BALANCE Y HUELLA DE CARBONO EN OLIVARES ANDALUCES BAJO DISTINTAS PRÁCTICAS DE MANEJO

Las actividades agrícolas contribuyen a la emisión de gases de efecto invernadero a la atmósfera. El olivar es el cultivo leñoso más ampliamente distribuido en el mundo, con gran repercusión socioeconómica, cultural y ambiental de muchos pueblos de Andalucía. Por lo tanto, cualquier cambio en las prácticas de manejo tendrán una gran repercusión en la mitigación y adaptación al cambio climático, la biodiversidad y en la provisión de servicios ecosistémicos. Si además de considerar las emisiones de CO2 eq producidas en las labores de campo en la huella de carbono, se incluye el carbono biogénico, el olivar andaluz es sumidero neto de CO2, especialmente en aquellos olivares que implementen prácticas de manejo que incidan en el almacenamiento de carbono en el suelo y en la biomasa, lo que es esencial ante un sistema voluntario de monetización de los créditos de carbono.Agricultural activities contribute to the emission of greenhouse gases into the atmosphere. The olive grove is the most widely distributed woody crop in the world, with great socioeconomic, cultural and environmental repercussions in many Andalusian towns. Therefore, any change in management practices will have a great impact on mitigation and adaptation to climate change, biodiversity and the provision of ecosystem services. If, in addition to considering the CO2 eq emissions produced in the field work in the carbon footprint, biogenic carbon is included, the Andalusian olive grove is a net CO2 sink, especially in those olive groves that implement management practices that affect storage of carbon in the soil and in the biomass, which is essential before a voluntary system of monetization of carbon credits.Tesis Univ. Jaén. Departamento de Biología Animal, Biología Vegetal y Ecologí

Role of Clay Mineralogy in the Stabilization of Soil Organic Carbon in Olive Groves under Contrasted Soil Management

Cropland soils are key systems in global carbon budgets due to their high carbon-sequestration potential. It is widely accepted that clays are one of the soil components that have a significant effect on the stabilisation of soil organic carbon (SOC), owing to its surface interactions with organic molecules. However, the identification of the direct effects of clays on SOC stabilization is complicated, mainly due to the difficulty of accurately characterizing the mineralogy of clays, especially phyllosilicates. In this study, the relationships between soil phyllosilicates and functional SOC pools in woodlands and comparable olive groves, under two contrasting management systems (bare soils versus soil under cover crops) and parent materials (calcareous and siliceous), were explored. The total mineralogy of soil and clay fractions and the soil-clay assemblages were analysed through the decomposition of X-ray diffraction patterns, and were then related to four SOC pools. Total and unprotected SOC was higher in olive groves under cover crops, and this was true independent of the parent material, proving the importance of herbaceous covers in SOC sequestration in woody crops. Some significant correlations between clay minerals and SOC fractions were found. Interestingly, mixed-layer content was correlated with the biochemically protected SOC fraction (r = 0.810, p r = 0.761, p fdr < 0.25. The PCNs supported the direct correlation between mixed-layer content, especially those rich in smectite, and the biochemically protected SOC fraction, suggesting that smectite layers may stabilize organic molecules. Since potassium enrichment is higher in the rooted layers of woodland and soils under cover crops, and this increase is related to the collapse of swelling layers, these soils were poorer in smectite phases than the bare soils. This also would explain why the biochemically protected SOC was more abundant in the latter