DOI: 10.5285/fbcfc877-a38e-4c26-8d8b-7226392493db
title: Soil nutrients, bulk density and pyrogenic carbon in permanent monitoring plots along altitudinal and forest perturbation gradients in the Colombian Andes, 2019-2022

description: The dataset contains information on soil nutrients including pH, available phosphorus, total phosphorus, texture analysis in sand, clay and silt, and exchangeable Ca, Mg, K, Na. Soil pyrogenic carbon, including Total Organic Carbon (TOC) (%C_(Bulk)), pyrogenic carbon D13C (lower, median, and upper), pyrogenic carbon (Cpyc), Cpyc%/CBulk, organic carbon and soil bulk density and dry weight of roots. The datasets include information about the plot location and parameters of the locality. The data were collected between 2019 and 2022 from 27 forest monitoring plots (0.5 ha each) in five locations along an altitudinal (lowland, mid-elevation, and highland forests) and forest perturbation (low, medium, and high perturbation levels) gradient in Andean ecosystems in Colombia. The objective of this data collection was to determine the change in soil characteristics between the disturbance gradients. This information is important for understanding the drivers of variation in forest resilience and the impacts of disturbance on ecosystem functioning.

This data set was obtained within the framework of the BioResilience project, a transdisciplinary investigation that seeks to understand the Resilience of forest ecosystems after the post-conflict period in Colombia. This research was supported by the UK Natural Environment Research Council Fund (NE/R017980/1).
description: Samples were analyzed in the laboratory of the National Open and Distance University (UNAD), Instituto Nacional de Pesquisas da Amazônia, and James Cook University. 

Total Organic Carbon (TOC) was calculated by elemental analysis using a Costech ECS-4010 with a zero blank autosampler. Pyrogenic carbon (Cpyc) was analyzed via hydrogen pyrolysis (HyPy). The ratio of pyrogenic carbon to total organic carbon (Cpyc%/CBulk) was determined by elemental analysis following HyPy, which quantifies the Stable Polycyclic Aromatic Carbon component of total PyC in a sample. Soil pH was determined by 10 grams of fine earth shaken with 25 ml of water for 1 hour on a circular shaker, followed by a 1-hour rest period. The pH of the supernatant was then measured using an automatic probe. Available phosphorus (p_available) were analyzed for a sequential extraction with reagents of increasing strength. The first step being resin extractable P, followed by 0.5 M NaHCO3,0.1MNaOH and 1M HCl. Total phosphorus (tot_p) was calculated by acid digestion using concentrate sulfuric acid followed by H2O2. Particle size analysis was undertaken using the Boyoucos method. 50 g of fine earth was first treated with physical and chemical dispersants and then separated into sand (particle sizes between 0.05 and 2 mm),silt (particle sizes between 0.002 mm and 0.05mm) and clay contents (particle sizes<0.002 mm) by the means of a series of hygrometer readings in a settling soil solution. Exchangeable Ca, Mg, K and Na were determined by the silver thiourea method (Ag-TU). This method allows an appropriate one-step centrifuge extraction using 0.01 M Ag-TU solution, which achieves complete cation exchange.

Samples for bulk density determinations were oven dried until constant weight, cooled to room temperature in a sealed desiccant before final weight determinations were made.