Estudi dels impactes ambientals del cicle de vida del compost, de la producció a l'apliacació

La gran majoria d'hivernacles situats en clima mediterrani són de cost relativament baix i de tecnologia senzilla. El cultiu en hivernacle te com a objectiu principal incrementar la producció agrícola per unitat de superfície mitjançant l'aïllament de les condicions del medi. Aquest projecte presenta inventaris detallats i de qualitat del cicle de vida complet del compost amb aplicació en aire lliure i en hivernacle, aportant informació dels impactes ambientals i avaluant la viabilitat agronómica del compost com a fertilitzant quan s’aplica en cultius hortícoles. S’han considerat quatre opcions de cultiu, depenent del tipus de fertilitzant utilitzat (fertilitzans minerals o compost) i de si el cultiu és a l’aire lliure o en hivernacle. Les dades s’han obtingut experimentalment en parceles pilot i en una planta de compostatge industrial, ambdos localitzats prop de Barcelona, en una àrea mediterrànea. Per al cultiu en hivernacle, s’han obtingut produccions de tomàquet superiors a les d’aire lliure en el cas d’aplicar fertilitzants minerals, mentre l’ús de compani són de cost relativament baix i de tecnologia senzilla.

Anàlisi paramètrica de l'assaig a compressió d'un panell de material compost rigiditzat amb tres nervis

L’objectiu d’aquest treball és desenvolupar una metodologia per realitzar l’anàlisiparamètrica de l’assaig de compressió d’un panell de material compost rigiditzat ambtres nervis. En primer lloc és necessari desenvolupar un sistema automatitzat per generar i avaluar el conjunt de parametritzacions. A continuació, s’estudiaran quines variables d’estat són les més adequades per representar el vinclament local, la flexió global, la càrrega crítica de desestabilització i l’índex de fallada en l’anàlisi paramètrica. La modelització amb el mètode dels elements finits serveix per simular l’assaig a compressió del panell. La simulació es realitza mitjançant un càlcul no lineal, per estudiar la desestabilització i els fenòmens no lineals que pateix el panell. L’estudi es complementa amb una anàlisi modal i una anàlisi lineal

Estudis dirigits a la síntesi d'un nou compost fotocròmic amb aplicacions en recobriments protectors fotosensibles

Els compostos fotocròmics es caracteritzen per la seva capacitat d’interconvertir-se entre dos estats amb colors diferents en ser sotmesos a irradiació amb llum, motiu pel qual prenen un gran interès en la comunitat científica per les potencials aplicacions que això els confereix. Una d’aquestes aplicacions és la preparació de recobriments protectors fotosensibles que permetin regular òpticament el pas de llum a través d’ells o la reflexió de llum a la seva superfície. Aquest tipus de sistemes poden ser utilitzats com a filtres en dispositius optoelectrònics o recobriments de miralls i lents oftalmològiques. Aquest treball recull els estudis dirigits a la síntesi d’un nou potencial compost fotocròmic per a ser utilitzat en recobriments protectors fotosensibles. Per tal d’obtenir el compost objectiu, s’ha abordat una primera ruta sintètica que ha hagut d’ésser abandonada degut a la molt baixa solubilitat d’un dels intermedis i la dificultat per fer-lo reaccionar que aquest fet comporta. Seguidament s’ha ideat una segona ruta sintètica i s’ha realitzat un extens estudi sobre les condicions de reacció de l’últim pas sintètic. Malauradament, però, no s’ha aconseguit obtenir el compost objectiu.

Effect of refuge supplement on Audouin's gull chick survival

One of the main threats to Audouin´s gull (Larus audouinii) at Chafarinas Islands is predation on eggs and chicks by the yellow-legged gull (Larus cachinnans). During the 1999 and 2000 breeding seasons we tested the effects of supplementary refuge availability on chick survival. Well before the laying period, nine adjacent enclosures were erected inside Audouin´s gull´s breeding grounds and some of them were supplied with artificial refuges. Our results showed significantly greater chick survival in the enclosures with artificial refuges than in control ones. In 2000, an overall lower breeding success of Audouin´s gull and a dilution of the refuge effect were observed. These results were probably related to food-shortage that year. We suggest that, along with other factors, an increase in refuge availability may significantly enhance Audouin´s gull chick survival.

Figures: exercicis a una i dues veus rítmiques, en compàs simple i compost

Exercicis pràctics de ritme.

Effect of refuge supplement on Audouin's gull chick survival

One of the main threats to Audouin´s gull (Larus audouinii) at Chafarinas Islands is predation on eggs and chicks by the yellow-legged gull (Larus cachinnans). During the 1999 and 2000 breeding seasons we tested the effects of supplementary refuge availability on chick survival. Well before the laying period, nine adjacent enclosures were erected inside Audouin´s gull´s breeding grounds and some of them were supplied with artificial refuges. Our results showed significantly greater chick survival in the enclosures with artificial refuges than in control ones. In 2000, an overall lower breeding success of Audouin´s gull and a dilution of the refuge effect were observed. These results were probably related to food-shortage that year. We suggest that, along with other factors, an increase in refuge availability may significantly enhance Audouin´s gull chick survival.

Enhanced Botrytis cinerea resistance of Arabidopsis plants grown in compost may be explained by increased expression of defense-related genes, as revealed by microarray analysis

Composts are the products obtained after the aerobic degradation of different types of organic matter waste and can be used as substrates or substrate/soil amendments for plant cultivation. There is a small but increasing number of reports that suggest that foliar diseases may be reduced when using compost, rather than standard substrates, as growing medium. The purpose of this study was to examine the gene expression alteration produced by the compost to gain knowledge of the mechanisms involved in compost-induced systemic resistance. A compost from olive marc and olive tree leaves was able to induce resistance against Botrytis cinerea in Arabidopsis, unlike the standard substrate, perlite. Microarray analyses revealed that 178 genes were differently expressed, with a fold change cut-off of 1, of which 155 were up-regulated and 23 were down-regulated in compost-grown, as against perlite-grown plants. A functional enrichment study of up-regulated genes revealed that 38 Gene Ontology terms were significantly enriched. Response to stress, biotic stimulus, other organism, bacterium, fungus, chemical and abiotic stimulus, SA and ABA stimulus, oxidative stress, water, temperature and cold were significantly enriched, as were immune and defense responses, systemic acquired resistance, secondary metabolic process and oxireductase activity. Interestingly, PR1 expression, which was equally enhanced by growing the plants in compost and by B. cinerea inoculation, was further boosted in compost-grown pathogen-inoculated plants. Compost triggered a plant response that shares similarities with both systemic acquired resistance and ABA-dependent/independent abiotic stress responses.

Phosphorous and nitrogen changes in compost-amended schist soils in vineyards in the D.O. Priorat wine-producing area (NE Spain)

The impact, on nitrogen and phosphorous dynamics, of applying compost at different rates was investigated in soils developed on schist in new terraced vineyards (NTV) and in undisturbed areas (NC). Repacked soil columns amended with 0 (control), 50 t ha –1 (T1) and 100 t ha–1 (T2) of compost were studied under laboratory conditions simulating both situations. The columns were maintained for 1 year, during which time a total of 300 mm of simulated rainfall was applied in ten 30 mm applications. Soil organic matter (OM), nitrogen and phosphorous contents were analysed at the end of the study period and leachates were analysed after each simulated rainfall event. Significant differences in nitrate leaching were observed between the control and the treated soils and these differences were greater in the NC (control = 1.368 g, T1 = 1.526 g and T2 = 1.686 g) than in the NTV soils (control = 0.61 g, T1 = = 1.068 g and T2 = 1.283 g). The relative effect was greater in the NTV soils (T1/control = 1.11 vs. 1.75 and T2/control = 1.23 vs. 2.1 for NC and NTV, respectively). The nitrate concentration in the leached water reached up to 400 mg L–1, which implied a risk of groundwater pollution. Phosphorous losses through leaching were very low with concentrations of < 0.15 mg L–1, without any significant differences between treatments. The phosphorous concentrations in the surface horizon increased by 50.8% in T1 and by 66.8% in T2 in the NC soils, compared with increases of 20.3% and 38%, respectively, in the NTV soils. Due to the high infiltration capacity of the study soils, leaching effects must be considered in order to prevent groundwater pollution.