1. The Growth and N Retention of Two Annual Desert Plants Varied Under Different Nitrogen Deposition Rates.
- Author
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Cui, Xiaoqing, Yue, Ping, Wu, Wenchao, Gong, Yanming, Li, Kaihui, Misselbrook, Tom, Goulding, Keith, and Liu, Xuejun
- Subjects
DESERT plants ,ANNUALS (Plants) ,PLANT biomass ,HABITAT partitioning (Ecology) ,PLANT variation ,PLANT-soil relationships - Abstract
Nitrogen (N) partitioning between plant and soil pools is closely related to biomass accumulation and allocation, and is of great importance for quantifying the biomass dynamics and N fluxes of ecosystems, especially in low N-availability desert ecosystems. However, partitioning can differ among species even when growing in the same habitat. To better understand the variation of plant biomass allocation and N retention within ephemeral and annual species we studied the responses of Malcolmia Africana (an ephemeral) and Salsola affinis (an annual) to N addition, including plant growth, N retention by the plant and soil, and N lost to the environment using
15 N (double-labeled15 NH4 15 NO3 (5.16% abundance) added at 0, 0.8, 1.6, 3.2, and 6.4 g pot-1 , equivalent to 0, 15, 30, 60, and 120 kg N ha-1 ) in a pot experiment. Higher N addition (N120) inhibited plant growth and biomass accumulation of the ephemeral but not the annual. In addition, the aboveground:belowground partitioning of N (the R:S ratio) of the ephemeral decreased with increasing N addition, but that of the annual increased. The N input corresponding to maximum biomass and15 N retention of the ephemeral was significantly less than that of the annual. The aboveground and belowground retention of N in the ephemeral were significantly less than those of the annual, except at low N rates. The average plant–soil system recovery of added15 N by the ephemeral was 70%, significantly higher than that of the annual with an average of 50%. Although the whole plant–soil15 N recovery of this desert ecosystem decreased with increasing N deposition, our results suggested that it may vary with species composition and community change under future climate and elevated N deposition. [ABSTRACT FROM AUTHOR]- Published
- 2019
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