[ES] En esta tesis doctoral se discuten una serie de cuestiones científicas relacionadas con a la producción y el procesamiento de algunas especies de cítricos de especial relevancia en Sicilia y en el área mediterránea. Los objetivos se centran en estudiar la trazabilidad y sostenibilidad de la producción de algunas especies de cítricos, así como encontrar nuevas aplicaciones a los subproductos y productos de desecho de la industria, con el fin de mejorar su rentabilidad. Por lo tanto, los temas que se desarrollarán serán los siguientes: caracterización de los compuestos bioactivos presentes en aceites esenciales y en el hidrolato de diferentes especies de cítricos; seguimiento del efecto del estrés hídrico controlado sobre la producción de aceites esenciales en hojas y flores del cv. Sanguinelli de Citrus sinensis y del cv. Clemenules de Citrus reticulata; estudio de los efectos fitotóxicos de los aceites esenciales en cuatro especies arvenses importantes en el área mediterránea, dos monocotiledóneas (Echinochloa crus-galli (L.) P.Beauv. y Avena fatua L.) y dos dicotiledóneas (Amaranthus retroflexus L. y Portulaca oleracea L.) mediante experimentos in vitro e in vivo; estudio del efecto bioestimulantes de las aguas residuales de la industria procesadora de cítricos sobre la comunidad microbiana del suelo; cuantificación de elementos de tierras raras en frutos de limón cultivados en diferentes áreas geográficas, para su posible uso como trazador geoquímico. Los principales resultados obtenidos son la caracterización de diferentes aceites esenciales, de los cuales los producidos por los residuos de la poda podrían ser utilizados como método de extracción de nuevos aceites esenciales con alto rendimiento. También se han encontrado sustancias nutracéuticas y farmacológicas en los hidrolatos industriales de naranja. Por otra parte, el aceite esencial industrial de limón mostró un buen potencial como agente herbicida, siendo, por tanto, de gran interés en la fabricación de herbicidas de origen natural, biodegradables y ecológicos. La aplicación del estrés hídrico controlado después del reposo invernal y, por tanto, en el momento de la brotación incrementó el diámetro final del fruto. La respuesta en el árbol no fue inmediata. La aplicación de hidrolatos de limón, naranja y mandarina al suelo junto al agua de riego, potenció los depósitos de C contribuyendo a aumentar la biomasa y mejoró la actividad microbiana. Estos resultados ponen de manifiesto el papel que los hidrolatos pueden desempeñar en la agricultura sostenible mejorando la fertilidad del suelo. Finalmente, el modelo de elementos de tierras raras podría utilizarse como una herramienta de conexión entre la producción de limón y el suelo del que proviene, contribuyendo, de esta manera, a su caracterización geográfica. En resumen, los resultados obtenidos en esta tesis contribuyen a impulsar el sector cítrico siciliano ya que: proporcionan medios para una agricultura sostenible; aumentan el valor de los subproductos y residuos de la industria; proponen aplicaciones para que el ciclo de producción y transformación sea más rentable y revalorizan los limones sicilianos vinculándolos a su zona de producción. / [CA] En esta tesi doctoral es discutixen una sèrie de qüestions científiques relacionades amb la producció i el processament d'algunes espècies de cítrics d'especial rellevància a Sicília i a l'àrea mediterrània. Els objectius, acordats prèviament amb la indústria de cítrics "EuroFood" i finançats pel projecte d'investigació "PON Industrial Ph.D. - a.a. 2016/2017", es centren en estudiar la traçabilitat i sostenibilitat de la producció d'algunes espècies de cítrics, així com de trobar noves aplicacions als subproductes i productes de rebuig de la indústria, amb el fi de millorar la seua rentabilitat. Per tant, els temes que es desenvoluparan seran els següents: caracterització dels compostos bioactius presents en els olis essencials i en el l'hidrolato de diferents espècies de cítrics; seguiment de l'efecte de l'estrés hídric controlat en la producció d'olis essencials en fulles i flors del cv. Sanguinelli de Citrus sinensis i del cv. Clemenules de Citrus reticulata; estudi dels efectes fitotòxicos dels olis essencials de cítrics en quatre espècies arvenses importants en l'àrea mediterrània, dos monocotiledònies (Echinochloa crus-galli (L.) P.Beauv. i Avena fàtua L.) i dos dicotiledònies (Amaranthus retroflexus L. i Portulaca oleracea L.) per mitjà de diferents experiments in vitro i in vivo; estudi de l'efecte bioestimulant de les aigües residuals de la indústria processadora de cítrics sobre la comunitat microbiana del sòl; quantificació d'elements de terres rares en fruits de llima cultivats en diferents àrees geogràfiques, per al seu possible ús com a traçador geoquímic. Els principals resultats obtinguts són la caracterització de diferents olis essencials, dels quals els produïts pels residus de la poda podrien ser utilitzats com a mètode d'extracció de nous olis essencials amb alt rendiment. També s'han trobat substàncies nutracéutiques i farmacològiques en els hidrolats industrials de taronja. D'altra banda, l'oli essencial industrial de llima va mostrar un bon potencial com a agent herbicida, sent, per tant, de gran interés en la fabricació d'herbicides d'origen natural, biodegradables i ecològics. L'aplicació de l'estrés hídric controlat després del repòs hivernal i, per tant, en el moment de la brotació va incrementar el diàmetre final del fruit. La resposta en l'arbre no va ser immediata. L'aplicació de hidrolats de llima, taronja i mandarina al sòl amb l'aigua de reg, va augmentar els depòsits de carbó (C) contribuint a augmentar la biomassa i va millorar l'activitat microbiana. Aquests resultats posen de manifest el paper dels hidrolats en l'agricultura sostenible millorant, d'aquesta manera, la fertilitat del sòl. Finalment, el model d'elements de terres rares podria utilitzar-se com una ferramenta d'enllaç entre la producció de llima i el sòl del què prové, contribuint, d'esta manera, a la seua caracterització geogràfica. En resum, els resultats obtinguts en esta tesi doctoral contribueixen a impulsar el sector cítric sicilià ja que: - proporcionen mitjans per a una agricultura sostenible; - augmenten el valor dels subproductes i residus de la indústria; - proposen aplicacions perquè el cicle de producció i transformació siga de més rendabilitat; - revaloritzen les llimes d'origen sicilià vinculant-les a la seua zona de producció. / [EN] In this doctoral thesis are discussed a series of scientific issues regarding citrus fruits production and processing, species of particular relevance in Sicily and in the Mediterranean area. Objectives and research activities addressed in this thesis were agreed with the citrus industry "EuroFood" and financed by the research project "PON industrial Ph.D. - a.a. 2016/2017". The research project was targeted to study the traceability and sustainability of citrus production, and to find new applications to the by-products and waste products of citrus industry with the objective of appreciate and enhance the Sicilian citrus industry. The following topics are addressed and developed in this thesis: - Characterization of the bioactive compounds present in essential oils (EOs) and in the hydrolate of different citrus species. - Monitoring of the effect of controlled water stress on the production of EOs in leaves and flowers of Citrus sinensis (L.) Osbeck cv. 'Sanguinelli' and Citrus reticulata Blanco cv. 'Clemenules'; -Test the phytotoxic effects of citrus EOs on four important weed species in the Mediterranean area, two monocotyledon (Echinochloa crus-galli (L.) P.Beauv. and Avena fatua L.) and two dicotyledon (Amaranthus retroflexus L., and Portulaca oleraceaL.) by different experiments in vitro and in greenhouse conditions; -Evaluation of the effect as natural biostimulants of wastewaters from citrus processing industry by its application on soil microbial community; -Quantification of rare earth elements in lemon fruits from different geographical areas for its possible use as geochemical tracers applied to lemon production. Different Citrus EOs have been characterized in this study and it has been verified that the oils produced by the pruning waste could be used for the extraction of EOs with high yields. In addition, nutraceutical and pharmacological substances have been found in the orange industrial hydrolates. Industrial lemon EO showed good potential when testing its herbicidal activity. Lemon EO represents a good basis for the development of herbicides of natural origin, biodegradable and eco-friendly. Thanks to the application of water stress after the winter vegetative restart, a conclusion found was that water stress increased the diameter of the fruit and it was observed that the effects of stress were not immediate on citrus trees, but were evident after some time. The study of the application of lemon, orange and mandarin hydrolates in the soil, as irrigation water provided the effects on stable and labile soil C pools, on biomass and microbial activity and on main microbial groups. Overall, hydrolates can play a role in sustainable agriculture because when added to a soil, they improve soil quality and fertility. The Rare Earth Element model could be used as a tool to connect lemon production to the soil where they were produced, for a possible geographical characterization and a direct link between the production and the territory or soil. The results obtained were very interesting because: - they provided the means for sustainable agriculture; - they increased the value of the by-products and waste products of the citrus industry; - they proposed applications for the citrus production and transformation cycle being more sustainable; - they could valorize the Sicilian lemons by linking them to their production area. These results could have practical repercussions in the production cycle of citrus fruits and give a boost to the Sicilian citrus fruit sector. / Objectives and research activities addressed in this thesis were agreed with the citrus industry "EuroFood" and financed by the research project PON industrial Ph.D. - a.a. 2016/2017 / Ioppolo, A. (2020). Valorization of Citrus spp. Cultivars cultivated in Sicily for the industrial use of citrus derivatives and in particular for potential alternative uses of essential oils for the enhancement of the island's citrus production [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159385 / TESIS

This study is the first to consider how the combination of root physical effects, microbial production of EPS, and root effects on the hydrodynamic boundary layer could influence streambank soil erodibility. Specifically, the goal of this research was to quantify the physical and biological effects of roots on streambank fluvial erosion. A series of laboratory-scale erosion tests were conducted using a mini jet erosion testing device and a recirculating flume channel to address this goal. Several soil and vegetation factors that influence fluvial entrainment, like extracellular polymeric substances (EPS), soil aggregate stability and root length density, were measured following erosion testing. For flume experiments, three streambank boundary conditions were constructed to simulate unvegetated streambanks, as well as streambanks with herbaceous and woody roots. Soil treatments were also created to represent unamended and organic matter (OM) amended soil either without roots (bare soil), with synthetic roots, or with living roots (Panicum virgatum). Median soil erosion rates along the simulated rooted boundaries were two to ten times higher compared to the unvegetated boundary due to protruding root impacts on the boundary layer. In flume experiments, median erosion rates were 30% to 72% lower for unamended soils containing compacted synthetic root fibers as compared to bare soil samples. Adding both OM and fibers to the soil had a greater effect; the median erosion rate reductions of live rooted treatments (95% to 100%) and synthetic rooted + OM treatments (86% to 100%) were similar and statistically lower than bare soil controls. Stimulated microbial production of EPS proteins were significantly correlated with increased erosion resistance in OM-amended treatments while OM treatments had significantly lower EPS carbohydrates compared to unamended treatments. In summary, while sparsely spaced roots exposed on streambanks may increase soil erosion rates due to impacts on the hydrodynamic boundary layer, overall results highlight how the synergistic relationship between root fibers and soil microbes can significantly reduce streambank soil erodibility due to fiber reinforcement and EPS production. / Doctor of Philosophy / Plant roots are known to protect streambank soils from erosion by water; however, exactly how roots provide this protection has remained unclear. Among other things, roots can influence streambank soil erosion by holding soil together through a thick root network, interacting with soil microorganisms to stimulate the release of "sticky" organic compounds called extracellular polymeric substances (EPS), and altering the force of the water against the streambank. This research aimed to quantify and compare the relative importance of these three mechanisms on streambank soil erosion using a mini jet erosion testing device and an indoor recirculating flume channel. To do this in the flume, three walls were constructed to simulate unvegetated streambanks, as well as streambanks with herbaceous and woody roots. In greenhouse settings, soil treatments were also created to represent unamended and organic matter (OM) amended soil either without roots (bare soil), with artificial roots, or with living roots (Panicum virgatum). While roots protruding out of streambanks appeared to increase median soil erosion rates due to the impact of roots on near-bank flow, artificial roots in the soil and OM amended soils reduced soil erosion rates. Specifically, OM amendments stimulated the production of EPS proteins, leading to improved soil stability and increased soil resistance to erosion by water. Overall results highlight how the synergistic relationship between root fibers (living roots and artificial roots) and soil microbes can significantly reduce streambank soil erodibility due to root binding and microbial production of EPS. While plant roots naturally provide both fibers and EPS to soils, these materials could be incorporated into fill soils during construction to rapidly increase soil erosion resistance following levee construction and stream restoration projects.

Herbicides have become a key component in modern agricultural production. Meanwhile, there is a concern that some herbicides persist past the growing season of the treated crop, and negatively influence the production of the subsequently planted crops. Amongst various herbicides used in western Canada, acetohydroxyacid synthase (AHAS)-inhibiting herbicides warrant special attention given their residual properties and acute plant toxicity at low concentrations in soil. Soil residual AHAS inhibitors have the potential to influence both leguminous host plants and their bacterial symbiotic partners; consequently, the use of an AHAS inhibitor in a given year can negatively influence the inoculation success and grain yield of legumes cropped in the following year. <p>The present thesis project focused on one of the AHAS inhibiting herbicides (flucarbazone) and studied its potential for carryover injury and negative influence on the success of inoculation in field pea. A series of growth chamber and field experiments were conducted to test the following null hypothesis: the presence of residual flucarbazone in soil does not affect nodulation of field pea by inoculum rhizobia. <p>A growth chamber experiment clearly demonstrated the susceptibility of field pea to the presence of flucarbazone in soil where the lowest concentration of flucarbazone amendment (5 ìg kg1) significantly reduced the crop growth. In contrast, a field study failed to reveal any negative effects of flucarbazone use on crop growth and N2 fixation. <p>It was concluded that if the weather and soil conditions favour decomposition of flucarbazone as described in the present study, flucarbazone applied at the recommended field rate will not persist into the following season at high enough concentrations to negatively influence field pea growth, grain yields, and inoculation success. To ensure safety of rotational crops, it is important to strictly adhere to the herbicide application guidelines. Additionally, producers are cautioned to be particularly aware of the environmental and soil conditions that may reduce the rate of herbicide degradation.

Herbicides have become a key component in modern agricultural production. Meanwhile, there is a concern that some herbicides persist past the growing season of the treated crop, and negatively influence the production of the subsequently planted crops. Amongst various herbicides used in western Canada, acetohydroxyacid synthase (AHAS)-inhibiting herbicides warrant special attention given their residual properties and acute plant toxicity at low concentrations in soil. Soil residual AHAS inhibitors have the potential to influence both leguminous host plants and their bacterial symbiotic partners; consequently, the use of an AHAS inhibitor in a given year can negatively influence the inoculation success and grain yield of legumes cropped in the following year. <p>The present thesis project focused on one of the AHAS inhibiting herbicides (flucarbazone) and studied its potential for carryover injury and negative influence on the success of inoculation in field pea. A series of growth chamber and field experiments were conducted to test the following null hypothesis: the presence of residual flucarbazone in soil does not affect nodulation of field pea by inoculum rhizobia. <p>A growth chamber experiment clearly demonstrated the susceptibility of field pea to the presence of flucarbazone in soil where the lowest concentration of flucarbazone amendment (5 ìg kg1) significantly reduced the crop growth. In contrast, a field study failed to reveal any negative effects of flucarbazone use on crop growth and N2 fixation. <p>It was concluded that if the weather and soil conditions favour decomposition of flucarbazone as described in the present study, flucarbazone applied at the recommended field rate will not persist into the following season at high enough concentrations to negatively influence field pea growth, grain yields, and inoculation success. To ensure safety of rotational crops, it is important to strictly adhere to the herbicide application guidelines. Additionally, producers are cautioned to be particularly aware of the environmental and soil conditions that may reduce the rate of herbicide degradation.

No description available.

A l’échelle mondiale, les prairies fournissent une grande variété de services écosystémiques et sont le support économique de nombreux systèmes d’élevage. Dans un contexte global éminemment changeant, une meilleure compréhension de la structure et du fonctionnement des prairies est incontournable pour proposer à la fois des gestions plus durables des ressources et promouvoir la fourniture de services écosystémiques diversifiés par ces écosystèmes. Les prairies étant des écosystèmes dynamiques et hétérogènes, notre capacité à prédire leur fonctionnement et leurs trajectoires de réponse à un facteur environnemental (climat, gestion) reste un défi scientifique important. Ainsi, dans des prairies pâturées, l’activité de grands herbivores va être facteur d’hétérogénéité des nutriments du sol via l'excrétion. Cependant les effets de ces apports nutritifs en « patchs » et de l'hétérogénéité spatiale du sol sur la structure et les propriétés de la prairie restent peu connus. L’objectif de cette thèse est d’examiner les effets de l'hétérogénéité spatiale de l'azote (N) dans le sol sur l’écosystème prairial, en portant une attention particulière sur les réponses des communautés végétales. Notre démarche a combiné des approches expérimentales et de modélisation pour analyser les impacts d'un certain nombre d'attributs de « patch » (différentes formes d’N, taille et contraste du patch), et leurs interactions possibles avec le régime de pluviométrie ou encore la date des apports en N. Nous montrons que des apports hétérogènes en N augmentent la production des plantes et la variabilité de la biomasse intra-parcelle quel que soit la forme d’N, mais qu’ils ne modifient pas, à court terme, la production à l’échelle de la parcelle prise dans son entier. Néanmoins, des apports hétérogènes d’N-organique favorisent l’asynchronie spatiale et temporelle entre les compartiments plante - sol, avec des implications pour le fonctionnement de la prairie à plus long terme. Contrairement à la production, la structure de la communauté végétale répond significativement à l’hétérogénéité en N, avec une dominance accrue de certaines espèces et un changement dans le rang des espèces subalternes. Contre toute attente, dans cette étude, la quantité de pluie ne modifie pas les effets de l'hétérogénéité sur la production et la structure de la communauté végétale. Des simulations réalisées avec un modèle spatialisé montrent que les effets de l'hétérogénéité sur la production à l’échelle de la parcelle varient selon la taille et le niveau de contraste du patch. Pour un même apport total en N, la production répond positivement à la taille de patch, mais elle diminue dans des conditions de fort contraste en comparaison à des conditions de faible contraste. Nous n’avons pas relevé d’interactions entre la taille de patch, le niveau de contraste de patch ou la date des apports en N sur la production de prairie. D’une manière générale, nos résultats soulignent l'importance de l’hétérogénéité en N pour les processus plante-sol à différentes échelles spatiales et montrent que les effets de l'hétérogénéité varient en fonction des attributs des patchs. Les interactions biotiques (ici la compétition) semblent jouer un rôle relativement plus important que les facteurs abiotiques (ici changements chroniques de pluviométrie) pour les effets d'hétérogénéité. Nous concluons que les impacts de l'hétérogénéité en N sur les processus plante-sol peuvent avoir des conséquences sur les rétroactions plante-sol impliquées dans la régulation des cycles biogéochimiques, et sont à même de fournir des informations utiles pour le développement de pratiques de gestion efficientes dans l’utilisation de l’N. / Grasslands provide a variety of important ecological and economic services worldwide. Improved understanding of grassland structure and function is necessary for the development of sustainable management and maintaining the provision of multiple ecosystem services in a changing environment. However, predicting grassland structure and function is a challenge because grasslands are dynamic, heterogeneous systems. In grazed grasslands, large herbivore activities promote heterogeneity in soil nutrients via excretion, but the effects of patchy nutrient inputs and soil spatial heterogeneity on grassland structure and function remain unclear. This thesis addresses effects of spatial heterogeneity in soil nitrogen (N) for grassland ecosystem structure and function, with particular emphasis on community responses. A combination of experimental and modelling approaches are used to study impacts of a number of different patch attributes (N form, patch size, patch contrast), as well as possible interactions with rainfall regime and timing of N inputs. We find that patchy N inputs enhance within plot-plant production and biomass variability irrespective of N form, but do not modify whole-plot plant production in the short term. Nevertheless, patchy organic N promotes spatial and temporal asynchrony in plant-soil responses, with implications for longer-term grassland function. Unlike plant production, community structure responds significantly to patchy N inputs, with increased community dominance and a shift in the rank of subordinate species. Contrary to expectations, rainfall quantity does not modify heterogeneity effects on either plant production or community structure. Modelling work shows that heterogeneity effects on field-scale production vary depending on patch size and patch contrast. For a fixed total N input, field-scale grassland production responds positively to patch size, but decreases in high- versus low-patch contrast conditions. Patch size does not interact with patch contrast or timing of N inputs on grassland production. Overall, our results highlight the importance of N heterogeneity for plant and soil processes at different spatial scales, and demonstrate that heterogeneity effects vary depending on patch attributes. Biotic interactions (competition) appear to play a relatively greater role than abiotic factors (chronic rainfall changes) for heterogeneity effects. Impacts of N heterogeneity on plant and soil processes may have significant implications on plant-soil feedbacks involved with the regulation of biogeochemical cycling, and provide useful information for the development of efficient N management strategies.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / Previous studies have indicated that blue-green algae may affect runoff, infiltration and erosion at soil surfaces. Using soil plots upon which blue-green algae were grown under an artificial wetting regime, studies were made using simulated rainfall. A 30% clay content Pima soil and a contrasting 8% clay content river-bottom anthony soil were used. Scytonema hoffmanii and Microcoleus vaginatus grew on the pima soil while Schizothrix calcicola developed on the Anthony soil. The results showed that blue-green algal growths significantly reduced the amount of suspended soil material in runoff water as compared with bare soils. Differences in runoff suspended sediments were also related to differences in soil type and simulated rainfall intensity. An analysis of variance of the effects of these 3 factors and their interactions showed that the smaller differences in suspended sediment production on the Anthony soil due to the microvegetation treatment was verified by a highly significant soils-microvegetation interaction, probably because the finer pima soils wash away more easily without stabilizing microvegetation. Also, less vegetation seems to grow on the Anthony soil. Differences in runoff and infiltration volumes and in settleable sediment amounts were not detected.