Responses of biomass growth and grain yield of midseason rice to the anticipated warming with FATI facility in East China

Crop model projections and historical data analyses have shown that global warming may cause serious decrease in crop productivity, however, many uncertainities remain on the impact quantification due to the unclear understanding of actual crop response. Therefore, we performed a three-year field warming experiment with free air temperature increase (FATI) facility to investigate the actual response of midseason rice growth in East China. There were four treatments (AW: all-day warming; DW: daytime warming; NW: nighttime warming; CK: ambient control) with three replicates. This FATI facility presented a good simulation of the local air temperature pattern with an increase in the daily mean temperature of about 1.1–2.0 °C during rice whole growth duration compared to the ambient control. Warming shortened the pre-heading phase respectively by 3.3 d, 1.7 d and 2.0 d in the AW, DW and NW plots, while the post-heading phase stayed almost unchanged. During the three years, warming slightly decreased the aboveground biomass by an average of 9.1%, 10.3% and 3.3%, and the grain yield by an average of 0.9%, 6.4% and 6.1% in the AW, DW and NW plots, respectively. Warming tended to decrease rice photosynthesis rate and stimulate the nighttime respiration rate. It also enlarged the flag leaf area and increased its chlorophyll content. No significant difference and interaction in the actual response of rice growth were found between the warming regimes. The above evidences suggest that the expected warming less than 2.0 °C may not cause significant decrease in rice productivity in East China.

► A three-year warming experiment was conducted to learn midseason rice responses. ► 1.5 °C warming tended to decrease rice biomass growth and grain yield. ► There was no significant difference in the effect size of different warming regimes. ► Modeling might over-estimated the warming impacts on midseason rice productivity.