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The Mediterranean region is facing major challenges for soil conservation and sustainable agriculture. Conservation agriculture (CA), including reduced soil disturbance, can help conserve soils and improve soil fertility, but its adoption in the Mediterranean region is limited. Examining farmers' perceptions of soil and underlying sociocultural factors can help shed light on adoption of soil management practices. In this paper, we conducted a survey with 590 farmers across Morocco, Spain and Tunisia to explore concepts that are cognitively associated with soil and perceptions of tillage. We also evaluated differences in perceptions of innovation, community, adaptive capacity, and responsibility for soil. We found that farmers' cognitive associations with soil show awareness of soil as a living resource, go beyond agriculture and livelihoods to reveal cultural ties, and link to multiple levels of human needs. Beliefs about the benefits of tillage for water availability and yield persist among the surveyed farmers. We found that openness towards innovation, perceived adaptive capacity and responsibility for soil were associated with minimum tillage, whereas community integration was not. Education, age and farm lifestyle were also associated with differences in these perceptions. CA promotion in the Mediterranean should emphasize the multiple values of soil, should demonstrate how sufficient yields may be achieved alongside resilience to drought, and be tailored to differing levels of environmental awareness and economic needs across north and south. [ABSTRACT FROM AUTHOR]

Land use plays a crucial role in the stock of soil organic carbon (SOC) and soil nitrogen (SN). The aim of this study was to assess and characterize the effects of various soil management practices on the physicochemical properties of soil in a Mediterranean region in southeastern Spain. Texture, soil moisture, bulk density, pH, electrical conductivity, equivalent CaCO3 (%), soil organic matter and carbon, and Kjeldahl nitrogen were determined for the surface topsoil (0–5 cm, 180 samples) under three types of land cover: cropland, grassland, and urban soil. The main soil textures were silt, silt loam, and sandy loam with low percentages of soil moisture in all soil samples and lower bulk density values in cropland and grassland areas. The pH was alkaline and the electrical conductivity as well as the equivalent calcium carbonate content were moderate to high. Organic matter estimated using the LOI and WB methods varied in the order cropland > grassland > urban soil. The results obtained for SOC and SN indicate that cropland presented the highest stocks, followed by grassland and urban soil. The values determined for the C/N ratio were close to 10 in cropland and grassland, indicating that organic matter readily undergoes decomposition at these sites. Our results emphasize the importance of evaluating the effects and identifying the impacts of different soil management techniques, and further research is needed to better understand the potential to improve soil organic carbon and nitrogen storage in semiarid regions. [ABSTRACT FROM AUTHOR]

The olive groves' relevance has historically been ingrained in Mediterranean cultures. Spain stands out as a leading producer worldwide, where olive trees are extensively grown in the Andalusian region. However, despite the importance of this strategic agricultural sector, cultivation through the years has given rise to various crop management practices that have led to disruptive erosion processes. The objective is to measure land erosion in over 100-year-old olive groves considering the 3D reconstructed recent relief of olive tree mounds. A time-of-flight depth sensor, namely, Kinect v2, was employed to 3D model the target areas, i.e., trunk and exposed roots, to determine the height as a surrogate of the difference between the historical and recent relief. In three plots in southern Spain, the height of relic tree mounds was measured in olive trees at the upper and bottom parts to determine soil profile truncation. The results were compared and validated with manual measurements (ground truth values). Olive trees were grouped into high, moderate, and low slope gradient classes. The results showed, in all cases, high consistency in the correlation equations (Pearson's coefficients over 0.95) between the estimated values in the models and the actual values measured in the olive trees. Consequently, these excellent results indicate the potential of this low-budget system for the study of historical erosion. Notably, the Kinect v2 can generate 3D reconstructions of tree mounds at microtopographic scales in outdoor situations that would be challenging for other depth cameras under variable lighting conditions, as found outdoors. [ABSTRACT FROM AUTHOR]

The effects of the farming system (conventional-organic-abandoned) and soil management (native cover crop vs tillage) on vascular plant species were analyzed in sloping olive groves (>20%) in 20 different locations in Andalusia, SE Spain. The soil management techniques included Organic Tillage (OT), Organic Cover Crops (OC), Conventional Tillage (CT), Conventional Non-Tillage (CNT), Abandoned Cover Crops (AC) and Abandoned Woody (AW). Data for the vascular plant species were recorded through three line transects of 30 m with a bar perpendicularly touching every 1m of the measuring tape. Environmental variables were also recorded at plot level to assess their influence. Dependent variables, such as species abundance, richness and diversity indexes were studied using univariate analysis (one-way ANOVA, Kruskal-Wallis test) while multivariate statistics (ANOSIM, SIMPER, DCA) were used for analyzing the data matrices. We found that the different combinations of farming system and soil management affect biological diversity in terms of individual abundance, plant cover, species richness and diversity, species and family composition. Life forms and species distribution patterns are also affected. The main environmental variables affecting the plant taxa were those related with soil and climate characteristics, slope, olive age and intensive land uses at landscape level, including the percentage of artificial surfaces. The lowest levels of biodiversity (e.g., species richness) were found in the tilled olive groves (CT = 8.1 sp. ± 2.2, OT = 10.0 sp. ± 5.4). Surprisingly, the organic tilled groves (OT) were very poor in species compared to those with native plant cover (OC = 27.9 sp. ± 3.0). The latter, however, showed similar species richness to the abandoned olive groves (AC = 21.2 sp. ± 3.7, AW= 27.2 sp. ± 3.0). Possible solutions for increasingly uncompetitive sloping olive groves include conversion to organic with native plant cover or abandonment for rewilding. [ABSTRACT FROM AUTHOR]

Background: Mulching and burnt wood treatments are commonly applied to prevent the loss of soil quality and erosion, but their effect on soil multifunctionality remains unexplored. Aims: We filled this gap by assessing the medium-term (4 years) effects of these treatments on soil multifunctionality after a large wildfire in NW Spain. Methods: Straw mulching (SM) and cut plus lopping (CpL) treatments were applied in high-severity affected areas of heathland plant communities. CpL areas had been afforested with Scots pine 15 years before the fire. We considered four soil functions estimated in treated and burned control plots 4 years after fire: (1) carbon regulation; (2) water regulation; (3) soil fertility; and (4) nutrient cycling. The functions were integrated into a multifunctionality index and linear models were used to evaluate treatments effect. Key results: SM had no impact on individual functions and multifunctionality. Conversely, CpL with burnt Scots pine wood was able to sustain higher levels of multiple functions simultaneously than control areas. Consistent trade-offs between soil functions emerged in control areas for both treatments. Conclusions: Burnt wood could ensure long-lasting effects to promote soil multifunctionality in Mediterranean ecosystems. Implications: We recommend using a multifunctionality approach to avoid biases in treatment success. Post-fire treatment consisting of leaving burnt logs and felled branches in close contact with the forest floor promotes the ability of the soil to sustain high values of multiple functions simultaneously in the medium term after wildfire, as compared to straw mulching application. (This paper is part of a Special Issue that includes papers on research presented at the IX International Conference on Forest Fire Research, Coimbra, Portugal, November 2022.) [ABSTRACT FROM AUTHOR]

Vineyard growth and grape yield can be significantly reduced by weeds, especially when these are located in the under-vine zone. Traditional weed management consists of recurrent tillage, which is associated with soil erosion and high fuel consumption, or herbicide applications, associated with damage to the environment and human health. In order to find alternative weed management methods, three field trials were carried out in Raimat (Lleida, NE Spain) with the aim of evaluating the suppressive effect of four mulches against weeds. Treatments included (1) straw mulch of Medicago sativa L., (2) straw mulch of Festuca arundinacea (L.) Schreb, (3) straw mulch of Hordeum vulgare L., (4) chopped pine wood mulch of Pinus sylvestris L., (5) mechanical cultivation and (6) herbicide application. The results showed that all mulches were efficient at controlling weeds (<20% of weed coverage) in the first year, compared with the two traditional methods, as long as the percentage of soil covered by mulches was high (>75%). In this way, pine mulch stood out above the straw mulches, as it achieved high soil cover during the three growing seasons of the study (>80%), with weed coverage values under 18%. This, together with the multiple benefits of mulches (improvements in the water balance and increases in soil organic matter, among others), make them a sustainable tool to be considered as an alternative to traditional under-vine weed management in vineyards. [ABSTRACT FROM AUTHOR]

The rainfed mountain plantations in semiarid areas of the Mediterranean region with conventional practices register soil erosion values much higher than soil formation rates, affecting their long-term sustainability. The objective of this study during four-year monitoring period was to evaluate the response of soil erosion and runoff to different soil-management strategies (SMS) for the most representative rainfed fruit crops: almond, olive, and vineyard. The SMS based on conservation agriculture techniques were: minimum tillage, minimum tillage with plant strips, and no-tillage with plant strips. Soil erosion and runoff patterns were examined in erosion plots on a mountain slope under each SMS. The results demonstrated that the SMS investigated reduce runoff and soil erosion compared to conventional tillage in the study area. The combination of minimum tillage with plant strips in almond and vineyard showed to be more valuable strategy in soil control than unique minimum tillage, averaging a reduction of soil erosion and runoff of 36 and 39%, respectively. As for olive, the minimum tillage with plant strips with respect to no-tillage was able to lessen both soil erosion and runoff by 36%. Likewise, this strategy proved to be the most efficient for minimizing the adverse impact of heavy rains on water erosion development on hillslopes. Since an increase of high-intensity rainfalls in the Mediterranean semi-arid areas is expected, the implementation of sustainable strategies is urgent in order to mitigate the effects of climate change. [ABSTRACT FROM AUTHOR]

Verticillium wilt, caused by Verticillium dahliae , challenges olive cultivation and an Integrated Disease Management (IDM) approach is the best-suited tool to combat it. Since 1998, an IDM strategy in an orchard (called Granon, Spain) of the susceptible cv. Picual was conducted by increasing planting density with moderately resistant cv. Frantoio, chemical weed control, and replanting of dead olives with cv. Frantoio following soil solarization. The Verticillium wilt epidemic in Granon orchard was compared to the epidemic in a non-IDM orchard (called Ancla, Spain) with plowed soil and dead Picual olives replanted with the same cultivar. Field evaluations (2012–2013) showed an incidence and severity of the disease as Picual–Ancla > Picual–Granon > Frantoio–Granon. The spatiotemporal dynamics of the Verticillium epidemics from 1998 to 2010 were monitored with digital images using SIG. The annual tree mortalities were 5.6% for Picual olives in Ancla orchard, and 3.1 and 0.7% for Picual and Frantoio olives in Granon orchard, respectively. There was a negative relationship between the mortality of olive trees (%) by the pathogen and the height (m) above sea level. The annual mortality of cv. Picual olives was positively correlated with spring rainfalls. The Index of Dispersion and beta-binomial distribution showed aggregation of Verticillium -dead olives. In conclusion, this IDM strategy considerably reduced the disease in comparison with traditional agronomic practices. [ABSTRACT FROM AUTHOR]

Olive groves on steep slopes with a low yield account for 29.6% of the total olive growing area in Andalusia, Spain. This type of olive grove is at high risk of abandonment. Thus, apart from their productive function, we should also take into consideration the ecosystem services that they provide.The diversity of Lepidoptera Rhopalocera was studied in sloping olive groves under conventional, organic, and abandoned farming systems. Line‐transect methods were used to survey butterflies in different olive grove treatments, which were defined by a combination of farming systems and soil management systems.The greatest diversity of Lepidoptera Rhopalocera was observed in organic and abandoned olive groves with cover crops. Mechanical soil tillage was found to have a negative effect in conventional and organic tillage treatments. From this viewpoint, although abandonment has economic repercussions, it does not lead to a loss of biodiversity. The environmental variables with the greatest influence are landscape complexity and the presence of areas of shrubland. The species Pyronia bathseba appears to be strongly associated with long‐abandoned olive groves.The results of this study confirm that the presence of sloping olive groves with cover crops and long‐abandoned groves set in heterogeneous landscapes and with areas of shrubland nearby, help to explain the distribution of Lepidoptera Rhopalocera communities, as well as fostering their richness and abundance. [ABSTRACT FROM AUTHOR]

Persimmons (Diospyros kaki) are trees cultivated under subtropical environmental conditions but are also found in other regions such as the Mediterranean. However, no research has been conducted to investigate soil erosion processes under Mediterranean soil management systems characterized by flood irrigation and/or tillage. The Improved Stock Unearthing Method (ISUM) for assessing long‐term soil mobilization was applied to two fields, one under tillage and the other under no‐till with herbicide within a 25‐year old Mediterranean persimmon plantation. Replicating methods used in vineyard studies, graft unións on persimmon plants were used as passive bio‐indicators of soil surface changes in this study. The tilled field showed a total soil mobilization volume of 48.4 m3 on a 408.5 m2 plot, representing a total soil loss of 52.6 Mg ha‐1 yr‐1. For the plot (468 m2) managed with no‐till and herbicide, the results indicated total soil mobilization of 33.6 m3 which translates to 31.9 Mg ha‐1 yr‐1. It is concluded that flood irrigation is able to modify the runoff pathways and landforms in Mediterranean persimmon plantations, and the flood impact is more extensive when combined with tillage. For the first time, ISUM has been successfully applied to estimate soil erosion in a plantation under flood irrigation. [ABSTRACT FROM AUTHOR]

The Mediterranean region is a climate change hotspot due to projected precipitation decreases, soil erosion, and rising temperatures in the coming decades. In such a context, wheat productivity is expected to decrease; thus, all available croplands will need to be farmed to meet food demands. It is therefore crucial to have adequate management to help balance wheat production and environmental protection in specific target environments. With this aim, we present a study in Castile and Leon (Spain) in which we assess conventional and certified organic wheat grain yield and quality. Moreover, we spatially define wheat cultivation suitability categories and monitor crop rotation practices. For wheat suitability mapping, a fuzzy interference system was used to standardize topographic (height and slope), edaphic (pH, soil erosion, organic matter, and texture), and climatic (rainfall and temperature) variables and create marginal, suitable, and very suitable wheat cultivation suitability categories. We calculated the area of wheat suitability categories with confidence intervals and discussed factors affecting productivity. Additionally, we assessed the performance of certified organic and conventionally managed fields with organic and chemical fertilization. We also examined crop rotations using Sentinel-2 data over two seasons (2020−21). Certified organic management yielded 50% less than conventional management in similar environments while maintaining grain quality. Besides management, the main causes of the yield gap are the growing environment and variety. In conventional wheat management, organic fertilization achieves comparable yields to chemical fertilization. Crop rotation practices are uncommon, and over 50% of fields rotate wheat-to-barley or wheat-to-wheat, indicating poor soil management. The region has 25% of cropland classified as marginal wheat croplands (163,503 ± 33,796 ha) producing <2500 kg/ha. Wheat organic agriculture has decreased yield gaps in marginal croplands compared to more productive areas. By farming organic wheat in marginal croplands, the best croplands might be used for more productive farming. • The studied region in Spain has 25% of cropland classified as marginal wheat croplands. • A fuzzy interference system has proven effective to decipher wheat suitability classes. • Sentinel-2 data allowed monitoring the uncommon crop rotation practices in the region. • Certified organic management yielded 50% less than conventional in similar settings. • Wheat organic agriculture has decreased yield gaps in marginal croplands. [ABSTRACT FROM AUTHOR]

The current trend toward sustainable agricultural practices creates a demand for alternatives to conventional soil management. One of the main problems for farmers is the competition for water and nutrients of weeds with the crop and the complicated management that this entails. Conventional practices such as tillage and the use of herbicides are commonly used and imply high environmental impacts while organic mulches could be an attractive sustainable alternative for soil management. Therefore, the 3-year effect of different soil management practices with organic mulches on the control of spontaneous weeds in the vine row has been studied. Three types of organic mulches [grapevine pruning debris (GPD), straw (SM) and spent mushroom compost (SMC)] and two conventional soil management methods [in-row tillage (TILL) and herbicide (HERB)] were compared on a vineyard in North Spain. For this purpose, the percentage of soil covered by weeds (PWC), the presence of each species and its effect on the vine development, and the weed community formations were analysed in each soil management. In addition, soil nutrition, soil temperature and soil water content were measured. On the one hand, SM and GPD mulches limited the presence of weeds (<30%), reducing the need for tillage maintenance and improving soil integrity. On the other hand, SMC produced excessive weed growth (>85%) that could be a problem for the farmer. Of the conventional practices, the TILL treatment was strongly affected by the timing of agricultural work and environmental conditions, with large variability between years. The results indicated that the application of organic mulches reduced the percentage of species with a harmful effect on optimal vine growth and increased plant diversity and its benefits for the ecosystem. Organic mulches are an effective alternative for soil management due to the improvement of the chemical and physical properties of the soil, the increase in the water content of the soil, the reduction of heat stress and the percentage of noxious species for optimum vine growth. • Organic mulches increase soil nutrient content and reduce the mean soil temperature. • Straw and grape pruning debris mulches controlled excessive weed cover (<30%). • Organic mulches increase the biodiversity of the spontaneous plant community. • Noxious species percentages were more abundant in conventional soil management. [ABSTRACT FROM AUTHOR]

Abstract In the Mediterranean region, floods are expected to increase as a result of climate change and knowledge of soil erosion hot spots during exceptional rainfalls is required to support mitigation measures. This study quantifies the main sediment sources during an exceptional rainfall event in 2012 (235 mm) at the outlet of two catchments located in NE Spain. To this purpose, suspended sediments were collected during the flood event, complemented with entrapped sediments in mat taken one year after the event. We used fingerprinting methodology and applied the FingerPro unmixing model to estimate the contribution from main sources. The selected tracers clearly distinguished agricultural, rangeland, subsoil and channel banks as the four potential sources in both catchments. In the Vandunchil catchment, the 8 time-integrated suspended sediment samples revealed changes in source contribution during the 2-h sampling sequence. There were relatively high contributions from rangeland, agriculture and subsoil at the beginning of the sampling, representing 30, 40 and 35% of the total source contributions, respectively. Our records captured the delivery of pulses of eroded surface soil transported by runoff with direct connectivity to the stream. The sequence was followed by a sharp increase in channel bank contribution (up to 90%) in comparison to the other sources, reflecting streambank erosion and landslide occurrence, which manifested during the flood. In contrast, in the La Reina catchment, agricultural soils contributed the most (65%) and, together with subsoils (32%), were the main sources. These results reflect the effect of the higher connectivity and slope gradient of these cultivated fields of the La Reina catchment in comparison with those of the Vandunchil catchment. We discuss the possibility of using different properties, such as radionuclides, geochemistry and magnetic measurements, as tracers to distinguish between potential sources during an exceptional event in upland Mediterranean catchments. Our results support the use of fingerprinting techniques to determine variations in source contribution and sediment provenance during flood events, as extreme rainfalls are main drivers of sediment mobilization and key factors in changing landscapes. This is essential in identifying vulnerable hot spots, in which early-stage interventions are needed, and for helping policy makers with management of soil and water resources. Graphical abstract Image 1074 Highlights • Unique opportunity to capture soil response during an exceptional event of 235 mm. • Suspended sediment properties changed during the flood event. • Source contributions varied in response to the rainstorm in a short period. • Switch from soil sources to channel bank provenance was captured during the flood. • Land use and connectivity determined the suspended sediment provenance. [ABSTRACT FROM AUTHOR]

Soil CO 2 emissions are critical for climate change modelling. Although there is a consensus about the linear or exponential relations between soil respiration and climate factors, some works have shown this abstraction to be invalid under arid and semiarid conditions, especially those in the Mediterranean-type climate. In this work, the latest empirical models were tested on previously published data from three sites representing different agricultural areas under Mediterranean conditions and contrasting soil uses. Soil heterotrophic respiration, soil temperature and volumetric water content were monitored on average every two weeks in each site over at least one year. With the findings in the three sites in Spain and Italy, it can be concluded that soil temperature was the main driver of soil respiration, as in temperate sites. However, owing to the extreme variability in climate variables, soil moisture modulates the response of soil respiration to temperature changes, and is thus another key for modelling soil respiration in Mediterranean conditions. Irrigation practices with high water inputs also substantially modify the soil respiration pattern, causing it to become similar to temperate soils. Finally, the results indicate that annual extreme values may be especially relevant in the relationship between climate variables and soil CO 2 emissions. • Different approaches were studied for soil respiration modelling. • Soil temperature is the main factor controlling Mediterranean soil CO 2 emissions. • High irrigation inputs caused the soil respiration dynamics to be similar to in temperate climates. [ABSTRACT FROM AUTHOR]

Vineyards are an intensive cultivation system and expose the soil to long-lasting stress. Many vineyard areas already show high degrees of soil degradation. To prevent further soil erosion, cover crops, which have various positive effects on the environment, are highly recommended. But, depending on the climatic conditions, cover crops can reduce grape yields and are sometimes more work intensive than bare soil management. In some areas cover crops are already widespread while in others bare soil is dominant. In this qualitative study, we explore the attitudes of European winegrowers towards cover crops and determine the background for differences in the adoption of greened vineyards. Thus, we conducted focus groups with winegrowers in two different regions, namely Coteaux du Layon in France and Montilla-Moriles in Spain. In this setting, the transregional differences are mainly based on the climatic conditions but also on different business structures and knowledge levels. Direct sellers seem to be more attentive to the environment and use cover crops more often than farmers which sell their grapes to cooperatives. [ABSTRACT FROM AUTHOR]

To ensure sustainable agricultural management, there is a need not only to quantify soil erosion rates but also to obtain information on the status of soil water content and soil loss under different soil types and land uses. A clear understanding of the temporal dynamics and the soil moisture spatial variability (SMSV) will help to control soil degradation by hydrological processes. This study represents the first attempt connecting cosmic-ray neutron sensors (CRNS) with soil erosion research, a novel approach to explore the complex relationships between soil water content (SWC) and soil redistribution processes using two of the most powerful nuclear techniques, CRNS and fallout 137Cs. Our preliminary results indicate that CRNS captured soil moisture dynamics along the study toposequence and demonstrated the sensitivity of neutron sensors to investigate the effect of parent material on soil water content. The Empirical Orthogonal Function (EOF) analysis of the comprehensive data from seven CRNS surveys revealed that one dominant spatial structure (EOF1) explains 89.2% of SMSV. The soil redistribution rates estimated with 137Cs at the nine locations along the hillslope, together with local factors related to soil properties (SOC, soil depth, hydraulic conductivity) and land use showed significant correlations with EOF. This study provides strong field evidence that soil type significantly affect SMSV, highlighting the key impact on soil erosion and sedimentation rates. Nevertheless, more research is needed to investigate the specific contributions of soil properties to the spatial variability of soil moisture and their subsequent effects on soil redistribution dynamics of interest for soil management. [Display omitted] • Combining nuclear techniques for exploring soil moisture and soil redistribution. • Parent material controls soil moisture spatial variability (SMSV). • Seven CRNS surveys at nine locations captured 85.5% of SMSV using EOF analysis. • Soil depth, hydraulic conductivity, erosion rates and SOC significantly affect SVSM. • CRNS and 137Cs provide insights into the link between SWC and soil redistribution. [ABSTRACT FROM AUTHOR]

The soils of Mediterranean vineyards are usually managed with continuous tillage, resulting in bare soil, low infiltration and high soil erosion rates. Soil nutrients, such as nitrogen, could be lost dissolved in the runoff, causing a decrease in soil fertility on such degraded soils and producing eutrophication downstream. The influences of groundcover on the soil erosion processes and sediment yields in Mediterranean vineyards have been widely addressed. However, the runoff process itself, excluding the effect of raindrop impacts, has barely been studied. Thus, a field runoff simulator was built to assess runoff and nutrient losses under different soil management strategies in Central Spain. In the winter of the 2012–2013, four vineyards were selected, and two types of groundcover were established to compare with conventional tillage (T): spontaneous vegetation (CS) and seeded Brachypodium distachyon (CB). In 2014 and 2015, 72 runoff simulations were performed to assess the influence of the two different types of groundcover on the dissolved mineral nitrogen losses in runoff. The results showed that spontaneous vegetation cover was the most effective management choice to reduce runoff and nitrogen loss by producing 3 times less runoff than conventional tillage and 6 times less nitrate loss. Conventional tillage resulted in higher mineral nitrogen loss because it produced more runoff and higher runoff nitrate concentrations. The vegetation cover had a strong influence on runoff and nitrogen losses, while the slope angle and rock fragment cover showed a negligible impact. [ABSTRACT FROM AUTHOR]

Cereal and olive cultivation are thought to have played a major role in triggering soil erosion since humans have settled in the south of Spain and in increasing gully activity since the relatively recent intensification of olive cultivation. To test these hypotheses, we dated the sediments and reconstructed the soil erosion history of two gullied catchments, in Baena and Montefrío, both located in the South of Spain but with well differentiated land management histories. To date the sediments, we established a multi-proxy chronostratigraphy based on radiocarbon dating, optical stimulated luminescence and archaeology. In addition, we used the reconstructed land management history of the two catchments and aerial photographs. The reconstructed soil histories of the two catchments suggest a close link between agricultural land management practices and soil erosion in the last seven millennia. Notably, results indicate that soil erosion activity started earlier in Montefrío, corresponding to the first human settlements seven millennia ago. However, in the last two millennia erosion and gully activity in Baena have rapidly overtaken that of the Montefrío due to a more intense economic and agricultural activity of the former. In the last decades, erosion and gully activity in both catchments have been very high due to the intensification of the olive cultivation. [ABSTRACT FROM AUTHOR]

The intensification of agricultural systems has caused a noticeable impact on agro-ecosystem services. Thus, the adoption of more sustainable agricultural practices such as crop diversification and reduction of external inputs represent an alternative strategy to minimize the impacts of intensive agricultural systems to the environment. This study aimed at evaluating the effects of crop rotation, conservation tillage, and low-input strategies on soil quality and farming performance using a set of 7 indicators based on a fuzzy logic approach. Data were collected from three Mediterranean long-term field experiments (LTEs) mostly oriented on cereal-based and vegetables cropping systems, located in Spain and Italy. The selected agro-environmental indicators clearly discriminated both from a geographical point of view and between monoculture and diversification, showing their suitability for the evaluation of diversified cropping systems. Such indicators highlighted that implementing crop diversification and reducing soil disturbance and chemical inputs enhanced soil quality. In this context, the most significant effects of diversified cropping strategies were the increase of crucial variables such as soil organic carbon (SOC), total nitrogen (TN), available phosphorus (P av), and bulk density (BD) maintaining a stability of yields in all the three LTEs. These results provide strong evidence for the benefits of crop diversification in Mediterranean areas, highlighting that diversification represents a very promising strategy for more sustainable land management. Simple and composite indicators calculated using fuzzy method can be proposed as tool to assess the effects of diversification strategies on cropping systems performance. This approach can be used to define local solutions to help the re-design of cropping system through crop diversification transition across Europe. • This study assesses the crop diversification effects in 3 Mediterranean areas. • Indicators based on a fuzzy logic approach to evaluate crop diversification effects. • Rotation, no-tillage, biodynamic vegetable systems enhanced soil quality. • All the measured indicators are affected by soil management. [ABSTRACT FROM AUTHOR]

A portfolio of agricultural practices is now available that can contribute to reaching European mitigation targets. Among them, the management of agricultural soils has a large potential for reducing GHG emissions or sequestering carbon. Many of the practices are based on well tested agronomic and technical know-how, with proven benefits for farmers and the environment. A suite of practices has to be used since none of the practices can provide a unique solution. However, there are limitations in the process of policy development: (a) agricultural activities are based on biological processes and thus, these practices are location specific and climate, soils and crops determine their agronomic potential; (b) since agriculture sustains rural communities, the costs and potential for implementation have also to be regionally evaluated and (c) the aggregated regional potential of the combination of practices has to be defined in order to inform abatement targets. We believe that, when implementing mitigation practices, three questions are important: Are they cost-effective for farmers? Do they reduce GHG emissions? What policies favour their implementation? This study addressed these questions in three sequential steps. First, mapping the use of representative soil management practices in the European regions to provide a spatial context to upscale the local results. Second, using a Marginal Abatement Cost Curve (MACC) in a Mediterranean case study (NE Spain) for ranking soil management practices in terms of their cost-effectiveness. Finally, using a wedge approach of the practices as a complementary tool to link science to mitigation policy. A set of soil management practices was found to be financially attractive for Mediterranean farmers, which in turn could achieve significant abatements (e.g., 1.34 MtCO 2 e in the case study region). The quantitative analysis was completed by a discussion of potential farming and policy choices to shape realistic mitigation policy at European regional level. [ABSTRACT FROM AUTHOR]

Olives, Olea europaea L., are one of the most important crops in Spain. They are currently produced under three management systems that involve different aspects of soil and pest management, productivity, and crop economy: organic, (integrated pest management--IPM), and conventional. Here, we studied how these systems affect the spiders, the natural enemies of olive grove pests, and performed a detailed analysis of their assemblage. The study was performed during one season in 18 olive groves in Andalusia, Spain, and included both ground-dwelling and canopy species. We found that the organic system supported a significantly higher level of abundance and diversity of canopy spiders than the IPM and conventional systems. Plowing had a negative effect on spider abundance and diversity. However, the presence of hedge vegetation had a positive effect on the spiders. The practices affected the guild structure differently, with some guilds supported by organic and others by IPM. It is suggested that sustainability (in terms of pest control) in olive grove agroecosystems may be obtained by maintaining hedge vegetation regardless of the management system. [ABSTRACT FROM AUTHOR]

Abstract: This study reports the soil–plant relationships within a protected landscape in semiarid SE Spain that includes salt marshes and temporary streams and that is affected by agricultural water leaching. The main objective was to establish a conceptual model in order to use vegetation as bioindicator of soil conditions. With this model, environmental changes – based on the observation of vegetation – could be detectable, allowing the prevention of environmental impacts and the improvement of the environmental management of the studied area. Eight sampling stations with a total of 39 plots were established for the sampling of vegetation (floristic composition and species abundance) and soil (moisture, pH, redox potential, electrical conductivity and soluble ions). Multivariate analysis showed that vegetation was closely related to soil moisture and salinity. The soils colonised by steppe grasses (dominated by Lygeum spartum) and halophilus and halonitrophilus shrubs (dominated by Suaeda vera and Limonium spp.) were the driest (moisture <~20%) and least saline (EC <~30dSm−1). Phragmites australis, Sarcocornia fruticosa and Arthrocnemum macrostachyum dominated in the most saline and wettest soils. P. australis reached maximum cover at EC values ~40dS m−1 and soil moisture ~30% and consistently appeared on those soils with lower seasonal contrasts of moisture and salinity. Between 30 and 80dSm−1 of soil salinity, S. fruticosa reached maximum cover (~100%) while A. macrostachyum did not exceed ~80%. Outside this range of salinity S. fruticosa declined (cover <10%), while the other species maintained cover >~40%. In addition, A. macrostachyum grew in soils with stronger seasonal changes of moisture and salinity. Based on the model established, if an expansion of P. australis is detected, an increase in soil moisture and a decrease in soil salinity during the year could be inferred. These changes could be due to an increased entry of effluents of fresh and/or brackish water from agricultural areas. In turn, an increase in the cover of A. macrostachyum would indicate higher soil salinity, which could be a consequence of an increase in the evaporation rates (due to rising temperatures) and a decrease in rainfall (predicted consequences of global warming). The expansion of S. fruticosa would be favoured under relatively high soil salinity conditions (which limit P. australis expansion) jointly with high soil moisture, without strong seasonal changes (which limit A. macrostachyum expansion). Our results support the role of vegetation as bioindicator of disturbances and the use of soil–plant relationships models to improve the environmental management of saline ecosystems. [Copyright &y& Elsevier]

The effect of two post-fire stabilisation techniques (Seeding and Mulching) on trace element (Al, B, Co, Cu, Fe, Mn, Mo and Zn) losses with eroded sediments was evaluated over a 13-month period following an experimental fire in a steep shrubland of a temperate-humid region (north-west Spain). With time, concentration of extractable Mn, Zn and Cu in sediments decreased, Fe tended to increase and Al, Co, B and Mo varied without a clear trend. Most sediments and trace element losses occurred during the first 3 months post-fire. Compared with the available elements in ash + burned topsoil, the fraction lost with sediments was highest for Mo (10-16%), intermediate for Mn (4%) and Zn (3%) and low for the rest (0.4-1.2%). Although minor effects of stabilisation techniques on element concentrations were found, accumulated mass losses of trace elements decreased 6-12 times in Mulching because of its 10-fold lower soil erosion rate; no significant changes were found in Seeding. Sediment nutrient losses are probably more important than those published for smoke, leaching or volatilisation. Our results suggest that the Zn and Cu enrichment in sediments from the first erosion events increase the risk of downslope water and soil contamination. In conclusion, soil stabilisation techniques are useful to prevent post-fire ecosystem damage. [ABSTRACT FROM AUTHOR]

The hydro-physical properties of gypseous soils, which are commonly associated with dry climates, determine the productivity of rangelands and croplands. The objective of this paper is to study, in the semiarid central Ebro Basin, NE Spain, some hydro-physical properties of gypseous soils under five different contrasted soil managements: soils of ungrazed (N) and grazed (GR) uncultivated lands, and freshly moldboard tilled (MB), cropped (C), and fallowed (F) agricultural soils. The gypsum content of the studied soils, with concentrations that are natural, ranged from 50 to 92%. The soil bulk density (ρb), saturated sorptivity (S10), hydraulic conductivity (K10), and the water retention curve (WRC) of undisturbed soil samples from the 0–10 cm deep soil layer after removing the soil surface crust were calculated. Soil penetration resistance (SPR) for the upper 10 cm soil layer was also measured. Additional measurements of soil surface crust sorptivity (Scrust) and hydraulic conductivity (Kcrust) were conducted. Livestock trampling in GR promoted the highest ρband SPR values. The lack of soil disturbance in N caused that this treatment showed the lowest values ofScrustandKcrust, but the highestS10andK10. The specific behavior of gypseous soils, whose loose aggregates easily collapse during the soil wetting process, showed that the MB freshly tilled soil produced the lowest values ofS10andK10. A typical bimodal function of the WRC was found. Pore size distribution was affected by the soil treatment, with the highest and lowest values under MB and GR treatments, respectively. [ABSTRACT FROM PUBLISHER]

Water deficit is a serious problem for most agricultural crops, especially in arid-semiarid regions, and limits sustainable development. Production can be improved by reducing evapotranspiration and loss of infiltrated water by the use of a plastic cover. We monitored soil moisture fortnightly over 1 yr using a neutron probe near four trees in an olive grove ( Olea europaea, var. Arbequina), two of which had a plastic cover buried in the topsoil around them. These trees were monitored using three neutron probe access tubes per tree to compare the behaviour of soil moisture over time with two other identically instrumented and nearby trees with no cover. Analysis was based on the resultant moisture profiles. The plastic cover retained moisture and increased soil water residence time. During the dry season, the amount of water retained in the plots was at most 15-20% greater in the mid-season and at least 5-6% greater at the end of season than in the central part of the plots near the trunk. The plastic cover was effective to ca. 50 cm with maximum water content near the soil surface. During the wet season, the cover did not affect soil water. Soil moisture was greater near the tree trunk as a result of stemflow and throughfall. [ABSTRACT FROM AUTHOR]

An analysis of the sensitivity of synthetic aperture radar (SAR) backscatter (σo) to crop and soil conditions was conducted using 57 RADARSAT-2 C-band quad-polarized SAR images acquired from April to September 2009 for large fields of wheat, barley, oat, corn, onion, and alfalfa in Barrax, Spain. Preliminary results showed that the cross-polarized σHVo was particularly useful for monitoring both crop and soil conditions and was the least sensitive to differences in beam incidence angle. The greatest separability of barley, corn, and onion occurred in spring after the barley had been harvested or in the narrow time window associated with grain crop heading when corn and onion were still immature. The time series of σo offered reliable information about crop growth stage, such as jointing and heading in grain crops and leaf growth and reproduction in corn and onion. There was a positive correlation between σo and the Normalized Difference Vegetation Index for onion and corn but not for all crops, and the impact of view direction and incidence angle on the time series was minimal compared to the signal response to crop and soil conditions. Related to planning for future C-band SAR missions, we found that quad-polarization with image acquisition frequency from 3-6 days was best suited for distinguishing crop types and for monitoring crop phenology, single- or dual-polarization with an acquisition frequency of 3-6 days was sufficient for mapping crop green biomass, and single- or dual-polarization with daily image acquisition was necessary to capture rapid changes in soil moisture condition. [ABSTRACT FROM AUTHOR]

Abstract: Conservation tillage has been encouraged as a management alternative to preserve soil and water resources in semiarid Aragon (NE Spain). In fact, its adoption by farmers, and especially of no tillage (NT) systems, has increased in recent years. However, little information concerning the soils on which these techniques are applied is available for this region. The objective of this study was to assess the potential of NT to increase organic carbon content at the soil surface (0–20cm) in rainfed Aragon. To this aim, 22 pairs of adjacent farm fields under NT and conventional tillage (CT) were compared in different cereal production areas. The fields were under continuous NT between 5 and 19 years but half were over 10 years. Soil organic carbon (SOC) in NT ranged from 7.06 to 18.53gkg−1 (0–20cm depth) and was higher than 12gkg−1 in nearly 30% of the fields. These contents represented between 8% less (only one case) and 55% more SOC under NT than under CT with an average gain of 20% in favour of NT. The highest SOC contents were found in the NT fields of longer duration (>10 years) and/or managed with practices that enhance the return of more crop biomass to the soil (complete residue return, cropping intensification and manure application). The identification of the current management practices used by farmers has allowed us to know the diversity of the NT-based cropping systems and the reality of the conservation agriculture in our region. Overall, results from this on-farm study indicate that NT can be recommended as a viable alternative to CT to increase organic carbon at the soil surface in cereal production areas of Aragon. [Copyright &y& Elsevier]

In Galicia (northwestern Spain), cultivated soils developed on schists from the Ordenes series are susceptible to surface degradation, mostly when soil organic content decreases. Therefore, management systems that protect the soil and increase its organic-matter content should also improve its quality. However, tillage practices may cause crusting. Degraded soil surface conditions favor surface runoff, thus enhancing nutrient losses. This study examined the effect of applying crop residues to the soil surface on the basic cation nutrient [calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na)] losses by runoff from a tilled soil with relatively low organic-matter content. Runoff and sediment yield were measured on 1-m2 plots using a rainfall simulator with constant 65 mm h−1 intensity. Four successive rainfall applications were performed, the first three at 25 mm each and the last at 65 mm. Added corn straw varied between 0 and 4 t ha−1 in the five treatments studied. Total and dissolved concentrations of the elements studied showed a tendency to decrease due to the effect of corn straw on soil losses. After 140 mm cumulative rainfall, total nutrient losses were as follows: Ca from 12.32 to 28.94 mg L−1, Mg from 20.81 to 148.90 mg L−1, K from 14.20 to 35.17 mg L−1, and Na from 14.99 to 23.41 mg L−1. The relative contribution of the dissolved fraction to the total nutrient content loss was highly variable, being up to 90% for Na. The results confirm that corn residues applied to a degraded soil, with low structural stability, prevent cation nutrient losses. [ABSTRACT FROM PUBLISHER]

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Currently, there is little information about soil organic carbon (SOC) stocks and changes in Mediterranean areas at a regional scale. We modelled an area of 95 269 km2 in northeast Spain using the Global Environmental Facility Soil Organic Carbon (GEFSOC) system to predict SOC stocks and changes in pasture, forest and agricultural soils. The spatial distribution of the different land-use categories and their change over time was obtained by using the Corine database and official Spanish statistics on land use from 1926 to 2007. The model predicted the largest current SOC stock in forest soils at 578 Tg C. Agricultural soils were the second largest SOC reservoir, containing 244 Tg C. During the last 30 years, the model predicted a total SOC gain in the 0-30-cm soil layer of 34 Tg C. Forest and grassland-pasture soils had a decline in their stored SOC of 5 and 3 Tg C, respectively, because of the reduction in the soil surface occupied by both classes. The greatest SOC gain was predicted in agricultural soils with 42 Tg C caused by changes in management, which led to increases in C inputs. Although model uncertainty was not quantified, some hypothetical assumptions about the initialization and parameterization of the model could be potential sources of uncertainty. Our simulations predicted that in northeast Spain soil management has contributed to the sequestration of substantial amounts of atmospheric CO2 during the last 30 years. More research is needed in order to study the potential role of soils as atmospheric CO2 sinks under different managements and climatic conditions. [ABSTRACT FROM AUTHOR]

To resolve the spatial variation in soil properties intensively is expensive, but such knowledge is essential to manage the soil better and to achieve greater economic and environmental benefits. The objective of this study was to determine whether the soil apparent electrical conductivity (EC), alone or combined with other variables, is a useful alternative for providing detailed information on the soil in the Extremadura region of Spain. Apparent soil electrical conductivity was measured and geographically weighted regression was used to characterize the spatial variation in soil properties, which in turn can be used for soil management. This study shows that soil cation exchange capacity, calcium content, clay percentage and pH have a relatively strong spatial correlation with EC in the soil of the study area. [ABSTRACT FROM AUTHOR]

Abstract: Organic matter from surface horizons of olive grove soils under organic and conventional management, compared to natural vegetation (undisturbed), on two contrasting geological substrates (colluvial limestones and marls) in a semi-arid Mediterranean area were characterized to evaluate the influence of management and soil type. Higher percentages of total carbon, total humic extract and humin fractions were observed in the organic management and undisturbed soil samples. The main qualitative functional and compositional changes induced by management were related to the aromaticity of humic acids (HA), which were lower in organically managed samples than conventional management. This may be due to continuous effective incorporation of alkyl compounds from spontaneous vegetation, which would explain its typical lignin patterns and higher E4/E6 ratios (visible spectra absorbance to 465 and 665nm). The main qualitative changes affecting organic matter were induced by the geological substrate (soil type). Soil samples from marls had a lower humic to fulvic acids ratio, and their HA were more aliphatic (with respect to the 2920cm−1 infrared band) and more intense with organic management. These samples also had well-defined amide and carbohydrate infrared bands (labile compounds) and lower E4 optical density. These results showed less efficient biodegradation of aliphatic components. On the contrary, greater decomposition of organic matter was detected in the HA fraction from colluvial limestones, which was transformed into more stable and evolved forms of humus. This may be due to overlapping of current soil management and its biogenic background, representative of the original soil in this area, where pedogenic development is more intense. Characteristics of soil organic matter in the undisturbed soil were between conventional and organic management, which shows how difficult it is to find natural, well-conserved soil to serve as a reference in the agricultural context studied. Our findings reveal that more sustainable soil management and development of management practices more in harmony with the original evolution of the soil and its relationship to the parent material are especially important in this area. [Copyright &y& Elsevier]

Abstract: Olive orchards are an important agro-ecosystem in the Mediterranean. Soil erosion is a widely recognized threat to their sustainability. However, the variability of short-term soil erosion measurements and the limited understanding of driving processes result in a considerable uncertainty over the long-term effects of soil erosion. This study aims at measuring and modelling soil erosion rates in olive orchards over a 250-year period, and relating these to changes in management practices and yield, as documented from historical sources. In three study areas in S-Spain, the height of relic tree mounds was measured in olive orchards dated between 153 and 291 years old to determine soil profile truncation. Measured average soil erosion rates were between 29 and 47tha−1 year−1. Historical documents allowed characterizing land management since 1752 in eight distinct periods. This information was then used to calibrate a soil erosion model, combining water and tillage erosion. The model reproduced the temporal patterns in soil erosion rates and showed considerable historical variation: between 8 and 124tha−1 year−1 for water and between 3 and 42tha−1 year−1 for tillage. Mainly due to improved agronomic practices, yield was not affected by soil erosion and has continuously increased over time. [Copyright &y& Elsevier]

The impacts of tillage and cropping sequences on soil organic matter and nutrients have been frequently reported to affect the uppermost soil layers, but there is little published information concerning effects at greater depth. This article reports results on the distribution of soil organic carbon (SOC), active carbon (AC), N, Olsen-P and extractable K within 100 cm in short (4 yr) and long (16 yr) term experiments under different tillage systems. Short (TT) and long (TT) traditional tillage are compared with conservation tillage, reduced (RT) and non-tillage (NT). The results show more accumulation of SOC in the near-surface under RT and NT in both experiments compared with traditional tillage. Moreover, greater C content occurs to 40 cm depth in the long-term experiment. The results demonstrate the importance of time on C accumulation, not only in near-surface layers but also at greater depths. Active C is an indicator of the increase in soil quality in the long-term experiment. This trend is only apparent for the first 10 cm in the short-term experiment. Patterns in N, Olsen-P and extractable K are similar to that of SOC. However, only extractable K is significantly greater in soil under conservation tillage (RT and NT) after short and long periods. Potassium availability is a good indicator of the changes caused by tillage. Our results indicate that studies of soils at depth could be very useful in long-term experiments to demonstrate the effect of conservation tillage on C and nutrient distribution. [ABSTRACT FROM AUTHOR]

Abstract: Clean cultivation is a common practice in rainfed orchards; however, it may have detrimental effects on soil properties. This study examines the effect of different soil management systems on physical, chemical, and biochemical properties in a hypercalcic Calcisol in rainfed almond orchards (Prunus dulcis (Mill.) D.A. Webb) in SE Spain. Four types of soil management (main-plot treatments) were compared to a frequently tilled orchard system (FT: three or four tillages per year). The four types of soil management were: fencing (SF) of a flock of 130 sheep in 0.4ha and grass cover was kept throughout the growing season; native vegetation (NV) that was allowed to grow; cover crop (CC) composed of legumes and crucifers; and reduced tillage (RT) comprising autumn and spring chisel ploughing. Each type of soil management was split into two grazing treatments (subplot treatments): with and without grazing. Our results supported the hypothesis that clean cultivation, i.e., FT, has deleterious effects on soil properties compared with managed groundcover. Compared with FT treatment, at the end of the experiment, the rest of treatments had higher wet aggregate stability (except the SF treatment), soil organic carbon (10.6gkg−1 vs. 5.4gkg−1, mean groundcover treatments vs. FT), total nitrogen (1.35gkg−1 vs. 0.83gkg−1, mean groundcover treatments vs. FT), available potassium (332mgkg−1 vs. 187mgkg−1, mean groundcover treatments vs. FT), and dehydrogenase (2.6μgINTFg−1 h−1 vs. 1.9μgINTFg−1 h−1, mean groundcover treatments vs. FT), arylsulphatase (12.8μgPNPg−1 h−1 vs. 6.5μgPNPg−1 h−1, mean groundcover treatments vs. FT), β-glucosidase (569μgPNPg−1 h−1 vs. 300μgPNPg−1 h−1, mean groundcover treatments vs. FT), and phosphatase activity (394μgPNPg−1 h−1 vs. 220μgPNPg−1 h−1, mean groundcover treatments vs. FT). Grazed plots had higher water content in soil (10gH2Okgsoil−1 vs. 9.4gH2Okgsoil−1, grazed vs. not grazed plots) and greater levels of arylsulphatase (12μgPNPg−1 h−1 vs. 11μgPNPg−1 h−1, grazed vs. not grazed plots), β-glucosidase (582μgPNPg−1 h−1 vs. 491μgPNPg−1 h−1, grazed vs. not grazed plots), and phosphatase activity (396μgPNPg−1 h−1 vs. 345μgPNPg−1 h−1, grazed vs. not grazed plots), in late spring, and this is attributed to the reduction of evapotranspiration and to the stimulation of root activity by means of plant defoliation. In conclusion, under the conditions of this study, managements including grass cover improved physical, chemical and biological properties of soil compared with frequent tillage, particularly when grass was early removed by grazing. [Copyright &y& Elsevier]

Abstract: Minimum (MT) or no tillage (NT) and increased cropping intensity can enhance soil structure and raise carbon sequestration in agricultural soils. The effectiveness of these procedures depends on soil type, crops, and tillage management systems. Increases in the organic carbon content may be affected by crop type, crop rotation and the quality and quantity of crop residues left on the soil surface. Soil organic carbon (SOC) is a good indicator of soil quality and conservation. The present study was conducted from 1994 to 2004 at Torrepadierne, Burgos, a cereal farming area in Spain, on Typic Calcixerolls soil with a 1.8% soil organic matter (SOM) content. The average annual rainfall in the area is 448mm. A split-plot experimental design was used, in which the main factor was the tillage system – conventional (CT), minimum (MT) or no-till (NT) – and the sub-factor crop rotation – cereal/cereal (C–C), cereal/fallow (C–F) and cereal/legume (C–L). Fallow/cereal and legume/cereal were added to these sequences to have the same crops every year. The present study was conducted to determine the effect of tillage systems and cropping sequences on SOC patterns after 10 years of soil management. At a depth of 0–10cm, the SOC content was significantly higher with NT than CT or MT, by 58% and 11%, respectively. SOC values were 41% higher with MT, in turn, than with CT. At a depth of 10–20cm, the SOC content was 30% higher with NT than with CT and 7% higher than with MT. And at 20–30cm, it was 7% higher with MT than with CT, 12% higher with NT than CT and 9% higher with no-till than minimum-till. In 2004, at the end of the 10 years period, SOC was 25% greater with NT than CT, 16% greater with NT than MT, and 17% higher with MT than CT. Crop rotation was not observed to have any significant effect on the SOC content in 2004, however. These findings suggest that carbon sequestration in the 30cm layer can be improved if NT or MT are used in lieu of conventional practice. The total crop residue returning to the soil was significantly greater in plots sown with legume after cereal harvest than in plots left fallow. It also enhanced SOC sequestration in non- or minimally tilled soils. [Copyright &y& Elsevier]

Abstract: Biochemical properties are considered to be the best indicators available at present for assessing soil quality. However, there are still many gaps in our knowledge about how these properties are affected by abiotic factors and how these factors interact with soil management. With the aim of understanding how climate and soil management affect soil biochemical properties in grasslands soils from a temperate-humid area (Galicia, NW Spain), a total of 60 soils were analyzed for several microbial and biochemical properties. Grasslands were divided into groups according to the type of management applied (native compared with intensive) and to the climate in the area where they were sampled (Mediterranean subhumid with centroeuropean drift climate compared with Atlantic climate). We found that management had a greater influence on soil biochemical properties than climate. Altitude, which strongly influences climate in the region where the soils were analyzed, was found to be a significant factor that affected most soil biochemical properties. In conclusion, the results show that microbially-mediated processes are greatly affected by both, management and abiotic factors and that, for some properties (like net N mineralization and cellulase and casein-protease activities), abiotic factors can have an important influence on soil biochemical properties. [Copyright &y& Elsevier]

The Mediterranean basin holds the greatest area of horticultural crops grown under plastic in the world. Spain houses almost 50,000 ha of greenhouses and is one of the largest suppliers of European Union markets. Soilless cropping systems constitute an efficient production practice used in greenhouses and lessen the limitations arising from the ban of methyl bromide. Soilless cultivation is associated with the use of expensive technology, which makes farmers consider such adoption carefully. The aim of this work is to statistically identify the factors that significantly influence the timing of adopting soilless cultivation by using duration analysis. The study focuses on Mediterranean greenhouses, specifically horticultural producers in the southeast of Spain. The results suggest that certain individual characteristics as well as aspects of a social nature exert a favorable influence by reducing the delay in adopting soilless cultivation. Furthermore, technical complexity, commercial aspects related to price, and the repercussion of policies regulating methyl bromide use are also discussed in this work. [ABSTRACT FROM AUTHOR]

The article assesses the concentrated erosion rates in Galicia, Spain. The region is, subject to high erosion risk due to natural condition such as steep slopes. The state of its soil surface is characterized by crust development, tillage features and roughness degree. Low values of soil erosion are dominant in the region, but large values of rill and ephemeral gully erosion also occur.

Abstract: Forty-six organic olive orchards under different soil management systems were evaluated in the province of Córdoba (southern Spain) to assess the state of their soil properties and the degree of degradation of their topsoil, and the possibilities for monitoring any soil degradation risk. Our study indicated that 55% of the olive farms sampled (OF) presented a low soil degradation, in which most of their deficiencies were a low content in some soil nutrients such as P, which may be partly due to the moderate fertility of some soils in the area. This result could be explained by the low or moderate intensity of the farming systems used in a large part of the study area. Seven percent of the sampled OFs had a large number of physical, chemical and biological soil properties, that could be considered as being degraded, and these olive orchards were classified as seriously degraded. The remaining OFs were in an intermediate state. The degree of soil degradation was not correlated with any specific soil management method or with predicted soil erosion rates, suggesting that it was the result of specific and varied on-farm conditions difficult to detect without a field evaluation. Three soil degradation indexes were obtained through a principal component analysis of the soil properties analyzed. These indexes were able to distinguish between OFs with low soil degradation and those in a serious state of degradation. Two of the indexes are basically integrative ones that can be used in relatively large surveys considering a large number of soil properties. The third index developed used only three soil properties, organic C, water stable macroaggregates, and extractable P, and has the potential to be used as a relatively easy and inexpensive screening test of soil degradation for organic olive farms in the area. [Copyright &y& Elsevier]

In the mountainous areas of Eastern Spain, soils have been cultivated in terraced orchards for centuries, although in the last decades, almond orchards are being abandoned. For this study, we selected four locations in SE Spain, with a similar vegetation mosaic, constituting forest, almond tree orchards, and orchards abandoned between 10 to 15 years previous to sampling. The main objective was to investigate the effects of changes in land use from forest to agricultural and posterior land abandonment on various physical, chemical, and biochemical properties. In all locations, all properties showed the highest values in forest soils, excepting pH and some eco-physiological ratios which were lowest under this land use. Abandoned agricultural soils showed a slight recovery in some properties compared to agricultural soils, the biochemical properties being the most sensitive indicators in reflecting these changes. All these results indicate that after land abandonment, soil microorganisms are more active as a consequence of the increment in the vegetation cover, with higher inputs as litter and root exudates. Moreover, the stopping of tillage may also have favored the increments in microbial biomass and activity. Nonetheless, these values are still low compared to forest soils, reflecting that 10-15 years of abandonment is not long enough to achieve a significant recovery in soil properties under semi-arid Mediterranean conditions. The metabolic quotient (qCO2) showed no general pattern in all locations in terms of land use, suggesting that this ratio is not specific enough to be used as an indicator in ecosystem succession. [ABSTRACT FROM AUTHOR]

Abstract  Although soil biochemical properties are considered to be good indicators of changes in soil quality, few studies have been made of the changes in biochemical properties brought about by anthropogenic disturbance of grassland ecosystems. In the present study, several biochemical properties were analysed in 31 grassland soils subjected to a high level of management, and the values obtained were compared with known values corresponding to native grasslands from the same region (Galicia, NW Spain). The 31 managed grasslands were divided into two groups (re-sown grasslands and improved grasslands) according to their management and past land use. The biochemical properties studied were: labile carbon, microbial biomass carbon, microbial respiration, metabolic quotient, net nitrogen mineralisation and the activities of dehydrogenase, catalase, phosphodiesterase, phosphomonoesterase, casein hydrolysing proteases, benzoyl arginamide (BAA)-hydrolysing proteases, urease, cellulase, ß-glucosidase, invertase and arylsulphatase. Managed grasslands exhibited lower values of soil biochemical properties than native grasslands. Three biochemical equilibrium equations were used to compare soil quality in managed and native grasslands. One of the equations did not show any significant difference between the groups of grassland soils considered. In contrast, two of the equations showed similar soil quality for improved and native grasslands, while re-sown grasslands exhibited a loss of soil quality when compared to native grassland soils. [ABSTRACT FROM AUTHOR]

Deteriorating soil quality in arid areas is related primarily to inappropriate farming techniques. The use of environmentally friendly agriculture practices has proven to be effective in restoring or improving soil quality and health in these areas. In this study, four long-term approaches to olive–orchard management, categorized by the presence/absence of two main factors – cover crops and chemical weed control – were evaluated using biological indicators of soil quality. Soil bacterial population size and community structure were estimated by real-time PCR assays targeting 16S rRNA genes and denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA fragments (PCR–DGGE), respectively, and the activity of six enzymes (dehydrogenase, o-diphenoloxidase, β-glucosidase, phosphatase, urease and arylsulphatase) representative of the C, P, N, and S cycles were determined. Covered soils exhibited greater bacterial biomass and diversity, as well as higher microbial functional diversity than non-covered soils. The elimination of weeds with herbicides reduced the microbial functional diversity in covered soil but did not affect the other microbiological parameters, revealing that the effect of the cover crop predominated. When non-covered soil was considered, the lowest values of microbial activity and diversity were found when weeds were controlled with chemical methods. The results of this study reveal that covered soils are the best option when olive orchards are managed under rainfed conditions. [Copyright &y& Elsevier]

This research examines several indicators of soil quality in Spanish olive grove through Delphi methodology, in particular, texture, fertility, colour, depth, compaction, aeration, organic matter and water infiltration. This paper describes the farmer's perception about levels of soil erosion in the studied zone, taking into account their level of adoption of agrarian innovations and their attitude towards economic risk related to the application of new technologies. The panel of experts selected is composed of 63 growers in the upper basin of Genil River in 2005; this area is characterized by hillside olive groves and medium-high levels of soil erosion, so that farming is heavily dependent on soil conservation practices, specifically by tillage following contour lines, no-tillage with herbicides and maintaining of pruning on the top soil (by preliminary survey at 2004), as well as its promotion through the recent European agri-environment legislation in the area. [ABSTRACT FROM AUTHOR]

The evolution of soil chemical properties over 20 years was monitored to assess the effects of the change in soil management from a rainfed to an irrigated model and the use of organic amendments and crop rotation. Intensive agriculture has been the activity that has caused most degradation and contamination of this soil. Long-term monitoring of the soil profile made it possible to assess its response to the application of sustainable agricultural techniques intended to offset these effects. Three profiles of the same soil were studied—P1 (1998), P2 (2003), P3 (2017)—to show the evolution in time and space. An incipient degradation process was detected in the first five years, verified by increases in salinity (2.3 dS m−1), exchangeable Na (0.5 g kg−1), and TN (1.3 g kg−1) in P2 in comparison with P1 (1.0, 0.2, and 1.1, respectively). There was also leaching towards the deep horizons for TN (0.4, 0.9, and 0.7 g kg−1 for P1, P2, and P3, respectively), and for assimilable elements such as P (1.1, 6.4, and 3.8), Fe (2.0, 2.1, and 5.6), Mn (0.3, 6.5, and 1.9), Zn (0.3, 0.5, and 0.9), and Cu (0.5, 0.6, and 1.3) (all mg kg−1, for P1, P2, and P3, respectively). Between 2004 and 2017, organic amendments (sheep manure) were reduced by 50%, crop rotation was intensified, and green fertilization and forage maize cultivation were included. As a result, P3 showed an improvement in comparison with P2, with decreases in EC (1.4 dS m−1), exchangeable Na (0.2 g kg−1), and TN (0.8 g kg−1). The change in soil management enhanced some soil functions (carbon sink and chemical fertility) and attenuated soil degradation. [ABSTRACT FROM AUTHOR]

To advance our understanding of land-atmosphere exchanges of water, energy and carbon dioxide (CO2) in space and time over heterogeneous land surfaces, two intensive field campaigns were carried out at the Barrax agricultural test site in Spain during 12-21 July 2004 (SPARC 2004) and 8-14 July 2005 (SEN2FLEX 2005) involving multiple field, satellite and airborne instruments for characterizing the state of the atmosphere, the vegetation and the soil from the visible to the microwave range of the spectrum. Part of the experimental area is a core site of area 25 km2, within which numerous crops are grown, on both irrigated and dry land, alongside fields of bare soil. The campaigns were carried out in the framework of the Earth Observation Envelope Programme of the European Space Agency (ESA) with the aim of supporting geophysical algorithm development, calibration/validation and the simulation of future spaceborne Earth Observation missions. Both campaigns were also contributions to the EU 6FP EAGLE Project. The emphasis of this contribution is on the in situ measurements of land-atmosphere exchanges of water, energy and CO2 as well as the thermal dynamic states of the atmosphere, the soil and the vegetation. Preliminary analysis and interpretation of the measurements are presented. These two data sets are open to the scientific community for collaborative investigations. [ABSTRACT FROM AUTHOR]

The article assesses the extent and causes of erosion and terrace failure on abandoned fields and options for mitigation in the Careavo basin, a semi-arid catchment in southeast Spain. According to the study that At catchment scale all abandoned fields were surveyed and characteristics of each field were described. In addition, researchers surveyed abandoned and cultivated terraces and used statistical analyses to determine the factors that induce terrace failure. At field scale the researchers constructed a detailed digital elevation model (DEM) for an abandoned terrace field o calculate sediment losses since time of abandonment.

Abstract: A laboratory experiment involving the use of leaching columns reproducing the topmost portion of a Hyperdystric Acrisol (FAO 1998) or plinthic Palexerult (Soil Survey Staff 2003) treated in its Ap horizon with sugar foam wastes and phosphogypsum was conducted. The amendments increased the contents in exchangeable calcium (Ca) of the Ap horizon and, to a lesser extent, also that of the AB horizon. However, the contents in exchangeable magnesium (Mg) and sodium (Na) decreased as much in Ap as they did in AB; by contrast, the potassium (K) content exhibited a less marked decrease. The potassium chloride (KCl)-extractable aluminium (Al) of the Ap horizon was dramatically decreased much more than that of the AB horizon by the amendments. In the soil solution from Ap, the amendments raised the pH and decreased the Al concentration; in that from AB, however, they caused an initial pH decrease, a tendency that reversed as the gypsum was leached and eventually led to the pH exceeding that in the soil solution from control. The first few water extractions exhibited increased Mg concentration. This trend was reversed in the second leaching cycle, where the concentrations of Mg in the amended columns were lower than those in the controls. In the soil solution, the variation of the Ca and sulphate (SO4 2-) concentrations was influenced by the salt-sorption effect. The total Al content in soil solution from AB increased during the first leaching cycle and then decreased during the second. The amendments decreased the activities of Al3+, AlOH+2, and Al(OH)2 + in the Ap horizon and increased those of Al3+, AlSO4 +, Al(SO4)2 -, and AlF+2 in the first leaching cycle in the AB horizon. The productivity of the Ap horizon after the treatments was assessed using a wheat crop (T. aestivum, var. 'Jabato') in a greenhouse. [ABSTRACT FROM AUTHOR]

This study characterizes the soil types on which natural stands of Quercus robur L. grow in northwest Spain. Nineteen edaphic parameters were obtained from the data collected in the sampling of 39 oak soils. Siliceous substrates were present in all of the stands, with granite and schist substrates being dominant. The soils on which the stands were grown were mainly Dystric cambisols. The values of the parameters that reflect the main chemical and biological soil properties [pH, organic matter, nitrogen (N), and carbon (C)/N ratio] were similar to the values considered optimal for these formations by other researchers. The exception was the values obtained for organic matter, which were slightly higher. The concentrations of nutrients in these soils were considered relatively low or medium as compared with the concentration of nutrients in soils under pine and eucalyptus forests in the study area, except phosphorus, which was considerably higher. [ABSTRACT FROM AUTHOR]

This study evaluates soil properties in organically managed olive groves and natural zones in a mountainous area of Andalusia, Spain. Two soil types (Eutric Regosol and Eutric Cambisol) and the most common soil management methods (tillage and two intensities of grazing) were studied. Both soil types in the groves had values not much lower than those in the natural areas. Average (±SE) values in the groves were 1.58 ± 0.71% for organic carbon, 323 ± 98 g kg−1 for macroaggregate stability, 1.11 ± 0.16 g cm−3 for bulk density, 3.5 ± 1.6 mm h−1 for saturated hydraulic conductivity and 1209 ± 716 mg CO2 kg−1 for soil respiration. Overall, these values tended to be lower in the tilled compared with that in the grazed groves. The average phosphorus soil content (5.83 ± 5.22 mg kg−1) was low for olive production and within adequate ranges for N (0.12 ± 0.05%) and K (142 ± 81 mg kg−1). Soil erosion was high in the tilled groves (35.5 ± 18.2 t ha−1 year−1) with soil loss correlating with indicators of soil degradation such as organic carbon content and water stable macroaggregates. In the grazed groves, soil loss was moderate with no clear indications of soil degradation. Overall, there was significant farm-to-farm variability within the same soil and land management systems. Olive production had a moderate effect on soil degradation compared with natural areas and olive cultivation could be sustained in future if cover crop soil management replaced tillage, especially in the most sloping areas. [ABSTRACT FROM AUTHOR]