Science et changements planétaires / Sécheresse


Stocks of organic carbon in the soils of the arid Coquimbo region (Chile): Consequences of goat grazing practices Volume 22, issue 4, Octobre-Novembre-Décembre 2011


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Universidad de Chile Facultad de Ciencias Agronómicas Departamento de Ciencias Ambientales y Recursos Naturales Renovables Avenida Santa Rosa #11315 882 08 08 - La Pintana Santiago de Chile Chili, Université d’Orléans UMR 6113 – CNRS Institut des sciences de la terre d’Orléans 1A, rue de la Férollerie 45071 Orleans cedex 2 France

The stocks of soil organic carbon were studied under moderate (6 SRU ha -1·year -1) and intensive goat grazing (10 SRU·ha -1·year -1) and compared with the stock present under native vegetation in the experimental station of Las Cardas (Coquimbo region, Chile). Results show that under moderate goat grazing (6 SRU ha -1·year -1), the organic carbon stock to 1m of depth would not be affected with 24.3 to 29.3 Mg·ha -1 compared to 31.1 to 42.6 Mg·ha -1 under native vegetation. These stocks are not significantly different ( P=0.95) and the differences can be attributed to the variability between replications. On the other hand, under intense goat grazing, the organic carbon stock was only 10.2 to 15.5 Mg·ha -1. Finally, our results show that it is possible to predict the stock of soil organic carbon by using the stock of soil organic carbon within the 0-30cm top layer alone (R 2=0.89) with a bias of <0.1 Mg·ha -1 and a precision of 3.6 Mg·ha -1.