Deforestation impacts on soil organic carbon stocks in the Semiarid Chaco Region, Argentina.
Land use change affects soil organic carbon (SOC) and generates CO2emissions. Moreover, SOC depletion entails degradation of soil functions that support ecosystem services. Large areas covered by dry forests have been cleared in the Semiarid Chaco Region of Argentina for cropping expansion. However, deforestation impacts on the SOC stock and its distribution in the soil profile have been scarcely reported. We assessed these impacts based on the analysis of field data along a time-since-deforestation-for-cropping chronosequence, and remote sensing indices. Soil organic C was determined up to 100cm depth and physically fractionated into mineral associated organic carbon (MAOC) and particulate organic C (POC). Models describing vertical distribution of SOC were fitted. Total SOC, POC and MAOC stocks decreased markedly with increasing cropping age. Particulate organic C was the most sensitive fraction to cultivation. After 10yr of cropping SOC loss was around 30%, with greater POC loss (near 60%) and smaller MAOC loss (near 15%), at 0-30cm depth. Similar relative SOC losses were observed in deeper soil layers (30-60 and 60-100cm). Deforestation and subsequent cropping also modified SOC vertical distribution. Soil organic C loss was negatively associated with the proportion of maize in the rotation and total crop biomass inputs, but positively associated with the proportion of soybean in the rotation. Without effective land use polices, deforestation and agricultural expansion can lead to rapid soil degradation and reductions in the provision of important ecosystem services.
Unidad Integrada Balcarce, Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata (UNMdP) - Estación Experimental Agropecuaria Balcarce (INTA), Argentina; Consejo Nacional de Investigaciones Científicas (CONICET), Argentina. Electronic address: sebavillarino@gmail.com.
Sebastián Horacio
SH
Villarino
Unidad Integrada Balcarce, Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata (UNMdP) - Estación Experimental Agropecuaria Balcarce (INTA), Argentina.
Guillermo Alberto
GA
Studdert
LART - IFEVA, Facultad de Agronomía, Universidad de Buenos Aires, CONICET, Argentina.
Pablo
P
Baldassini
Unidad Integrada Balcarce, Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata (UNMdP) - Estación Experimental Agropecuaria Balcarce (INTA), Argentina.
María Gabriela
MG
Cendoya
LART - IFEVA, Facultad de Agronomía, Universidad de Buenos Aires, CONICET, Argentina.
Lucía
L
Ciuffoli
Unidad Integrada Balcarce, Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata (UNMdP) - Estación Experimental Agropecuaria Balcarce (INTA), Argentina; Consejo Nacional de Investigaciones Científicas (CONICET), Argentina.
Matias
M
Mastrángelo
Consejo Nacional de Investigaciones Científicas (CONICET), Argentina; LART - IFEVA, Facultad de Agronomía, Universidad de Buenos Aires, CONICET, Argentina.
Gervasio
G
Piñeiro
CO(2); Carbon dioxide emission; Dry forest; Land use change; Soil organic carbon; Soybean