Beyond total carbon: conversion of amazon forest to pasture alters indicators of soil C cycling
| Autor: | Fernando Dini Andreote, Jorge L. M. Rodrigues, Ademir Durrer, Brendan J. M. Bohannan, Andrew J. Margenot, Sanjai J. Parikh, Klaus Nüsslein, Joost van Haren, Lucas C. R. Silva |
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| Rok vydání: | 2021 |
| Předmět: |
geography
Topsoil geography.geographical_feature_category 010504 meteorology & atmospheric sciences Chronosequence USO DO SOLO 04 agricultural and veterinary sciences Soil carbon Old-growth forest 01 natural sciences Soil quality Agronomy Deforestation 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Environmental Chemistry Environmental science Secondary forest sense organs Cycling 0105 earth and related environmental sciences Earth-Surface Processes Water Science and Technology |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | It is well established that land use change (LUC) can impact soil organic carbon (SOC) in tropical regions, but the long-term effects of LUC on soil quality and C cycling remain unclear. Here, we evaluated how LUC affects soil C cycling in the Amazon region using a 100-year observational chronosequence spanning primary forest-to-pasture conversion and subsequent secondary forest succession. We found a surprising increase in topsoil SOC concentrations 60 years following conversion, despite major losses (> 85%) of forest-derived SOC within the first 25 years. Shifts in molecular composition of SOC, identified with diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, occurred in tandem with a significant decline in permanganate-oxidizable C (POXC) and β-glucosidase activity (per unit SOC), interpreted as a deceleration of soil C cycling after pasture grasses became the dominant source of C inputs to soil. Secondary forest succession caused rapid reversal to conditions observed under primary forest for β-glucosidase activity but not for SOC molecular composition (DRIFT spectroscopy), reflecting a long-lasting effect of LUC on soil C cycling. Our results show that rapid changes in the origin of SOC occur following deforestation with legacy effects on some indicators of C cycling (e.g. enzyme activity) but not others (e.g. molecular composition). This approach offers mechanistic understanding of LUC in the Amazon basin and can be used to help explain conflicting reports on how deforestation impacts SOC in the region. |
| Databáze: | OpenAIRE |
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