Divergent Responses of Foliar N:P Stoichiometry During Different Seasons to Nitrogen Deposition in an Old-Growth Temperate Forest, Northeast China

Abstract

Atmospheric nitrogen (N) deposition has rapidly increased during the last few decades; however, the seasonal responses of leaf N:P stoichiometry to N deposition remain unclear. In 2008, a simulated N deposition experiment (0, 30, 60, and 120 kg·N·ha−1·yr−1) was conducted in an old-growth temperate forest in Northeast China. In 2014, the leaves of 17 woody species and soil were sampled in spring, summer, and autumn in each treatment, and N:P stoichiometry was assessed. Community N and P in summer were significantly lower than that in spring and autumn. Unlike broadleaved species, conifers showed no significant variation among the three seasons. N addition significantly enhanced community N and soil available P but decreased soil total P in summer and autumn, and decreased community P, as well as the P concentration of three life forms (conifer, tree, and shrub), in autumn. Our results emphasize the importance of multiple sampling across seasons in temperate forests. Arguing against the traditional consensus, the productivity of the old-growth temperate forests is limited by both N and P.

Interactive climate-soil forces shape the spatial distribution of foliar N:P stoichiometry in Vaccinium uliginosum planted in agroforests of Northeast China

“…Our foliar N:P ratio of V. uliginosum was lower than 4.4, which was also lower than that in previous studies (Koerselman and Meuleman, 1996;Goransson et al, 2014). Our N:P ratio was also lower than that in other shrubs in temperate agroforests of northeast China (>6.0) Yang et al, 2019), grasslands across mainland China (>20.0) (Song et al, 2014), and pine forests in warm temperate climates (>8.0) (Wang et al, 2018). These differences suggest that V. uliginosum suffered a relatively higher N limit in the agroforests of northeast China.…”

“…Temperate forests in the Northern Hemisphere are probably subjected to an N limit due to a shorter chronicle of soils and a lower cycle rate than other ecosystems located in warmer climates (Reich and Oleksyn, 2004;Suo et al, 2016;Ding et al, 2021). Temperate old-growth forests may have also been suffering co-limits of low N and P availabilities (Yang et al, 2019). When P is supplied sufficiently, the relative N deficit occurs for all botanic life forms in temperate forests (Wang et al, 2018;Yang et al, 2019;Zhang et al, 2020).…”

“…Temperate old-growth forests may have also been suffering co-limits of low N and P availabilities (Yang et al, 2019). When P is supplied sufficiently, the relative N deficit occurs for all botanic life forms in temperate forests (Wang et al, 2018;Yang et al, 2019;Zhang et al, 2020). Given that the foliar N:P ratio of a specific plant species is shaped by changes in its acclimation to a synthesis of dual climate and soil forces, its spatial distribution can be modeled by geographical patterns of driving factors even at the global scale (Gao et al, 2022;Vallicrosa et al, 2022).…”

The Rhizosphere Functional Microbial Community: A Key Driver of Phosphorus Utilization Efficiency in Karst Forest Plants

“…We further calculated the leaf N:P ratio and the P:N ratio. The N:P ratio was used to reveal the limiting element for plant growth (N or P) [56,57]. While the P:N ratio represents the plant P utilization efficiency index (PPEI) growing in terrestrial ecosystems [51].…”

“…In analyzing the N and P contents and their corresponding N:P ratio, the limiting elements of organism growth, development, and reproduction can be effectively identified [88]. For example, the green leaf N:P ratio serves as a strong indicator of the relative nutrient availability to plants and has been extensively studied at regional and global levels in terrestrial ecosystems [56,57]. Generally, a leaf N:P < 14, between 14-16, and >16 indicate plant N limitation, N and P co-limitation, and P limitation, respectively [89].…”