(1) 中国科学院烟台海岸带研究所中国科学院海岸带环境过程与生态修复重点实验室

To reveal the biomass changes of Suaeda glauca and Suaeda salsa as reciprocal companion under different additive amount of extraneous nitrogen, a field simulation experiment was conducted in the Yellow River Delta ecology research station of coastal wetland from May 2 to June 27, 2017. The two species were transplanted in to PVC pipe, with overall 108 PVC pipes laid. There were 3 planting densities (4 plants of dominant with 1 plant of companion, 2 plants of dominant with 1 plant of companion, and only 1 plant of dominant) were set in the experiment. Considering the situation of nitrogen deposition in the Yellow River Delta, 3 kinds of additive amount of extraneous nitrogen (0 g/m~2 nitrogen, 15 g/m~2 nitrogen, 30 g/m~2 nitrogen) were set, urea was as the nitrogen resource of extraneous nitrogen. The results showed that the average biomass accumulation of Suaeda salsa and Suaeda glauca both enhanced significantly along with increasing extraneous nitrogen input when planted 4 plants of dominant and 2 plants of dominant in each PVC pipe. When the additive amount of extraneous nitrogen were 15 g/m~2 nitrogen and 30 g/m~2 nitrogen, the biomass of Suaeda glauca was (58.0502.560) g per plant and (58.7403.170) g per plant, which were both significantly higher than that [(20.8500.640) g per plant] without extraneous nitrogen addition. The biomass of Suaeda salsa was (82.6401.330) g per plant and (111.9606.400) g per plant separately when the additive amount of extraneous nitrogen was 15 g/m~2 nitrogen and 30 g/m~2 nitrogen, which were also both significantly higher than that [(37.5001.750) g per plant] without extraneous nitrogen addition. Increasing additive amount of extraneous nitrogen promoted the biomass accumulation of Suaeda glauca and Suaeda salsa with an higher increase degree of the biomass of Suaeda salsa, indicating that increasing extraneous nitrogen promoted the growth of Suaeda salsa more strongly.