大气CO2浓度升高对植物及土壤氮素影响的Meta分析OA

To systematically assess the effects of elevated CO2 concentrations on plant growth and development as well as soil nitrogen availability,this study conducted a Meta-analysis of 3 607 observations extracted from 43 Chinese and English publications.The analysis quantified plant-soil nitrogen responses under varying CO2 levels and nitrogen fertilizer management regimes.The results indicate that the effects of elevated CO2 concentration on NH+4-N content in the surface layers(0-20 cm)of different landuse types were different.In upland soils,NH+4-N increased by 22%when CO2 concentrations exceeded 700 μmol·mol-1,whereas NO-3-N concentrations generally declined by 25%.When CO2 concentrations ranged from 500 to 700 μmol·mol-1,absorbing nitrogen amount by wetland and upland plants increased by 19%and 14%,respectively,while nitrogen use efficiency increased by 6%and 2%;these stimulatory effects weakened at concentrations above 700 μmol·mol-1.Nitrogen application rates strongly regulated plant nitrogen content responses:moderate fertilization(150-300 kg·hm-2)alleviated the suppressive effects of elevated CO2 on nitrogen content,while insufficient(<150 kg·hm-2)or excessive(>300 kg·hm-2)nitrogen inputs led to decreases in nitrogen content.The study revealed that the response of plant and soil nitrogen to elevated CO2 concentration was regulated by plant type,nitrogen application level and experimental conditions.In the future,it is necessary to combine multi-factor comprehensive research to formulate differentiated agricultural adaptation strategies.