In situ net N mineralisation and nitrification under organic and conventionally managed olive oil orchards

Olive oil orchard occupies a great percentage of the cropland in southern Spain. Thus, changes in nitrogen (N) fertilization might have a great effect on N dynamics at least at regional scale, which should be investigated for a sustainable N fertilization program. In situ net N mineralization (NM) and nitrification (NN) were investigated during a year in comparable organic (OR) and conventional (CV) olive oil orchards of two locations differing their N input. Soil samples were collected in two soil positions (under and between trees canopy) and both buried-bags and soil core techniques were used to quantify both microbial rates. There were differences in NM and NN between sites mainly due to differences in soil total N (TN), and potential mineralisable N (PMN). In all cases NM and NN were higher in soils under tree canopy. NM and NN were higher in OR than in CV managed orchards in the location with high soil TN. Soil TN and PMN explained together a 50 % of the variability in soil N availability, which suggests that these two variables are good predictors of the potential of a soil to provide available N. The highest rates of soil N availability were found in spring, when olive tree demand for N was at its maximum. Annual soil N availability in olive groves was in all cases higher or similar than tree demand suggesting that soil annual supply of N should be taken into account in order to develop sustainable N fertilisation strategies for olive crops

Linking biogeochemical variability and microbial community structure in forest soils: Abies pinsapo-fir forests as a study case

Tradicionalmente, los estudios biogeoquímicos consideraban el suelo como una "caja negra", conectada con el resto del ecosistema mediante flujos de entrada y de salida de nutrientes, en la que éstos experimentan transformaciones mediadas en gran parte por microorganismos desconocidos. El desarrollo de nuevas técnicas moleculares ha incrementado el conocimiento sobre las comunidades microbianas del suelo. Estudios recientes han puesto de manifiesto correspondencias entre la variabilidad de la disponibilidad de nutrientes y la estructura de la comunidad microbiana en suelos forestales. A este respecto, hemos empleado bosques de Abies pinsapo como modelo ya que muestran una gran variabilidad biogeoquímica asociada a diferencias litológicas y sucesionales, mientras que la estacionalidad mediterránea provoca una alta variabilidad intra anual en la disponibilidad de nutrientes. Además, existen pinsapares sujetos a limitación o a saturación de nitrógeno. Mediante análisis del polimorfismo de longitud de fragmentos de restricción terminal (T-RFLP), hemos puesto de manifiesto que los patrones de variabilidad biogeoquímica descritos en los pinsapares se corresponden con cambios en la composición y estructura de sus comunidades bacterianas.Traditionally, soil has been considered as a "black box", connected to the rest of the ecosystem by input and output fluxes, where nutrients are transformed mainly through processes controlled by unknown microorganisms. The development of new molecular techniques has increased our knowledge about microbiological soil communities. Recent studies reveal that change in nutrient availability in forest soils is associated with shifts in the soil community structure. We have used Abies pinsapo fir forests as a model case to this regard, since they show a marked among-sites biogeochemical variability due to changes in lithology and successional status, while Mediterranean seasonality determines high intra-year variability in nutrients availability. Moreover, A. pinsapo forests that are either N-limited or N-saturated do exist. Using terminal restriction fragments length polymorphism (T-RFLP) analysis we have demonstrated that these patterns of biogeochemical variability are associated with shifts in the structure of the soil bacterial communities

Estimación de la cobertura vegetal en matorrales semiáridos mediante el uso de drones tras una quema prescrita. Validación mediante datos de campo

Este trabajo se ha desarrollado en el marco del proyecto Open2preserve (SOE2/P5/E0804) financiado por el Programa Interreg Sudoe. Asimismo ha recibido financiación del MICINN a través del Fondo Europeo de Desarrollo Regional [SUMHAL, LIFEWATCH-2019-09-CSIC-13, POPE 2014-2020]

Data from: Shrub encroachment can reverse desertification in semi-arid Mediterranean grasslands

The worldwide phenomenon of shrub encroachment in grass-dominated dryland ecosystems is commonly associated with desertification. Studies of the purported desertification effects associated with shrub encroachment are often restricted to relatively few study areas, and document a narrow range of possible impacts upon biota and ecosystem processes. We conducted a study in degraded Mediterranean grasslands dominated by Stipa tenacissima to simultaneously evaluate the effects of shrub encroachment on the structure and composition of multiple biotic community components, and on various indicators of ecosystem function. Shrub encroachment enhanced vascular plant richness, biomass of fungi, actinomycetes and other bacteria, and was linked with greater soil fertility and N mineralization rates. While shrub encroachment may be a widespread phenomenon in drylands, an interpretation that this is an expression of desertification is not universal. Our results suggest that shrub establishment may be an important step in the reversal of desertification processes in the Mediterranean region

Data from: Shrub encroachment can reverse desertification in semi-arid Mediterranean grasslands

The worldwide phenomenon of shrub encroachment in grass-dominated dryland ecosystems is commonly associated with desertification. Studies of the purported desertification effects associated with shrub encroachment are often restricted to relatively few study areas, and document a narrow range of possible impacts upon biota and ecosystem processes. We conducted a study in degraded Mediterranean grasslands dominated by Stipa tenacissima to simultaneously evaluate the effects of shrub encroachment on the structure and composition of multiple biotic community components, and on various indicators of ecosystem function. Shrub encroachment enhanced vascular plant richness, biomass of fungi, actinomycetes and other bacteria, and was linked with greater soil fertility and N mineralization rates. While shrub encroachment may be a widespread phenomenon in drylands, an interpretation that this is an expression of desertification is not universal. Our results suggest that shrub establishment may be an important step in the reversal of desertification processes in the Mediterranean region

Granulocyte–monocyte apheresis: an alternative combination therapy after loss of response to anti-TNF agents in ulcerative colitis

[Objective] To evaluate the effectiveness and safety of the combination of granulocyte–monocyte apheresis (GMA) after loss of response (LOR) to anti-tumor necrosis factor (TNF) agents in ulcerative colitis (UC).[Materials and methods] A retrospective, multicenter study was performed in 11 inflammatory bowel disease (IBD) Units. Clinical remission was defined as a partial Mayo score ≤2. The effectiveness of the treatment was evaluated by the partial Mayo score and the rate of anti-TNF intensification, switch, swap or colectomy.[Results] Forty-seven patients with ulcerative colitis were included (mean age 35 years, mean disease duration 52 months, 66% male and 59% extensive colitis). Twenty-three subjects were receiving infliximab, eighteen adalimumab and six golimumab. GMA was combined after a primary non-response (49%) or secondary loss of response (51%) to anti-TNF therapy. We observed a significant decrease in partial Mayo score and fecal calprotectin after GMA. Fifteen patients (32%) responded to the combination therapy without anti-TNF intensification, switch, swap or colectomy. Eight patients (17%) underwent colectomy. Two patients (4%) presented adverse events related to the technique.[Conclusions] Combination of GMA and anti-tumor necrosis factor is a safe and effective treatment after the loss of response to these biologic agents, with a significant decrease of the clinical disease activity and biomarkers, in a population with limited therapeutic alternatives

Environmental and soil data from encroached/unencroached Stipa tenacissima steppes from Spain

Environmental (coordinates, elevation, slope, aspect, mean annual rainfall and temperature) and soil (pH, organic carbon, total nitrogen, total phosphorus, soil respiration, potassium and nitrogen mineralization) variables at the microsite and site scales for Stipa tenacissima grasslands with and without sprouting shrubs in a gradient from central to southern Spain

Post-fire soil functionality and microbial community structure in a Mediterranean shrubland subjected to experimental drought

Fire may cause significant alterations in soil properties. Post-fire soil dynamics can vary depending, among other factors, on rainfall patterns. However, little is known regarding variations in response to post-fire drought. This is relevant in arid and semiarid areas with poor soils, like much of the western Mediterranean. Furthermore, climate change projections in such areas anticipate reduced precipitation and longer annual drought periods, together with an increase in fire severity and frequency. This research evaluates the effects of experimental drought after fire on soil dynamics of a Cistus-Erica shrubland (Central Spain). A replicated (n = 4) field experiment was conducted in which the total rainfall and its patterns were manipulated by means of a rain-out shelters and irrigation system. The treatments were: environmental control (natural rainfall), historical control (average rainfall, 2. months drought), moderate drought (25% reduction of historical control, 5. months drought) and severe drought (45% reduction, 7. months drought). After one growing season under these rainfall treatments, the plots were burned. One set of unburned plots under natural rainfall served as an additional control. Soils were collected seasonally. Fire increased soil P and N availability. Post-fire drought treatments reduced available soil P but increased N concentration (mainly nitrate). Fire reduced available K irrespective of drought treatments. Fire reduced enzyme activities and carbon mineralization rate, a reduction that was higher in post-fire drought-treated soils. Fire decreased soil microbial biomass and the proportion of fungi, while that of actinomycetes increased. Post-fire drought decreased soil total microbial biomass and fungi, with bacteria becoming more abundant. Our results support that increasing drought after fire could compromise the resilience of Mediterranean ecosystems to fire