisture with a decrement of 0.5%-2.2%, which was not significant compared to the control. Experimental warming with this FATI facility caused significant impacts on wheat growth duration. The durations from the sowing time to the heading stage were, respectively, shortened by 14, 9.5 and 11.5 days on an average in the AW, DW and NW plots during the two warming years, and the durations from the heading stage to the harvest were extended by 3, 3, and 2.5 days, respectively. 【Conclusion】 The experimental results indicate that this experimental warming facility is suitable to study the responses and adaptations of winter wheat to climate warming at system-level in situ, and that great efforts need to be made in the field experimental warming research to improve crop models for regional assessment of crop production under future climate.

Key words: climate warming, free air temperature increased system (FATI) system, diurnal warming scenario, winter wheat, food security