Spontaneous grass covers are an inexpensive soil erosion control measure in olive orchards. Olive farmers allow grass to grow on sloping terrain to comply with the basic environmental standards derived from the Common Agricultural Policy (CAP, European Commission). However, to date there are few studies assessing the environmental quality considering such covers. In this study, we measured biodiversity indices for spontaneous grass cover in two olive orchards with contrasting site conditions and management regimes in order to evaluate the potential for biodiversity metrics to serve as an indicator of soil degradation. In addition, the differences and temporal variability of biodiversity indicators and their relationships with environmental factors such as soil type and properties, precipitation, topography and soil management were analysed. Different grass cover biodiversity indices were evaluated in two olive orchard catchments under conventional tillage and no tillage with grass cover, during 3 hydrological years (2011–2013). Seasonal samples of vegetal material and photographs in a permanent grid (4 samples ha−1) were taken to characterize the temporal variations of the number of species, frequency of life forms, diversity and modified Shannon and Pielou indices. Sorensen's index showed strong differences in species composition for the grass covers in the two olive orchard catchments, which are probably linked to the different site conditions. The catchment (CN) with the best site conditions (deeper soil and higher precipitation) and most intense management presented the highest biodiversity indices as well as the highest soil losses (over 10 t ha−1). In absolute terms, the diversity indices of vegetation were reasonably high for agricultural systems in both catchments, despite the fact that management activities usually severely limit the landscape and the variety of species. Finally, a significantly higher content of organic matter in the first 10 cm of soil was found in the catchment with worse site conditions in terms of water deficit, average annual soil losses of 2 t ha−1 and the least intense management. Therefore, the biodiversity indices considered in this study to evaluate spontaneous grass cover were not found to be suitable for describing the soil degradation in the study catchments.

The adoption of green roofs is an effective practice for mitigating environmental issues in urban areas caused by extreme weather conditions. However, certain design aspects of green roofs, such as the characterization of the physical properties of their substrates, need a better understanding. This study proposes a simple method for estimating two hydraulic properties of green roof substrates based on the evolution of moisture during drying periods, or drydowns, where evaporative processes dominate: the weighted-mean diffusivity and the saturated hydraulic conductivity. Soil moisture was monitored using 12 in situ sensors from 2015 to 2020 in a study involving six different green roof plots composed of various mixtures of demolition-recycled aggregates and organic substrates. A universal parameterization for determining water diffusivity in soils was applied to estimate the weighted-mean hydraulic diffusivity. As a by-product, the saturated hydraulic conductivity was estimated from the evaluated diffusivity and the measured water retention data. The median values obtained for $\overline{D}$ and $k_s$ range from 14.5 to 29.9 cm²d⁻¹ and from 22 to 361 cmd⁻¹, respectively. These values fall within the ranges reported by other research groups using direct measurement methods and supports the validity of Brutsaert’s model for green roof substrates. Furthermore, an increase in $\overline{D}$ and a decrease in $k_s$ were observed as the percentage of recycled aggregates in the substrates increased, which could be considered for design purposes.

Los corredores verdes urbanos son una solución basada en la naturaleza (SBN) que provee zonas de esparcimiento y una red de conectividad urbana para movilidad activa, además de prestar servicios ecosistémicos a los habitantes de las ciudades, que mejoran su calidad de vida, y son una herramienta de gestión fuerte para el desarrollo de ciudades sostenibles. El presente trabajo propone una novedosa metodología, susceptible de ser ampliada, para el diseño de corredores verdes urbanos, mediante un caso práctico en una ciudad de tamaño intermedio, Temuco (Chile), basada en la selección de áreas verdes urbanas pequeño-medianas que unidas a redes de ciclovías y calles peatonales conecten las áreas verdes núcleo de la ciudad, entendiendo estas como zonas verdes de alta densidad y diversidad vegetacional. Los resultados muestran la aplicabilidad de los criterios metodológicos utilizados en el diseño de corredores verdes, y evidencian las condiciones positivas de Temuco respecto a calidad y superficie de áreas verdes, ciclovías y calles peatonales que fomenten la movilidad urbana limpia. Además, el método es replicable en otras ciudades, lo que permite incorporar nuevos parámetros que supongan mayores beneficios provenientes del corredor verde.

Agricultural intensification has used technological advances to raise food production, but it has also created environmental imbalances. Environmental degradation, e.g. soil loss and offsite contamination, and loss of biodiversity, related to the expansion and intensification of agriculture, have been documented internationally[1][2]. Since the 1980s, with the Single European Act[3] as a legal basis, different attempts have been made to address this threat at European level through better focused environmental policies. For instance since the CAP reform in 1992, environmental sustainability of agriculture has been constantly ongoing. In fact, the latest reform post-2021 shows more ambitious objectives with the introduction of eco-regimes. Other key initiatives like the Green Infrastructure Strategies and the EU Mission: A Soil Deal for Europe have emerged[4][5][6] being focused on recovering natural capital as a source of ecosystem services.In this context, ALIve[7], SCALE[8] and ECOMED[9] projects and the Rural Landscape Diversification Program of the Córdoba Countryside[10] aim to provide scientific and technical knowledge for the sustainable intensification of agriculture in Mediterranean areas, in particular southern Spain, through nature-based solutions.Although vegetative barriers are one of the key instruments to manage agricultural landscapes towards sustainable intensification, detailed empirical information on how to implement them still scarce. This communication presents an experiment on different alternatives on how to stablish a vegetative barrier combining fifty-two herbaceous and woody species adapted for Mediterranean conditions. This experiment explores seventeen different strategies, combining different irrigation, mulching and tillage combinations. In these plots, growth, survival and phytosanitary status of the plants, and soil moisture at the end of each hydrological year were monitored since its implantation in February 2021. This communication presents results from the first year of implementation, as well as a costs analysis of the different strategies evaluated. This information can be valuable for practitioners and planners interested in these nature-based solutions.After the first year, it was observed that all the treatments presented a remarkable survival rate, above 48% (CoT4), albeit this increases with better management reaching 100% with better tillage, mulching and drip irrigation. Plant growth also responded to best management ranging from 14.1 cm in height (CoT4) and 11.8 cm in diameter (CoT3) to 46.7 cm in height (CoT9) and 58.8 cm in diameter (CoT9). The cost of implementation ranged from 1.7 €/m2 (CoT4) to 6.0 €/m2 (CoT9). Among the most successful individual operations is mulching with a fabric film, which despite having the highest implementation cost 2.5 €/m2 results in the lowest maintenance cost 0.4 €/m2.Acknowledgements: ALIve (PID2019-105793RB-I00), SCALE (Nº 862695) and ECOMED (PR.AVA23.INV202301.035).References:[1] MITECO, «Plan estratégico estatal del patrimonio natural y de la biodiversidad a 2030». 2022.[2] European Commission, «EU Biodiversity Strategy for 2030». 2020.[3] European Economic Community, «Single European Act». 1987.[4] European Commission, «Green Infrastructure (GI) — Enhancing Europe’s Natural Capital». 2013.[5] MITECO, «Estrategia Nacional de Infraestructura Verde y de la Conectividad y Restauración Ecológicas». 2021.[6] European Commission, «EU Mission: A Soil Deal for Europe». 2023.[7] https://alive.csic.es/[8] https://ejpsoil.eu/soil-research/scale/[9] https://www.juntadeandalucia.es/agriculturaypesca/ifapa/web/node/60947[10] https://www.jardinbotanicodecordoba.com/investigacion/diversificacion-del-paisaje-agrario/

Spontaneous grass covers are an inexpensive soil erosion control measure in olive orchards. Olive farmers allow grass to grow on sloping terrain to comply with the basic environmental standards derived from the Common Agricultural Policy (CAP). However, to date there are very few studies assessing the environmental quality and extent of such covers. In this study, we described and compared the biodiversity indicators associated to herbaceous vegetation in two contrasting olive orchards in order to evaluate its relevance and quality. In addition, biodiversity patterns and their relationships with environmental factors such as soil type and properties, precipitation, topography and soil management were analyzed. Different grass cover biodiversity indices were evaluated in two olive orchard catchments under conventional tillage and no tillage with grass cover, during 3 hydrological years (2011–2013). Seasonal samples of vegetal material and pictures in a permanent grid (4 samples ha−1) were taken to characterize the temporal variations of the number of species, frequency, diversity and transformed Shannon's and Pielou's indices. Sorensen's index obtained in the two olive orchard catchments showed notable differences in composition, probably linked with the different site conditions. The catchment with the best site conditions (deeper soil and higher precipitation), with average annual soil losses over 10 t ha−1 and a more intense management, presented the highest biodiversity indices. In absolute terms, the diversity indices were reasonably high in both catchments, despite the fact that agricultural activity usually severely limits the landscape and the variety of species. Finally, a significantly higher content of organic matter in the first 10 cm of soil was found in the catchment with the worst site conditions, average annual soil losses of 2 t ha−1 and the least intense management. Therefore, the biodiversity indicators associated to weeds were not found to be suitable for describing the soil degradation in the study catchments.