关键词: 气候变化, 温度升高, CO₂浓度升高, 冬小麦生育期, 土壤N、P含量

Abstract: T-FACE (temperature-free air carbon dioxide enrichment）experimental platform was adopted. Four field treatments of winter wheat were set: field conventional temperature and CO₂ concentration (CK), field conventional temperature and increase CO₂ concentration to 575μmol·L⁻¹ (C), field increase temperature (i.e., 2℃ above atmospheric temperature) and field conventional CO₂ concentration (T), and field increase temperature (i.e., 2℃ above atmospheric temperature) and increase CO₂ concentration to 575μmol·L⁻¹ (CT) . Soil samples were collected at different soil layers (plough layer 0−14cm, plough bottom 14−33cm, pond layer 33−59cm and glebe layer 59−80cm) at sowing stage, overwintering stage, tillering stage and maturity stage of winter wheat, respectively, to analyze the effects of increasing atmospheric CO₂ concentration and temperature on N and P content and availability in the soil. The results were as follows: (1)under the condition that CO₂ concentration increased in the overwintering stage of winter wheat, the nitrate nitrogen content in pond layer of soil showed a tendency to decrease by increasing temperature. In the overwintering stage of winter wheat, except for T treatment, the nitrate nitrogen content of CK, C and CT treatment was lower than that of tilling layer during sowing stage. In the overwintering stage of winter wheat, the nitrate nitrogen content increased most obviously in CK treatment. (2) Under the condition of increasing CO₂ concentration and temperature, the content of ammonium nitrogen in the soil at tillering stage and overwintering stage of winter wheat was significantly lower than that under normal CO₂ concentration and temperature treatment. There was no obvious upward or downward trend in different soil layers. The content of ammonium nitrogen was relatively stable during the whole growing stage of winter wheat. However, under CT, C and T treatments, the content of ammonium nitrogen increased significantly at maturity stage of winter wheat, and the increasing trend of nitrate nitrogen was more significant under increasing temperature (P<0.05). During the whole growth stage of winter wheat, the ammonium nitrogen showed a trend of increasing first and then decreasing under C treatment, while CK, CT and T treatments showed a trend of increasing, decreasing and increasing. (3) The content of available P in CK treatment was significantly higher than other treatments in the whole growth stage of winter wheat. There was a significant difference in available P content between CK treatment and CT and T treatments at sowing stage, overwintering stage and tillering stage of winter wheat (P<0.05). The results can provide some scientific basis for rational application of N and P fertilizer, reducing unnecessary nutrient loss and preventing non-point source pollution under the condition of CO₂ concentration and temperature increase caused by climate change in the future.

Key words: Climate change, Increase temperature, Increase CO₂ concentration, Winter wheat growth period, N and P contents in the soil