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Vegetal covers protect the soil against erosion in agricultural systems. In marginal olive farms, spontaneous grass covers are preferred due to their low cost, despite their high spatial and temporal heterogeneity which limits their efficiency. Although the impact of different managements, soil conditions or cover crops species has been evaluated and compared, there is currently insufficient information available on the spatial and temporal patterns of spontaneous grass covers in olive groves. This work focuses on the analysis of the spatial distribution patterns, temporal stability and protection capacity of spontaneous grass covers in olive orchards. First, the temporal variability of spontaneous grass cover was explored in relation to the meteorological conditions and the management system. Second, spatial analysis by distance indices (SADIE) was applied to explore the spatial patterns and persistence of the spontaneous cover. Finally, a descriptive analysis of events was made to illustrate the degree of influence of the cover on the hydrological response of the catchment. A total 12 surveys were carried out on a seasonal scale over 3 years (2011 − 2013) to measure the cover percentage of spontaneous grass through surface photograph analyses. A regular, permanent grid of 37 points (6 samples/ha) was used to define each sample-location. In order to evaluate the relations between the cover percentage and meteorological variables, multiple linear regressions were adjusted while the SADIE approach and correlation analysis were used to describe possible spatial aggregation patterns and its dependence on topographical and soil attributes such as aspect, slope, drainage area, height, richness of grass species and apparent electrical conductivity. The average annual percentage of cover ranged from 23% to 36%, with a coefficient of variation of 57% and 6%, respectively. On the seasonal scale, the cover varied between 0.2% and 50%. Accumulated precipitation during the precedent 15 days, the average of minimum temperature of the previous 60 days and the cumulated potential evapotranspiration of the same period showed a significant correlation with the mean cover percentage in the catchment. A simple multiple linear regression adjustment between the cumulated precipitation for the 15 previous days and the number of months since the vegetation was removed using herbicide or by summer conditions gave a determination coefficient of 77%. Moreover, a permanent spatial pattern was observed for periods characterized by abundant preceding rainfall. Only the apparent electrical conductivity of the topsoil (50 cm in depth) showed significant correlations with the spatial patterns of spontaneous grass. Finally, similar rainfall events taking place with different degrees of soil cover presented very different hydrological responses, which allowed us to quantify the contribution of spontaneous vegetation to sediment dynamics during humid periods. [ABSTRACT FROM AUTHOR]

To optimize soil conservation strategies in catchments, it is required an accurate diagnosis of the areas contributing to soil erosion by using models such as SEDD (Sediment Delivery Distributed model). In this study, different calibration strategies of the SEDD model were explored to adapt its use in two olive catchments with different environmental features and managements. A data series of rainfall–runoff–sediment load, collected in the catchments for 6 years was used: i) to evaluate calibration strategies for different management and flow conditions through the analysis of the C and R factors, and ii) to describe the temporal patterns of sediment delivery ratio ( SDR ) at the event and annual scales. Different results and calibration approaches were derived from contrasting soil features and sediment dynamics in the catchments. A good model performance with simple calibration procedure was obtained for the catchment with clayey soil and a very active gully, whereas the model parameterisation was adapted to event features in the catchment with sandy soil where the importance of concentrated flow was minor. Mean annual values of SDR at the watershed scale ( SDR w ) were 110.1% for the catchment with clayey soil and 64.1% for that with sandy soils. SDR w values greater than 100% occurred in very humid years with precipitations 30% above the mean annual values. At the event scale, similar behaviours of SDR were observed. SDR > 100% were associated with the gully exporting sediments out from the clayey catchment, whereas this was done by rills and an ephemeral gully in the sandy catchment. [ABSTRACT FROM AUTHOR]

Soil water repellency (SWR) has been reported under different soils, land uses and regions of the world, particularly in forest land and after wildfires, yet the understanding of this variable in agricultural lands is still rather limited. This study presents the characterization from field-based measurements of SWR in four contrasted olive groves ( Olea europaea L.) in Spain in terms of different environmental conditions and management: abandoned and commercial farms under permanent cover crop, conventional tillage and herbicide use. The main objectives were [1] to evaluate the potential occurrence, intensity and persistence of soil water repellency in different types of olive groves and [2] to explore its spatio-temporal features as well as the influence of soil properties such as organic matter (OM) and soil moisture. The Water Drop Penetration Time test (WDPT) was used in situ to assess SWR values. Measurements were carried out in two areas for each of the four groves: below and between the tree canopies. A high spatial and seasonal variability was observed. SWR was absent (WDPT = 0 s) for the olive groves under conventional tillage and with the lowest values of OM (OM-mean = 2.04%). The maximum WDPT values were found for cover crop under canopy in summer (WDPT-max = 610 s) and on the lanes in autumn (WDPT-max = 468 s). SWR was developed during the dry season, and to be reduced during the rainfall season as the organic compounds might be reoriented and turned amphiphilic. Strong water repellent values (> 60 s) were related with extremely high OM values (> 12%) for the cover crop orchard. [ABSTRACT FROM AUTHOR]

The curve number (CN) method is widely applied around the world to estimate direct runoff and the corresponding hydrograph of a rainfall event. However, there is no information on its performance in olive orchards on the catchment scale. In this work, the CN method was applied in three small catchments in southern Spain with different soil types, topography, and management. A rainfall-runoff data set of six years was used to test the usefulness of the method and the accuracy of its reference parameterization (CNs) and of the initial abstraction (Ia). CN medians in the catchments were between 83 and 87. Classical equations based on the use of the 10th, 50th, and 90th CN percentiles for determining the antecedent moisture content (AMC) provided very good results in two of the catchments. In the third catchment, with the most arid hydrological pattern (annual rainfall <400 mm) and the most impervious areas of parental material, very poor performance was achieved. In addition, cumulative precipitation was not a good indicator of AMC. Finally, significant deviations were observed in reference CNs for sandy soils that should be treated with caution for hydrological planning. They illustrate the need for new studies evaluating the hydrological behavior of olive orchard catchments with different environmental features and management practice. [ABSTRACT FROM AUTHOR]

Applying pruning residues in the lanes of olive groves has become a popular practice because it is economical and accrues benefits for soil and water management. This study presents an analysis of the impact of different rates of pruning residue on soil properties, in particular related with soil quality. Over 4 annual campaigns, chopped pruning residues used as a mulch were analyzed in terms of composition, coverage and moisture content to evaluate their effects on the amount of soil organic carbon (−10 cm and −20 cm) and CO 2 emissions, temperature and moisture. The experiment was carried out in a super-intensive olive orchard in Cordoba (SE, Spain) and used four amounts of fresh pruning residue: 7.5 t ha⁻1(T1), 15.0 t ha⁻1 (T2) and 30.0 t ha⁻1 (T3), with a control T0 = 0.0 t ha1. Mulch mean leaf fraction was 46.0 ± 17.5% (±SD) and initial water content, 24.8 ± 8.6%. The mulching benefits for soil moisture were observed in amounts of pruning residue >7.5 t ha⁻1, which are only produced in super-intensive olive groves or in orchards with high tree densities. The low impact of the treatments on soil moisture was explained by the dramatic annual variations in residue moisture contents, caused by the regimes of high temperatures and rainfall-evapotranspiration deficits inherent to the Mediterranean Basin climate. Thus, the mulching capacity only resulted efficient when the residues were still humid in spring. In addition, 15.0 t ha⁻1 of pruning residues was the threshold to provide significant increases in soil organic carbon at depths of 0–20 cm. Thus, accumulating pruning residue in lanes at rates of over 15 t ha⁻1 (T2 and T3) is more convenient than a uniform distribution with lower amounts, due to the low mineralization rates occurring during warm seasons and the larger inputs of OM increasing the annual balance of SOC. [Display omitted] • The impact of olive tree pruning residue rates on soil properties was studied. • The mulching benefits for soil moisture were observed with rates >7.5 t ha−1 • The residue mulching capacity on soil moisture only resulted efficient when fresh. • 15.0 t ha⁻1 of residues was the threshold to significant increases in topsoil SOC. • Accumulated residues in some lanes at rates >15 t ha⁻1 is the best management. [ABSTRACT FROM AUTHOR]

Student responsibility is demonstrated when students take an active role in their learning and take actions to face their educational goals. It is worth noting how inquiry learning in Sciences and Engineering provides suitable contexts in which students can build knowledge to solve problems, make decisions and find solutions to challenges in today's world (García-Medina and García Fernández, 2015; William and Otrel-Cass, 2017) In this work, we describe the practical experience of presenting the features and usefulness of innovative ICTs associated to the organisation of a workshop carried out by students of the Forest Engineering degree in the University of Cordoba (Spain).The workshop was conceived as a final work in the context of the subject "Computer tools in Forest Engineering Projects". The participation as a speaker in the workshop was a voluntary activity included in the teaching guide and was assigned with academic marks. Moreover, the participation as an author of the present contribution to the EGU Assembly 2019 was also another incentive to get involved in the activity. Firstly, teachers and students agreed on the content of the talk, which had to deal with innovative technological tools. Then, the programme of the workshop was announced on the Moodle platform. Each speaker had to explore a computer tool and prepare an English presentation with a a duration between 15 and 30 minutes. The pieces of software presented were "Genially" (https://www.genial.ly/es), "Classcraft" (https://www.classcraft.com/es/) and "Some useful Apps in Forest Engineering" In the closure, a coffee time was also scheduled in order to collect feedback about the experience in an informal way. In addition to the organisation of the workshop in terms of announcement and equipment, the teachers collected the presentations and the material prepared, recorded the session and edited a video which can be viewed on Moodle. Despite the lack of quantitative indicators about the experience, the presentations resulted excellent and the teachers observed how the students were empowered when they adopted the teaching role. It was also significant how the "camera effect" was useful to take the importance of English speaking seriously, as well as to improve student responsibility and collaborative competencies.REFERENCES:R. García-Medina, J.A.García-Fernández. 2015. Cooperar para enseñar, aprender cooperativamente REIRE: revista d'innovació i recerca en educació, Vol. 8(2), 230-241.P. J. Williams, K. Otrel-Cass. 2017. Teacher and student reflections on ICT-rich science inquiry. Research in Science & Technological Education. Vol. 358(1), 88-107. [ABSTRACT FROM AUTHOR]

1% of the world agricultural area is dedicated to olive groves. 48% of world olive oil is produced in Spain, on an area of 2,6 Mha of which, more than 60% is located in Andalusia, in the Southern region (Vilar and Pereira, 2017). Despite the economic, social and cultural relevance of olive grove in the Mediterranean Basin, some studies have highlighted the crop's susceptibility to land degradation and loss of biodiversity, in particular when climate change is considered. In this context, the analyses and monitoring of soil organic carbon (SOC) stock changes are crucial to identify risk of desertification and to fulfill environmental protection global conventions (FAO, 2018).In this work, a sensitivity analysis of the AnnAGNPS model (Bingner et al., 2018) to characterize the impact the different groups of input parameters under real scenarios of extensive olive groves in Andalusia (Spain) is going to be presented. The main aim is to evaluate and to compare the impact on carbon dynamics in an extensive olive orchard catchment where different soil types and managements were parameterized and contrasted with varying hydrological periods through AnnAGNPS simulations.Firstly, model parameters will be evaluated and grouped by soil categories, hydrological features, and management in order to quantify their impact on the sediment carbon loads at the event, monthly and annual scales. A total of 108 scenarios will be prepared in order to describe the influence of 6 soil types, 3 managements (no-till, conventional till and no till with spontaneous grass cover), 3 different rates of fertilization and 2 contrasted organic carbon life-time. On the other hand, the variations of ground carbon content will be also studied at the annual scale. A sensitivity analysis based on the Regression method (Song et al., 2015) will allow us to observe the most significant parameters and features as well as the suitability of the results when comparing bibliographical data. REFERENCESR. L. Bingner, F. Theurer, Y. Yuan, E.V. Taguas. 2018. AnnAGNPS TECHNICAL PROCESSES Documentation Version 5.5. USDA-ARS, National Sedimentation Laboratory, Oxford (MS, US). (https://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&H/AGNPS/downloads/AnnAGNPS%5fTechnical%5fDocumentation.pdf)FAO- Food and Agriculture Organization of the United Nations, 2019. Global Soil Partnership. Accessed at: January 2019. http://www.fao.org/global-soil-partnership/resources/highlights/detail/en/c/1109389/X. Song, J. Zhang, C. Zhan, Y. Xuan, M. Ye, X. Chonggang. 2015. Global sensitivity analysis in hydrological modeling: Review of concepts,methods, theoretical framework, and applications. Journal of Hydrology 523, 739-757.J. Vilar, J.E. Pereira. 2017. Informe de la Caja Rural de Jaén sobre coyuntura para la olivicultura internacional. Campaña 2016-2017. Conference Expoliva, Jaén, May 2017. Accessed at: January 2019. http://www.expoliva.info/archivos/informe%5fcaja%5frural.pdfACKNOWLEDGMENT: This study was supported by the project CGL2015-64284-C2-2-R (Spanish Ministry of Economy and Competitiveness). [ABSTRACT FROM AUTHOR]

Knowledge of spatio-temporal soil-water content (SWC) variability in agricultural fields is useful for improving crop management. Spatial patterns of SWC can be characterized using temporal stability analysis of difficult-to-obtain data from high spatial density and temporal frequency. Soil apparent electrical conductivity (ECa) measurements with high spatial density have been widely used to infer the spatial variability of SWC. The objective of this work is to test the hypothesis that temporal stability of ECa can be demonstrated and that relationships between temporal stability characteristics of SWC and ECa can be established. Apparent electrical conductivity and topsoil gravimetric SWC ( θ ) were periodically measured in an olive orchard in southwest Spain on 6 and 18 occasions, respectively. A temporal stability analysis of ECa elucidated three zones where ECa was close to, consistently substantially smaller than, and substantially larger than the spatial average ECa throughout the study period. Representative locations for θ were found with a chance of 75% within the representative zone for ECa. Yet, the driest locations, with consistently smaller θ than the field average ( 〈 θ 〉 ), could be successfully identified (89%) within the zone with consistently smaller ECa than average. The θ − 〈 θ 〉 relations showed generally a linear behaviour, although a better fit was obtained at the highest θ using either exponential or power law equations at half of the locations. The former provided the best fit within the zone with ECa consistently smaller than average, while the latter performed best in the zone with ECa consistently larger than average. The linear equation provided the best fit within the representative ECa zone. This study demonstrates that temporal stability characteristics of ECa and SWC are linked and that ECa surveys can be used to delimit zones with representative locations for SWC measurement or estimation. Such information is of importance for a range of agricultural applications, i.e . irrigation, crop protection, fertilizer management, and soil and water conservation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Integrated assessment model of degradation by water erosion in olive groves. [•] System dynamics approach to face the relative scarcity of data. [•] Calibration for four representative case studies in Andalusia (S Spain). [•] In cases, economic collapse occurs within 100years. [•] Annual economic losses due to soil erosion are small and go unnoticed by farmers. [Copyright &y& Elsevier]

Soil erosion is enhanced by wildfire, mainly due to the loss of vegetation cover and changes in soil properties. After wildfires, there is a need to control the non-sustainable soil and water losses. Of the strategies commonly applied, the use of contour felled log debris barriers to sediment trapping is widespread, but this is not always successful in Mediterranean Ecosystems. This paper evaluates the effectiveness of a new barrier which can be applied on steep terrains affected by wildfires. The hydrological response and sediment delivery were measured to test a innovative design, which are easy to transport and use. The Easy-Barriers (EB) size is 0.8 × 0.1 × 0.2 m and were designed to restore degraded areas which need a quick, low-cost solution, such as after a wildfire. The experimental design was based on the analysis of a simulated runoff flow of 0.6 l·s-1 circulated on 6 plots of 24 m2 (0.8 × 30 m), on each of which 2 treatments were systematically applied: Control and EB. The EB were set up after the assessment of the runoff generation and the site rainfall characteristics for "extraordinary" events. We measured the rills, the sediments collected on each slope and the topographical changes. The total load and runoff in the outlet of the plots were also quantified using sediment volume and concentration measurements. The EB resulted in a decrease in the peak flow and a delay in the runoff time at the outlet. The sediment trapping rate of the barriers was 42.7%. The soil moisture was higher in the EB plots due to the accumulated sediment. In addition to these features, the EB allow us to save between 30 and 40% of total restoration costs in comparison with traditional barriers, due to the reduction in labour costs. Moreover, all its components are biodegradable. Unlabelled Image • An Easy-to-Apply Barrier (EB) was designed and tested in the field. • The EB design and field layout were based on the environmental site features. • Runoff simulations experiments showed EB benefits for extreme events >10 y-return period. • EB reduced soil losses and runoff peaks, and increased soil moisture. • EB could be used to restore degraded areas and labour costs associated to its use are lower than with other barriers. [ABSTRACT FROM AUTHOR]

The use of cover crops has been prescribed as a mitigation measure for offsite contamination, as they reduce sediment and agrochemical loads, thus reducing the hydrological connectivity of the land. However, there is the need to quantify its effectiveness for specific agrochemicals in broader range of conditions, to validate management for its safe environmental use. The objectives of the present study were: (1) to explore the use of simulated rainfall and magnetic iron oxide to understand the impact of vegetation strips on runoff and soil losses at the plot scale and, (2) to evaluate the effectiveness of vegetation strips in buffering sediment and herbicides coming from bare soil areas. The study encompasses six sets of rainfall simulations (three replications each) under four different soil management scenarios: dry vegetation cover sowed that year, dry vegetation cover two years after sowing, freshly-tilled soil, and tilled soil with a compacted surface due to rainfall and trampling. The experiments involved the use of a magnetic iron oxide as a sediment tracer to obtain a better understanding of the trapping efficiency of the vegetation strips. Three runoff plots were established on a hillslope under a Fluvisol alluvial terrace. Each of the plots contained three bare areas tagged with magnetic iron oxide and three strips with Lolium multiflorum L. The results indicate that by using cover crop strips, runoff and sediment losses were approximately 20% and 4%, respectively, of the losses measured in the bare compacted soil, while losses on the freshly-tilled surface were similar to that of the cover crop. Herbicide losses were greatly reduced by the cover crops, with losses ranging from approximately 0.1%–0.6% of the doses applied the day before on the bare area. Nevertheless, on the compacted bare soil, terbuthylazine, oxyfluorfen and diflufenican losses were 1.63%, 4.35% and 9.67%, respectively, of the dose applied the previous day. This can be explained because the tilled and compacted soil showed the highest cumulative runoff and soil losses values (28 mm and 248.9 g m −2 ). The formation of micro-relief steps after the first simulation reduced the hillslope connectivity and, thus, the soil losses and runoff. Tracer selectivity from soil textures with fine particle size (clay) was observed, as there was an enrichment of these particles in the collected sediment. This study quantified the impact of cover crop strips on mitigating offsite herbicide contamination and improved our understanding of sediment redistribution at the hillslope scale. [ABSTRACT FROM AUTHOR]

This paper presents a virtual lab for the contents of an Engineering project, for designing an agro-industrial building, which is also useful for a range of different transversal courses in Engineering sciences. The aims of this tool are to analyse the most important contents of a project-document (calculation, regulations, drawings and budgets), as well as their relationship with the activities which make up the work and the schedule. The design criteria we considered were: its online applications and their compatibility with Moodle; the inclusion of different learning approaches, such as exploratory learning and inquiry-based learning; its interactivity, and the use of multimedia elements for visualisation and direct analysis on material common to Engineering subjects. The students’ perceptions of the improvements brought by the virtual lab were analysed statistically through a series of questions over two academic years. The results of the questionnaires suggested that most of those who had used the e-learning tool valued positively its overall suitability for reaching the objectives in their subject as well as the way it improved the working methodology. The practical knowledge acquired by the students was also highly valued. In addition, the lack of constraints commonly related to field trips (expenses, time and complexity) illustrates the utility of self-access learning tools in key transversal disciplines such as Engineering projects. [ABSTRACT FROM PUBLISHER]

Highlights: [•] The study characterises hydrologic and erosive response in an orchard on a Vertic soil. [•] It indicates the major variables controlling the hydrologic and erosive response. [•] It shows unsustainable soil losses in an olive orchard fulfilling CAP requirements. [•] There is a need for more effective erosion control measures under these conditions. [ABSTRACT FROM AUTHOR]