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21 results for “foliar nitrogen”
Foliar and Soil Chemistry at Harvard Forest Chronic Nitrogen Amendment Experiment 1995-2009
The aim of the chronic N study at Harvard Forest is to increase our understanding of ecosystem nitrogen dynamics in response to elevated nitrogen inputs. In recent, nitrogen deposition in the Northeastern United States has been 10 to 20 times above historic background levels which could possibly saturate the retention capacity of a forest ecosystem. Long-term elevated N deposition typically leads to an increase in the concentration of total foliar N, with or without similar changes in the important base elements such as Ca, Mg and K. This increase in leaf N content also leads to significant shifts in the internal partitioning of N within the leaf. For example, in conifers, N deposition has been shown to significantly increase leaf N present in the form of free amino acids such as arginine. Little is known about N partitioning for hardwoods under these conditions. These changes in N partitioning are possibly connected to leaf function. The present study was conducted to experimentally test whether the alterations in N partitioning do occur due to long-term N deposition and if so do they have a positive or a negative effect on photosynthetic capacity and biomass production. A possible decoupling of the relationship between foliar N and photosynthetic rate may occurs under these conditions. The treatment plots used in this study are part of the Chronic Nitrogen Amendment Study at the Harvard Forest LTER site (42.5°N, 72°W). The site has a temperate climate with monthly temperatures ranging from -7°C in January to 20°C in July. Average annual precipitation is 110 cm (http://harvardforest.fas.harvard.edu). The site averages approximately 8 kg ha-1 year-1 of total N deposition. As reported earlier, the land-use history of the pine and hardwood stands used in this study is very different. Two adjacent stands were chosen for the study: an even-aged red pine (Pinus resinosa Ait.) stand and a 50-year-old mixed hardwood stand that had regenerated naturally after clearcutting i
Hubbard Brook Nitrogen Oligotrophication (HBNO): Foliar resorption, leaf mass per area, and leaf chemistry of sugar maple and American beech, 2020-2022
We quantified nitrogen (N) resorption of the two dominant tree species of northern hardwood forests along an elevation gradient using 14 sites at Hubbard Brook Experimental Forest, NH. For these calculations, we also quantified the leaf mass per area for both species, sugar maple and American beech. The original data before averaging for combining with chemistry data is available in an earlier revision of this dataset. Foliar N of sugar maple increased, and N resorption proficiency (NRP) decreased with increasing elevation. In contrast, foliar N and NRP of American beech did not vary significantly with elevation, suggesting that the mechanisms driving patterns of N resorption were distinct between these co-occurring species. While both species exhibited strong correlations between resorption efficiency of C and N, resorption of both elements was much greater for beech than maple. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
Soil and foliar carbon and nitrogen content and stable isotope ratios from rainfall manipulation experiments at the Jornada Basin LTER, 2011-2020
As rainfall extremes are expected to increase in novel magnitude and frequency, especially in dryland regions, we asked how prolonged and directional shifts to water availability may affect ecosystem carbon and nitrogen dynamics. This data set includes foliar and soil carbon and nitrogen stable isotope and concentration data collected from multiple long-term rainfall manipulation experiments at the Jornada Basin LTER. Datasets also include rainfall data adjusted to rainfall manipulation intensities. Collection dates range from 5 to 14 years since the onset of experimental treatments. The primary plant species targeted for this study were the dominant grass, Bouteloua eriopoda, and the dominant shrub, Prosopis glandulosa.
Macroscale Variation in Red Maple (Acer rubrum) Foliar Carbon, Nitrogen, and Nitrogen Resorption
Project Description The primary goal of this project was to investigate intraspecific variation of foliar nitrogen resorption for Acer rubrum (red maple). In particular, we are interested in examining whether foliar nutrient resorption is related to climatic factors such as mean annual temperature and/or precipitation. The approach used to collect green and fallen leaf samples was through a community science project where participants sent leaves to our lab at Boston University for analysis. In the spring/summer of 2019 plant and naturalist organizations throughout the range of red maple in the United States were contacted to request information about this project be sent to their members regarding the collection of red maple leaves for the study. Interested parties were prompted to complete a google form that included basic contact information. Each participant was then sent a sampling kit which included gloves, sampling protocols, and data sheets. For each set of leaves collected from a single tree they were assigned the following identification “tasper-###” where the numbers were uniquely assigned. Green and fallen leaves were assigned different “tasper-###” numbers. Within a single identification (e.g., tasper-120) each leaf was individually assigned a letter a-n, where n corresponds to the letter of how many leaves were sent from that tree. For most samples a-j was obtained because we asked participants to collect 10 leaves. Individual leaves were scanned for area analysis using a flatbed scanner at 300 dpi and weighed. For C&N analysis each leaf blade from a set of green or fallen leaves from a single tree was hole-punched and the samples were combined yielding one C and N concentration per tree for both each green and fallen leaves. Punches were ground and homogenized to a powder using a mortar and pestle. Approximately 3 mg of dried sample was analyzed for C and N concentration using a NC2500 elemental analyzer (CE Elantech, Lakewood, NJ, USA). NIST Apple Le
Figure 2. Green and senescence N in Foliar resorption of nitrogen and phosphorus in Alcea apterocarpa (Malvaceae) in different habitats types
Figure 2. Green and senescence N:P ratio of A. apterocarpa in different habitat types. Means followed by the same letter are not significantly different at the 0.05 level using Tukey's HSD test.
Figure 1 in Foliar resorption of nitrogen and phosphorus in Alcea apterocarpa (Malvaceae) in different habitats types
Figure 1. Resorption proficiency and efficiency levels of A. apterocarpa according to all patterns. Habitat abbreviations are H1: riverbank, H2: meadow and H3: forest clearing. Minor letters followed by the same letter are not significantly different at the 0.05 level using Tukey's HSD test.
Global change progressively increases foliar nitrogen–phosphorus ratios in China's subtropical forests
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Climate Change Across Seasons Experiment (CCASE) Sapling Study at the Hubbard Brook Experimental Forest: Foliar Nitrogen
Foliar nitrogen concentrations of red maple and sugar maple saplings experiencing combinations of soil warming and winter freeze-thaw cycles were measured during the growing season of 2014 and 2015 as an indicator of plant nitrogen status. There were seven treatments for each species of maple. For each species, ten saplings experienced ambient temperatures (reference), ten experienced growing season warming with no induced freeze-thaw cycles in winter (warmed), ten in each of four groups experienced warming in the growing season coupled with two, four, six, or eight soil freeze-thaw cycles in winter (warmed + 2 FTC, warmed + 4 FTC, warmed + 6 FTC, warmed + 8 FTC), and ten experienced snow removal in winter with ambient temperatures in the growing-season (snow removal). These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
Climate Change Across Seasons Experiment (CCASE) at the Hubbard Brook Experimental Forest: Foliar Nitrogen and Natural Abundance Nitrogen Isotopic Composition
Foliar nitrogen and natural abundance stable isotopes of nitrogen in foliage were measured on all Climate Change Across Seasons Experiment (CCASE) plots. There are six plots total (each 11 x 14 m). Two are warmed 5 degrees C throughout the growing season (Plots 3 and 4). Two others are warmed 5 degrees C in the growing season and have snow removed during winter to induce soil freezing and then warming cables turn on to create thaws; each soil freeze/thaw cycle includes 72-hours of soil freezing followed by 72-hours of thaw (Plots 5 and 6). Four kilometers (2.5 mi) of heating cable are buried in the soil to warm these four plots. Two additional plots serve as controls for our experiment (Plots 1 and 2). This data set includes foliar nitrogen and natural abundance stable isotopes of nitrogen in foliage from 2012 to 2018. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
Climate Change Across Seasons Experiment (CCASE) at the Hubbard Brook Experimental Forest; concentrations of foliar metabolites: polyamines, amino acids, chlorophyll, carotenoids, soluble proteins, soluble elements, sugars, and total nitrogen and carbon in red maple (Acer rubrum) trees.
Foliage was collected in 2015 and 2017 from red maple trees at the Climate Change Across Seasons Experiment (CCASE) as part of the Hubbard Brook Ecosystem Study (HBES). Analyses of foliar metabolites include polyamines, amino acids, chlorophylls, carotenoids, soluble proteins, soluble inorganic elements, sugars, and total nitrogen and carbon. There are six (11 x 14m) plots in total in this study; two control (plots 1 and 2), two warmed 5 degrees (°) Celsius (C) above ambient throughout the growing season (plots 3 and 4), and two warmed 5 °C in the growing season, with snow removal during the winter to induce soil freezing and then warmed with buried heating cables to create a subsequent thaw (plots 5 and 6). Each soil freeze/thaw cycle includes 72 hours of soil freezing followed by 72 hours of thaw. Four kilometers (km) of heating cable are buried in the soil to warm these four plots. Together, these treatments led to warmer growing season soil temperatures and an increased frequency of soil freeze-thaw cycles (FTCs) in winter. Our goal was to determine how these changes in soil temperature affect foliar nitrogen (N) and carbon metabolism of red maple trees. These data were gathered as a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
Figure 4. Regression between senescence leaf N in Foliar resorption of nitrogen and phosphorus in Alcea apterocarpa (Malvaceae) in different habitats types
Figure 4. Regression between senescence leaf N/P ratio and RE and RP of A. apterocarpa.
Figure 3. Regression between green leaf N in Foliar resorption of nitrogen and phosphorus in Alcea apterocarpa (Malvaceae) in different habitats types
Figure 3. Regression between green leaf N/P ratio and RE and RP of A. apterocarpa.
Data from: Long-term drought triggers contrasting responses of foliar stable nitrogen isotopes and soil available nitrogen in a subtropical forest
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Foliar nitrogen at the Hubbard Brook Experimental Forest and surrounding areas in the White Mountains, NH, 2004-2014
This data set includes foliar nitrogen content of leaf samples collected at Hubbard Brook Experimental Forest and on two additional plots within the White Mountain National Forest from 2004-2014. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
Nitrogen enrichment and foliar fungal pathogens affect the mechanisms of multispecies plant coexistence
<p>This is the data and code repository for the manuscript entitled "Nitrogen enrichment and foliar fungal pathogens affect the mechanisms of multispecies plant coexistence".</p> <p>DATA:</p> <p><strong>data.txt</strong></p> <p>Dataset collected in the PaNDiv experiment, a large field experiment in Münchenbuchsee (near Bern) which investigates the mechanisms by which nitrogen enrichment affects ecosystem functioning. The dataset is composed by the following elements:</p> <ul> <li><em>year </em>--- 2017 or 2018</li> <li><em>block </em>--- experimental block in the PaNDiv experiment (1, 2, 3 or 4)</li> <li><em>plot </em>--- experimental plot in the PaNDiv experiment (from 1 to 336)</li> <li><em>nitrogen </em>--- addition of nitrogen to the soil (0 = no, 1 = yes)</li> <li><em>fungicide </em>--- application of fungicide to the vegetation (0 = no, 1 = yes)</li> <li><em>treatment</em> --- control, nitrogen addition, fungicide application, and their combined effect</li> <li><em>number</em> --- replicate number of the focal species; numbers are repeated because it restarts with each target focal-neighbour species combination (not shown)</li> <li><em>focal_sp</em> --- 8 possible species: <ul> <li>tar_off = <em>Taraxacum officinale</em></li> <li>cre_bie = <em>Crepis biennis</em></li> <li>rum_ace = <em>Rumex acetosa</em></li> <li>dac_glo = <em>Dactylis glomerata</em></li> <li>ant_odo = <em>Anthoxanthum odoratum</em></li> <li>cen_jac = <em>Centaurea jacea</em></li> <li>sal_pra = <em>Salvia pratensis</em></li> <li>pla_med = <em>Plantago media</em></li> </ul> </li> <li><em>biomass_i </em>--- initial biomass of the focal plant (start of the growing season; February/March)</li> <li><em>biomass_f</em> --- final biomass of the focal plant (end of the growing season; June)</li> <li><em>tar_off</em> --- visually estimated cover for this species as a neighbour</li> <li><em>cre_bie</em> --- visually estimated cover for this species as a neighbour</li> <li><em>rum_ace</em> --- visually estimated cover for this species as a neighbour</li> <li><em>dac_glo</em> --- visually estimated cover for this species as a neighbour</li> <li><em>ant_odo</em> --- visually estimated cover for this species as a neighbour</li> <li><em>cen_jac</em> --- visually estimated cover for this species as a neighbour</li> <li><em>sal_pra</em> --- visually estimated cover for this species as a neighbour</li> <li><em>pla_med</em> --- visually estimated cover for this species as a neighbour</li> <li><em>herbs </em>--- visually estimated cover for non-target herb species in the PaNDiv experiment</li> <li><em>grasses </em>--- visually estimated cover for non-target grass species in the PaNDiv experiment</li> <li><em>legumes </em>--- visually estimated cover for non-target legume species in the PaNDiv experiment</li> </ul> <p> </p> <p>CODE:</p> <p><strong>001-optimx.R</strong></p> <p>Code that uses maximum likelihood to fit population models to the data. Produces several datasets with model coefficients and AIC values.</p> <p> </p> <p><strong>002-model_sel_coefs.R</strong></p> <p>Code to select the coefficients based on the best model and add the size effect of the focal plants when needed. Creates all interaction matrices and intrinsic growth rate vectors.</p> <p> </p> <p><strong>003-final_matrices.R</strong></p> <p>Code to adjust the matrices for coexistence computing.</p> <p> </p> <p><strong>004-coexistence.R</strong></p> <p>Computes structural coexistence outputs. Provides a clean dataset with structural niche differences, structural fitness differences, and other multispecies coexistence metrics.</p>
Enhanced foliar 15N enrichment with increasing nitrogen addition rates: Role of plant species and nitrogen compounds
<p>Determining the abundance of N isotope (δ15N) in natural environments is a simple but powerful method for providing integrated information on the N cycling dynamics and status in an ecosystem under exogenous N inputs. However, whether the input of different N compounds could differently impact plant growth and their 15N signatures remains unclear. Here, the response of δ15N signatures and growth of three dominant plants (Leymus chinensis, Carex duriuscula, and Thermopsis lanceolata) to the addition of three N compounds (NH4HCO3, urea, and NH4NO3) at multiple N addition rates were assessed in a meadow steppe in Inner Mongolia. The three plants showed different initial foliar δ15N values because of differences in their N acquisition strategies. Particularly, T. lanceolata (N2-fixing species) showed significantly lower 15N signatures than L. chinensis (associated with arbuscular mycorrhizal fungi, AMF) and C. duriuscula (associated with AMF). Moreover, the foliar δ15N of all three species increased with increasing N addition rates, with a sharp increase above an N addition rate of ~10 g N m-2yr-1. Foliar δ15N values were significantly higher when NH4HCO3 and urea were added than when NH4NO3 was added, suggesting that adding weakly acidifying N compounds could result in a more open N cycle. Overall, our results imply that assessing the N transformation processes in the context of increasing global N deposition necessitates the consideration of N deposition rates, forms of the deposited N compounds, and N utilization strategies of the co-existing plant species in the ecosystem.<span> </span></p>
Data from: Species-specific responses of foliar nutrients to long-term nitrogen and phosphorus additions in a lowland tropical forest
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Enhanced foliar 15N enrichment with increasing nitrogen addition rates: Role of plant species and nitrogen compounds
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Data from: Differential effects of soil chemistry on the foliar resorption of nitrogen and phosphorus across altitudinal gradients
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Data from: Foliar fungal pathogen inhibition increases ecosystem carbon sequestration independently of nitrogen enrichment in a Tibetan alpine meadow
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