| The Influence of Over-mature, Degraded Native Forests with Strong Anthropic Disturbance and Its Gradual Recovery with Silvopasture in Southwestern South America Francis Dube1; Marianela Alfaro2; Erick Zagal3; 1UNIVERSITY OF CONCEPCIóN, Concepción, Chile; 2UNIVERSIDAD DE COSTA RICA, San José, Costa Rica; 3UNIVERSITY OF CONCEPCIóN, Chillán, Chile; PAPER: 371/Ecosystems/Keynote (Oral) SCHEDULED: 16:45/Wed. 30 Nov. 2022/Arcadia 2 ABSTRACT: The increasing demand for timber and non-timber products from native forests in Chile and the cattle grazing has augmented the rate of degradation of these ecosystems. This process results in the need to know which of the dynamic variables are involved in its regulation. Soil quality indicators like soil organic carbon (SOC), soil microbial respiration (SMR), microbial biomass carbon (MBC), potential net N mineralization (N-min), and nitrification (N-NO), soil aggregates, and light fraction (LF), were evaluated at two different depths of the soil in Nothofagus obliqua (deciduous) and mixed N. dombeyi - N. obliqua (evergreen-deciduous) forests, where a 30-ha silvopastoral trial was established, after this evaluation, in early 2016 1. The SOC, SMR, MBC, N-min and N-NO were significantly higher in the N. obliqua forest than the mixed forest, 8%, 17%, 17%, 40%, 20%, respectively (p<0.05). The dry weight in soil fractions did not present differences between forest types. C and N contents in the LF (labile, un-decomposed organic matter of plant origin) were higher in the deciduous forest, 9% and 20%, respectively (p<0.05) 2. Our results suggest that soil quality was favored by the quality of organic matter in the site dominated by deciduous species, which translates into more favorable conditions for the activity of microorganisms, nitrogen dynamic, and C and N content in the light faction. The intrinsic characteristics of the plant residues associated with higher rates of decomposition, can stimulate the activity of the biota and especially the soil microorganisms, which would lead to higher values of the different indicators evaluated 3. This novel silvopastoral system will likely help restore the most degraded sites through improvement of the soil quality. This kind of information allows obtaining knowledge of forest areas and their sustainability, mainly for the planning of long-term, durable silvopastoral practices 4. References: 1 Dube, F., Stolpe, N.B., Zagal, E., Figueroa, C., Concha, C., Neira, P., Carrasco, C., Schwenke, J.M., Schwenke, V., Müller-Using, B. 2018. Novel Agroforestry Systems in Temperate Chile. In: Gordon, A.M., Newman, S.M. & Coleman, B.R.W. (Eds.). Temperate Agroforestry Systems, 2nd edition, CABI Publishing, United Kingdom, 326 pp. ISBN 9781780644851. 2 Alfaro, M., Dube, F., Zagal, E. 2021. The influence of over-mature, degraded Nothofagus forests with strong anthropic disturbance on the quality of an Andisol, and its gradual recovery with silvopasture in southwestern South America. In: Dagar, J.C., Gupta, S.R. & Teketay, D. (Eds.). Agroforestry for Degraded Landscapes: Recent Advances and Emerging Challenges, Vol. 2, Springer, Singapore, 475 pp. ISBN 978-981-15-6806-0. 3 Alfaro, M., Dube, F., Zagal, E. 2017. Soil quality indicators in an Andisol under different tree covers in disturbed Nothofagus forests. Chilean Journal of Agricultural Research, 78(1): 106-116. 4 Dube, F., Stolpe, N.B. 2016. SOM and biomass C stocks in degraded and undisturbed Andean and Coastal Nothofagus forests of southwestern South America. Forests. 7(320) |
