• Rural Digital Europe
• DIGITAL.CSIC close

High values of pH may represent a limitation for the agricultural use of the composts, not only when used as soil-less substrate but also as soil amendment in high pH soils. The addition of elemental S during the maturation phase of the composting process was evaluated as suitable method to reduce pH of the composts under the organic agriculture regulations. A compost prepared with two phase olive mill waste (OMW) and sheep litter (SL) was used to study the effect of elemental sulphur addition on the pH of the composting mixture. Initially, different bench scale experiments were designed in order to study the influence of moisture, sulphur concentration, and incubation temperature on the sulphur oxidation rate and thus on the pH of the compost. A concentration of 0.5% in sulphur (dry weight basis) and moisture of 40% were proposed as the optimum conditions to decrease the compost pH by 1.1 units without increasing in EC to levels that may suppose a limitation for its agricultural use. Finally, these optimum experimental conditions found at bench scale were tested at full scale in a commercial composting plant treating the same organic materials by windrowing. The pH values of the composting mixture were reduced by one unit after 2 weeks following the addition of elemental S causing no negative effects on the final compost quality. The authors wish to thank the Spanish Comisión Interministerial de Ciencia y Tecnología (CICYT) for supporting the research project Ref.PTR1995-0458-OP under which this work was financed. 7 pages, 4 tables, 5 figures. Peer reviewed

The high impact of irrigation in crop quality and yield in grapevine makes the development of plant water status monitoring systems an essential issue in the context of sustainable viticulture. This study presents an on-the-go approach for the estimation of vineyard water status using thermal imaging and machine learning. The experiments were conducted during seven different weeks from July to September in season 2016. A thermal camera was embedded on an all-terrain vehicle moving at 5 km/h to take on-the-go thermal images of the vineyard canopy at 1.2 m of distance and 1.0 m from the ground. The two sides of the canopy were measured for the development of side-specific and global models. Stem water potential was acquired and used as reference method. Additionally, reference temperatures T and T were determined for the calculation of two thermal indices: the crop water stress index (CWSI) and the Jones index (I). Prediction models were built with and without considering the reference temperatures as input of the training algorithms. When using the reference temperatures, the best models casted determination coefficients R of 0.61 and 0.58 for cross validation and prediction (RMSE values of 0.190 MPa and 0.204 MPa), respectively. Nevertheless, when the reference temperatures were not considered in the training of the models, their performance statistics responded in the same way, returning R values up to 0.62 and 0.65 for cross validation and prediction (RMSE values of 0.190 MPa and 0.184 MPa), respectively. The outcomes provided by the machine learning algorithms support the use of thermal imaging for fast, reliable estimation of a vineyard water status, even suppressing the necessity of supervised acquisition of reference temperatures. The new developed on-the-go method can be very useful in the grape and wine industry for assessing and mapping vineyard water status. This work is part of the RESOLVE project, for which the authors acknowledge the financial support provided by transnational funding bodies, being partners of the FP7 ERA-net project, CORE Organic Plus, and the cofund from the European Commission. Salvador Gutierrrez would like to acknowledge the research founding FPI grant 299/2016 by Universidad de La Rioja, Gobierno de La Rioja. Dr. Maria P. Diago is funded by the Spanish Ministry of Economy, Industry and Competitiveness (MINECO) with a Ramon y Cajal grant RYC-2015-18429. Peer reviewed

Photosynthesis is essential for life on earth as it, inter alia, influences the composition of the atmosphere and is the driving mechanism of primary production. Photosynthesis is particularly controlled by leaf pigments such as chlorophyll, carotenoids or anthocyanins. Incoming solar radiation is mainly captured by chlorophyll, whereas plant organs are also protected from excess radiation by carotenoids and anthocyanins. Current and upcoming optical earth observation sensors are sensitive to these radiative processes and thus feature a high potential for mapping the spatial and temporal variation of these photosynthetic pigments. In the context of remote sensing, leaf pigments are either quantified as leaf area-based content [μg/cm2] or as leaf mass-based concentration [g/g or %]. However, these two metrics are fundamentally different, and until now there has been neither an in-depth discussion nor a consensus on which metric to choose. This is notable considering the amount of studies that do not explicitly differentiate between pigment content and concentration. We therefore seek to outline the differences between both metrics and thus show that the remote sensing of leaf pigment concentration [%] is unsubstantial. This is due to the fact that, firstly, pigment concentration is likely to primarily reflect variation in leaf mass per area and not pigments itself. Second, the radiative transfer in plant leaves is especially determined by the absolute content of pigments in a leaf and not its relative concentration to other leaf constituents. And third, as a ratio, pigment concentration is an ambiguous metric, which further complicates the quantification of leaf pigments at the canopy scale. Given these issues related to the use of chlorophyll concentration, we thus conclude that remote sensing of leaf pigments should be primarily performed on an area basis [μg/cm2]. The project was funded by the German Aerospace Center (DLR) on behalf of the Federal Ministry of Economics and Technology (BMWi), FKZ50EE 1347. Peer reviewed

Within the Subantarctic Mode Water (SAMW) density level, we study temporal changes in salinity, nutrients, oxygen and TTD (Transit Time Distribution) ages in the western (W) and eastern (E) subtropical gyre of the Indian Ocean (IO) from 1987 to 2002. Additionally, changes in Total Alkalinity (TA) and Dissolved Inorganic Carbon (DIC) are evaluated between 1995 and 2002. The mechanisms behind the detected changes are discussed along with the results from a hindcast model run (Community Climate System Model). The increasing salinity and decreasing oxygen trends from 1960 to 1987 reversed from 1987 to 2002 along the gyre. In the W-IO a decreasing trend in TTD ages points to a faster delivery of SAMW, thus less biogenic matter remineralization, explaining the oxygen increase and noisier nutrients decrease. In the E-IO SAMW, no change in TTD ages was detected, therefore the trends in oxygen and inorganic nutrients relate to changes in the Antarctic Surface Water transported into the E-IO SAMW formation area. In the W-IO between 1995 and 2002, the DIC increase is equal or even less than the anthropogenic input as the reduction in remineralization contributes to mask the increasing trend. In the E-IO between 1995 and 2002, DIC decreases slightly despite the increase in the anthropogenic input. Differences in the preformed E-IO SAMW conditions would explain this behavior. Trends in the W and E IO SAMW are decoupled and related to different forcing mechanisms in the two main sites of SAMW formation in the IO, at 40°S–70°E and 45°S–90°E, respectively. 3

The article aims to analyze, based on a multiple case study, the discourses of the individuals that promote social innovation (SI) initiatives for the reuse of abandoned riverside landscapes, connecting SI theory with land reutilization and management through discourse analysis. Following a qualitative methodology, the text analyses the characteristics of the promoting actors, the discourses storylines and the main actors’ discourses, describing some relevant aspects regarding SI, such as why, where and when it takes place; how it has been developed; who has promoted it; its main results, as well as the barriers faced for its development and future opportunities for the territory. Two main discursive tendencies are identified: a negationist trend and a possibilistic one, adopted by individuals who are not promoting initiatives of SI and by promoters of these kinds of experiences, respectively. Possibilistic discourse underlines the coherent articulation between the economic-managerial dimension and the emotional-territorial one, and there is, in this case, a tendency to change in the visions of the territory, reconfiguring the social practices of the actors involved in these initiatives of SI. We conclude that discourses behind successful processes of SI are associated with certain positions on the interrelationships between individual- collective-institutionality-nature and that there is a complex articulation between discourses on SI and social practices developed by individuals as part of these initiatives, in such a reflexive way that discourses advance the desired changes, drawing and modifying the future vision of the subjects, and making the impossible possible. 19 Pags.- 4 figs.- 3 Tabls. © 2022 Sanz-Hernández, Jiménez-Caballero, Bacallao-Pino, Salvador Esteban and Martín-Santafé. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). This article is part of the Research Topic "Global Change in Forests and Their Communities: Analyzing Spatio-Temporal Changes in Forest Complex Socio-Ecological Systems". This research has been made possible thanks to the collaboration with the research team responsible for the “RegATeA Project” (https://regatea.cita-aragon.es), funding by regional government (Government of Aragon, through Teruel Investment Fund) (Fund of Investments of Teruel, 2019, 2020, and 2021), and national government (Territorial Policy Ministry, Spanish Government). Peer reviewed

Studying intra-annual growth dynamics through a modelling approach has proved useful for characterizing differences in wood phenology between species and deviations from the expected tree growth due to climate change. The aim of this paper was to determine the climatic factors and the inter- and intra-specific competition traits that drive intra-annual secondary growth dynamics in three Mediterranean tree species that naturally co-exist in the Spanish Northern Plateau (Pinus pinea L., Juniperus thurifera L., and Quercus ilex subsp. ballota (Desf.) Samp.). For this purpose, we obtained girth increment data from band dendrometers installed on 58 trees from May 2012 to April 2015. Half of them were located in a high-density plot and half were in a low-density plot. These data were analysed through a nonlinear multifactorial model considering daily and cumulative climatic effects together with inter- and intra-specific competition indices. Our results provide evidence of a spatiotemporal niche separation between species. Compared with other species, Q. ilex subsp. ballota showed a wider thermal amplitude, a higher mean optimum temperature for growth, and a milder effect of drought on its secondary growth. Under current climate change projections, simulations based on our model predict a secondary growth reduction for P. pinea and a growth enhancement for Q. ilex subsp. ballota in these Mediterranean mixtures.

Climate change and exotic pests and pathogens are causing alarming forest declines worldwide. However, we still lack a comprehensive understanding of how damage caused by exotic pests and pathogens might vary under the different scenarios of water availability imposed by a changing climate, particularly in water-limited forests as those that occupy Mediterranean areas. In this paper we aimed to experimentally analyse the interactive effects of the aggressive exotic pathogen Phytophthora cinnamomi and climate change-related reductions in soil moisture on seedling performance of the Mediterranean host Quercus suber. We conducted a full-factorial greenhouse experiment where the physiology and growth of Q. suber seedlings was measured in soils with different combinations of P. cinnamomi inoculum density (0, 30, 60 and 120 colony forming units per gram of dry soil) and soil moisture (15%, 40%, 50% and 100% soil water holding capacity) simulating different invasion and climate change scenarios. We found additive effects of P. cinnamomi and drought on Q. suber performance aboveground, although these effects were not always negative. In fact, seedlings showed a compensatory physiological response to P. cinnamomi infection by increasing their net photosynthetic rates. Our results also supported important interactive effects of pathogens and soil moisture on belowground performance. Thus, the inoculum density in the soil required to cause significant root damage in experimental seedlings decreased as soil moisture increased. From a climate change perspective, these results suggest that an average drier climate might imply sub-optimal conditions for P. cinnamomi infections allowing for a slower advance of the disease in invaded areas. However, this effect will be modulated by the also predicted more frequent extreme climatic events. A higher frequency of extreme rain events that saturate the soil might be particularly beneficial for P. cinnamomi, boosting its soil density beyond any possible response capacity of susceptible hosts. © 2019 This study was funded by the MICINN project INTERCAPA ( CGL2014-56739-R ). P.H. was supported by a FPI-MICINN grant, L.M. by an “Acción 6 UJA” fellowship (EI_RNM4_2017), O.G. by a Marie Sklodowska-Curie grant agreement ( No 661118-BioFUNC ), and I.M.P.R by a “Ramón & Cajal” contract ( RYC-2013-13937 ). 8 páginas.- 5 figuras.- 2 tablas.- 60 referencias Peer reviewed