1. Soil nitrate mediates the responses of plant community production to the frequency of N addition in a temperate grassland: a decadal field experiment.
- Author
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Song, Changchun, Zhang, Yuqiu, Ren, Zhengru, Lu, Haining, Chen, Xu, Liu, Ruoxuan, Chen, Jungang, and Zhang, Yunhai
- Subjects
PLANT communities ,FIELD research ,GRASSLANDS ,PLATEAUS ,ATMOSPHERIC deposition ,SOIL moisture - Abstract
Purpose: Nitrogen (N) enrichment through either artificial N application or atmospheric N deposition often increases ecosystem aboveground net primary productivity (ANPP). Therefore, results from N addition experiments have been used to assess the effects of atmospheric N deposition on ecosystems. However, the frequency of atmospheric N deposition is higher than that of artificial N addition. Whether the frequency of N addition alters the long-term response of ecosystem ANPP remains unclear. Methods: We conducted a N addition frequency experiment from 2010 in a temperate grassland, northern China. Plant community ANPP was collected in 2019 and 2020, and soil physicochemical properties were measured in 2020. Results: Plant community ANPP was significantly enhanced by N addition, whereas these increments declined with the frequency of N addition. The responses of the grasses ANPP were similar to those of the plant community ANPP. Forbs ANPP was not significantly altered. Meanwhile, soil ammonium and nitrate (NO
3 − –N) concentrations decreased with increasing N addition frequency, while the soil water content (SWC) and pH were similar among the frequencies of N addition. Regardless of the frequency of N addition, SWC and soil NO3 − –N jointly promoted grasses ANPP, ultimately increasing the plant community ANPP. Conclusion: Our findings demonstrate that the frequency of N addition affects plant community biomass production through altering soil nitrate concentration in the semi-arid grassland. Therefore, this study illustrates that a higher frequency of N addition is more suitable for assessing the long-term impacts of atmospheric N deposition on ecosystems. [ABSTRACT FROM AUTHOR]- Published
- 2023
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