Abstract: To better understand the effects of excessive nitrogen (N) absorption on plant growth, three N fertilization treatments were installed to measure the plant N content, dark respiration rate, biomass, and relative growth rate (RGR) of halophyte (Kochia scoparia) during its growth period. Under the conditions of excessive N absorption, the excessive N had minor effects on the dark respiration rate, resulting in the low N use efficiency during dark respiration. There was a highly linear correlation between mass-based dark respiration rate and RGR, and this correlation was consistent across different N treatments. An allometric relationship was observed between dark respiration rate and plant N content, and the relationship was correlated with N application rate, i.e., the higher the N application rate, the smaller the scaling exponent.

Key words: buffering zone, Ecopath with Ecosim (EWE) model, wetland ecosystem, trophic level, system features.