Effects of herbaceous covers and mineral fertilizers on the nutrient stocks and fluxes in a Mediterranean olive grove

The preservation of nutrient capital, soil fertility, and carbon (C) sequestration capacity in Mediterranean olive groves requires evaluation of agricultural practices beyond short-term productivity. We aim to contribute with a mechanistic understanding on the effects that the preservation of herbaceous cover and the use of chemical fertilizers have on the performance of olive trees and on the biogeochemical cycles of the agroecosystem. We compared nutrient fluxes and aboveground leafy stocks in an olive grove that had been organically managed for more than 60 years, in a treatment in which the annual spontaneous herbaceous cover was maintained (H), and after two years of shift to conventional management treatments in which the growth of herbaceous vegetation was avoided by the use of herbicides (NH), and where exclusion of the herbaceous cover is also combined with the supply of mineral fertilizers (NHF). Maintenance of herbaceous vegetation in H contributed to the retention of a high aboveground capital of C and nutrients, particularly nitrogen, (N), phosphorus (P) and potassium (K) that were about 2.9, 3.9 and 7.4 times greater than in NH, respectively. The permanence of herbaceous cover stimulated olive tree leaf litter decomposition rates by about 86 % and increased nutrient release. However, the H treatment led to a 37 % decrease in olive yield and lowered olive foliar N and P content as negative short-term effects. The addition of fertilizers (N, P, K, and Mg) in mineral and solid form in NHF resulted inefficient to improve olive tree nutritional status and olive production, and decelerated olive tree litter decomposition rates by 21 % and nutrient release. The nutrient retention in organic forms in the fast-growing species of herbaceous covers and the progressive nutrient release as litter decomposes may contribute to regulate and better adapt nutrient availability to the nutrient requirements of olive trees.European CommissionMinistry of Economy, Innovation, Science and Employment of the Junta de Andalucia (Andalucia Talent Hub Program, Marie Sklodowska-Curie actions, COFUND) 291780European Union Horizon 2020 research and innovation program under the Marie Sklodowska-Curie fellowship "StoiCa" 750252Spanish GovernmentERDF funds-"ELEMENTAL" CGL2017-83538-C3-1-R ERDF funds-"INTEGRATYON3" PID2020-117825GB-C21Serra Hunter fellowship Programme from the regional Government of CataloniaJuan de la Cierva postdoctoral contracts - MCIN/AEI FJC2018-038192-I IJC2020-045630-IEuropean Union NextGenerationEU/PRTRMCIN/AEI MdM-2017-0714HIPATIAUAL postdoctoral fellowship - University of Almeri

Tratamiento de depósitos electroforéticos de YBa2Cu3O7 sobre substratos policristalinos mediante fusión zonal por láser

[EN] Obtaining coatings on metallic substrates of irregular geometries is not easy by traditional methods. In those cases electrochemical methods show important advantages and have been used successfully. To date only silver has shown to be inert with respect to superconducting cuprates, although progress has been made in the development of intermediate buffer layers. However, in the particular case of YBa2Cu3O7 , annealing above the cuprate superconducting melting point to attempt densification or texturing is hard on silver because of the lower melting point of the metal. . Focalized heating of superconducting oxides over metallic substrates, using LASER techniques on controlled geometries, allows densification of coatings. The Laser processed sample may be amorphous but the crystallinity is easily recovered, as well as the optimal oxygen content for the oxide, but the preferential orientation induced by the electrophoretic deposition is lost upon the recrystallization process occurring over polycrystaline substrates.[ES] La realización de depósitos de óxidos superconductores sobre substratos metálicos de geometría compleja y en general policristalinos está prácticamente basada en métodos electroforéticos o electroquímicos que permiten la utilización de un campo eléctrico de geometría definida para inducir el movimiento de partículas de óxido o de precursores de éste, hacia el electrodo elegido. Dichos métodos son fundamentales cuando el substrato es metálico o puede hacerse metálico con facilidad. Hasta el presente tan sólo la plata ha mostrado ser lo suficientemente inerte para permitir recocidos posteriores, aunque se está progresando en el desarrollo de capas “buffer”. Sin embargo, cuando el óxido depositado es YBa2Cu3O7 , el proceso de recocido posterior no permite la obtención de textura sobre Ag mediante métodos térmicos dado el inferior punto de fusión de este metal. El presente trabajo presenta un estudio de fusión zonal por láser que permite recocer el óxido sin fundir el substrato metálico de plata. El control de las distintas variables permite llegar a una solución en la que se puede preservar la naturaleza superconductora del depósito y su densificación. Ello requiere un tratamiento térmico posterior que recupera la cristalinidad y el contenido óptimo de oxígeno. Sin embargo, el tratamiento disminuye la orientación preferencial de las partículas de YBa2Cu3O7 que se obtiene mediante la deposición electroforética.The authors want to thank the Spanish Ministery of Culture (former Science and Education) for financing through grants CICYT MAT96-1057-c02-01, PB98-0491 and graduate fellowships, and REE for the contract CSIC-REE on 1997- 1998.Peer reviewe

Effects of herbaceous covers and mineral fertilizers on the nutrient stocks and fluxes in a Mediterranean olive grove

Altres ajuts: acord transformatiu CRUE-CSICThe preservation of nutrient capital, soil fertility, and carbon (C) sequestration capacity in Mediterranean olive groves requires evaluation of agricultural practices beyond short-term productivity. We aim to contribute with a mechanistic understanding on the effects that the preservation of herbaceous cover and the use of chemical fertilizers have on the performance of olive trees and on the biogeochemical cycles of the agroecosystem. We compared nutrient fluxes and aboveground leafy stocks in an olive grove that had been organically managed for more than 60 years, in a treatment in which the annual spontaneous herbaceous cover was maintained (H), and after two years of shift to conventional management treatments in which the growth of herbaceous vegetation was avoided by the use of herbicides (NH), and where exclusion of the herbaceous cover is also combined with the supply of mineral fertilizers (NHF). Maintenance of herbaceous vegetation in H contributed to the retention of a high aboveground capital of C and nutrients, particularly nitrogen, (N), phosphorus (P) and potassium (K) that were about 2.9, 3.9 and 7.4 times greater than in NH, respectively. The permanence of herbaceous cover stimulated olive tree leaf litter decomposition rates by about 86 % and increased nutrient release. However, the H treatment led to a 37 % decrease in olive yield and lowered olive foliar N and P content as negative short-term effects. The addition of fertilizers (N, P, K, and Mg) in mineral and solid form in NHF resulted inefficient to improve olive tree nutritional status and olive production, and decelerated olive tree litter decomposition rates by 21 % and nutrient release. The nutrient retention in organic forms in the fast-growing species of herbaceous covers and the progressive nutrient release as litter decomposes may contribute to regulate and better adapt nutrient availability to the nutrient requirements of olive trees

International lower limb collaborative (INTELLECT) study: a multicentre, international retrospective audit of lower extremity open fractures

Trauma remains a major cause of mortality and disability across the world1, with a higher burden in developing nations2. Open lower extremity injuries are devastating events from a physical3, mental health4, and socioeconomic5 standpoint. The potential sequelae, including risk of chronic infection and amputation, can lead to delayed recovery and major disability6. This international study aimed to describe global disparities, timely intervention, guideline-directed care, and economic aspects of open lower limb injuries

Electrochemical oxidation of La2CuO4. Phase equilibria among superconductors

Electrochemical oxidation of La2CuO4 in aqueous OHMIN yield superconducting materials with Tc values that depend on the degree of oxidation and the temperature. The chemical nature of the charge carriers changes with temperature, yielding notable changes in Tc values. For the maximum oxidation of 0.15 holes per copper, an internal redistribution of holes between Cu and O is proposed from RT to 100 °C. Partial derivatives of magnetic susceptibility vs susceptibility show the existence of several coexisting phases with distinct Tc's, possibly within each grain.Peer Reviewe

Superconducting YBa2Cu3O7-δ deposits by electrodeposition in complexing media

This work describes the obtention of YBa2Cu3O7-δ deposits over metallic wires by electrodeposition of metallic precusors from DMSO solutions at constant potential and thermal treatment in oxidizing atmospheres. Simultaneous deposition of Cu, Y and Ba is achieved by reacting copper ions with complexing agents. In this way copper may be deposited at potentials near those of Y and Ba, and thus, we avoid the expected problems of preferential deposition for copper. After annealing, the deposits show bulk superconducting properties with Tc values of 92K, and significant grain conection. Particle sizes are {reversed tilde} 10μm. Small impurities of Y2BaCuO5 and CuO are found by Xray diffraction and electron microscopy. Codeposition of K is also observed, but the final product does not contain detectable amounts of this element.Financed by the MIDAS progcam (Red EIéctrica-CICYT)Peer Reviewe

Superconducting YBa2Cu3O7-δ coatings by simultaneous electrodeposition of Y, Ba, and Cu in the presence of cyanide

Simultaneous deposition in nonaqueous media (dimethyl sulfoxide) of Y, Ba, and Cu was achieved by electrolysis at constant potential in the presence of cyanide ions. Cyanide lowers the reduction potential for Cu to values near the reduction potentials for Y and Ba. Thus, an Y-Ba-Cu precursor is formed in situ over silver substrates, which upon an appropriate thermal treatment yields a YBa2Cu3O7-δ coating; further annealing in oxygen renders the material superconducting. Depending on the substrate, the complexing agent, additives, and Y:Ba:Cu stoichiometric ratios in the bath, several impurities are detected. For the best deposits obtained, Y2BaCuO5 and CuO are present in small amounts. Potassium gets deposited along with Y, Ba, and Cu, but the oxidizing thermal treatment yields a coating with no traces of potassium present. After the thermal processing, the wires obtained present bulk superconducting properties. The particle size of YBa2Cu3O7-δ in the final coating is about 10 μm. Intergranular connection is notable although the critical intergranular field is below 10 G. Tc values found are 92 K, the highest reported for YBa2Cu3O7-δ prepared by this method on metallic substrates. Typical superconducting fractions are about 60%, and Jc values at liquid nitrogen temperatures are 51 A/cm2 for deposits 96 μm thick over Ag substrates.This work has been financed by the MIDAS Program (CICYT-Red Eléctrica de España, Grants 9211592 and 93123311, and the Spanish Ministery of Education and Science (CICYT, Grant MAT 93-0240-C04-01)Peer Reviewe

Obtention of superconducting YBa2Cu3O7-δ deposits by electrodeposition and electrophoresis

Simultaneous electrodeposition of Y, Ba and Cu from solution is achieved in presence of complexing agents, using metal wires as substrates. The resulting wire is superconducting after thermal treatment at 900 °C. The main problem is the presence of excess copper in the deposit that may be easily overcome using cyanide as a complexing agent which inhibits copper deposition in DMSO. On the other hand, deposition of YBa2Cu3O7-δ particles by electrophoresis yields superconducting wires with preferential orientation and high critical currents.Peer Reviewe