Contrasting responses of fine root biomass and traits to large-scale nitrogen and phosphorus addition in tropical forests in the Guiana shield
Data files
Dec 14, 2023 version files 14.47 KB
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Dryad_FG_LFL_OIKOS2023.csv
10.28 KB
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README.md
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Abstract
Fine roots mediate plant nutrient acquisition and growth. Depending on soil nutrient availability, plants can regulate fine root biomass and morphological traits to optimise nutrient acquisition. Little is known, however, about the importance of these parameters influencing forest functioning. In this study, we measured root responses to nutrient additions to gain a mechanistic understanding of plant adaptations to nutrient limitation in two tropical forests in French Guiana, differing two-fold in their soil nutrient statuses. We analysed the responses of root biomass, mean root diameter (RD), specific root length (SRL), specific root area (SRA), root tissue density (RTD) and carbon (C), nitrogen (N) and phosphorus (P) concentrations in roots down to 15 cm soil depth after three years of N and P additions. At the lower-fertility site Paracou, no changes in root biomass or morphological traits were detected with either N or P addition, although P concentrations in roots increased with P addition. In the higher fertility site, Nouragues, root biomass and P concentrations in roots increased with P addition, with no changes in morphological traits. In contrast, N addition shifted root traits from acquisitive to more conservative by increasing RTD. A significant interaction between N and P in Nouragues pointed to stronger responses to P addition in the absence of N. Our results suggest that the magnitude and direction of root biomass and trait expression were regulated by soil fertility, corroborated by the response to N or P additions. At low fertility sites, we found lower plasticity in root trait expression compared to more fertile conditions, where N and P additions caused stronger and antagonistic responses. Identifying the exact role of mechanisms affecting root nutrient uptake in Amazon forests growing in different soils will be crucial to foresee if and how rapid global changes can affect their carbon allocation.
README: Contrasting responses of fine root biomass and traits to large-scale nitrogen and phosphorus addition in tropical forests in the Guiana shield
https://doi.org/10.5061/dryad.v15dv4231
Data regarding fine root (roots smaller than 2 mm in diameter) biomass stocks, root morphological traits, and nutrient concentration and stocks in fine roots and soils down to 15 cm depth in two forests in French Guiana. Data were sampled in the dry and wet seasons of 2019. These two forests received 3 years of factorial nutrient addition, with control plots and plots with the addition of nitrogen, phosphorus and nitrogen and phoshorus in combination. Each site comprises 12 plots (3 per treatment) measuring 50 x 50 m, and in each plot, 5 samples were collected in each season, in the inner 30 x 30 m. These data therefore, report belowground data from the two sites belonging to the large-scale nutrient fertilisation IMBALANCE-P.
Description of the data and file structure
The data consist of one table with 32 columns and below the abbreviations and units are described in detail.
Site: Two study sites in French Guiana; Paracou (PAR) and Nouragues (NOU)
Topo: Three different terrain topographies frm which data was collected (bottom plots, slope plots and Top plots)
Treat: four different treatments applied for each site and topographies. C is for control plots without nutrient addition; N is for plots with nitrogen addition; P is for plots with phosphorus addition and NP is for plots with the addition of both nitrogen and phorphorus together
Plot_n: refers to the treatments in a numerical form. 1 refers to N treatment plots, 2 refers to NP treatment plots, 3 for P plots and 4 for control plots.
Date: Date that samples were collected in the field (ex. 201905, May 2019)
Season: Seasons of sampling; dry and wet
N_treat: Presence (1) and absence (0) of nitrogen addition
P_treat: Presence (1) and absence (0) of phosphorus addition
mean_finerootstocks_Mg_ha: Fine root (<2mm diameter) biomass stocks down to 15 cm soil depth in Mg/ha
mean_Cstock_Mg_ha: Fine root (<2mm diameter) biomass stocks of carbon down to 15 cm soil depth in Mg/ha
mean_Nstock_kg_ha: Fine root (<2mm diameter) biomass stocks of nitrogen down to 15 cm soil depth in kg/ha
mean_Castock_kg_ha: Fine root (<2mm diameter) biomass stocks of calcium down to 15 cm soil depth in kg/ha
mean_Mgstock_kg_ha: Fine root (<2mm diameter) biomass stocks of magnesium down to 15 cm soil depth in kg/ha
mean_Kstock_kg_ha: Fine root (<2mm diameter) biomass stocks of potassium down to 15 cm soil depth in kg/ha
mean_Pstock_kg_ha: Fine root (<2mm diameter) biomass stocks of phosphorus down to 15 cm soil depth in kg/ha
mean_diam_mm: Mean fine root diameter in mm
mean_SRL_m_g: Specific root length in m/g
mean_SRA_cm2_g: Specific root area in cm2/g
mean_RTD_g_cm3: Root tissue density in g/cm3
mean_C_root_%: Carbon concentration in fine roots in %
mean_N_root_%: Nitrogen concentration in fine roots in %
mean_Ca_root_mg_kg: Calcium concentration in fine roots in mg/kg
mean_Mg_root_mg_kg: Magnesium concentration in fine roots in mg/kg
mean_K_root_mg_kg: Potassium concentration in fine roots in mg/kg
mean_P_root_mg_kg: Phosphorus concentration in fine roots in mg/kg
NP_ratio_root: Ratio nitrogen to phosphorus concentrations in fine roots
CP_ratio_root: Ratio carbon to phosphorus concentrations in fine roots
mean_Csoil_%: Carbon concentration in soils down to 15 cm in %
mean_Nsoil_%: Nitrogen concentration in soils down to 15 cm in %
mean_Psoil_mg_kg: Phosphorus concentration in soils down to 15 cm in mg/kg
Pstock_soil_kg_ha: Phosphorus stocks in soils down to 15 cm in kg/ha
mean_bulk_g_cm3: Soil bulk density down to 15 cm in g/cm3
NA in table cells denote data not available.
Sharing/Access information
Data from aboveground responses to nutrient addition in the same plots and sites, used in the supplementary material of this manuscript, can be found in full at: