Contrasting responses of fine root biomass and traits to large-scale nitrogen and phosphorus addition in tropical forests in the Guiana shield

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 ..., , , # Contrasting responses of fine root biomass and traits to large-scale nitrogen and phosphorus addition in tropical forests in the Guiana shield

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 abbrevia...