Made available in DSpace on 2016-04-28T14:58:34Z (GMT). No. of bitstreams: 1 2005- Cristiane Miranda Martins.pdf: 5016347 bytes, checksum: edbb51eb103817d7b3f8ed06497e9daa (MD5) Previous issue date: 2005-02-18 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The present work was carried out at UFRRJ, in Serop?dica, Rio de Janeiro state, to study the influence of tegument and aril on the germination of seeds from two Passifloraceae species: Passiflora edulis f. flavicarpa Deg. and Passiflora alata Curtis. obtained from whole market fruits pur chased at CEASA-RJ. On the first stage the seeds were evaluated in regard to the physiological and sanitary quality at different substrates and temperatures, as well as to the the process of imbibition and hydric restrition. A three-phase pattern of seed imbibition, was observed, germination decreased from the osmotic potential of -0,6 MPa and increased in sand at the temperature alternating from 20 to 30? C in both species. However, sanitary quality was greatest in fungicide treated seeds with removed aril. The results have pointed out that the seeds from both species presented highest percentage of germination upon aril removal, regardless the seed extremity cutting-off. On the second stage seed extracts were obtained with organic solvents of different polarities. These extracts were identified by classes and a sensibility test was performed with Lactuca sativa L. seeds. Steroids and triglicerides were detected in the dichloromethane extract, carbohydrates were detected in methanol extract. Lettuce seeds germination was inhibited by the dichlorinemethanol extract and increased the members of abnormal seedlings and hard seeds. / O presente trabalho foi realizado na UFRRJ, em Serop?dica, RJ, com a finalidade de estudar a influ?ncia do tegumento e do arilo na germina??o de sementes de duas esp?cies de Passifloraceas, Passiflora edulis f. flavicarpa Deg. e Passiflora alata Curtis., obtidas de frutos oriundos de lotes comerciais, adquiridos no CEASA RJ. Na primeira etapa, as sementes foram avaliadas quanto ? qualidade fisiol?gica e sanit?ria, em diferentes substratos e temperaturas, bem como o processo de embebi??o e de restri??o h?drica, nos quais se constatou o modelo trif?sico de embebi??o das sementes, redu??o da germina??o a partir do potencial 0,6 MPa, melhoria da germina??o em substrato areia e na temperatura alternada de 20-30?C, em ambas as esp?cies. Contudo, a qualidade sanit?ria foi maior nas sementes onde foi aplicado fungicida e onde o arilo havia sido removido. Os resultados indicaram que sementes de ambas as esp?cies apresentaram maior porcentagem de germina??o na aus?ncia do arilo, independente do desponte. Na segunda etapa foram obtidos extratos com solventes org?nicos de diferentes polaridades, identificadas ?s classes de subst?ncias presentes e realizado teste de sensibilidade dos mesmos com sementes de Lactuca sativa L. Foram detectados no extrato obtido com diclorometano triglicer?deos e ester?ides; e carboidratos no extrato metan?lico. O extrato diclorometano inibiu a germina??o de sementes de alface, aumentando o n?mero de pl?ntulas anormais e sementes duras, indicando que as subst?ncias contidas nesse extrato influenciaram o processo germinativo.

Made available in DSpace on 2016-04-28T14:58:58Z (GMT). No. of bitstreams: 1 2006- Sandra Regina da Silva Ventura.pdf: 383005 bytes, checksum: 15193624bf97a422073d57287cd049a9 (MD5) Previous issue date: 2006-02-20 / Funda??o Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Solanum melongena L., eggplant, is a culture that has many problems, presenting itself as a hostess of diverse species of bacteria, fungi, mites and insects. The "chinch-bug", Corythaica cyathicollis (COSTA, 1864) is known to cause serious damage to the culture. The research was conducted at the Federal Rural University of Rio de Janeiro (UFRRJ) from August, 2004 to January, 2005, with three nitrogen levels: N0 (without N), N1 (60 kg N/ha), N2 (120 kg N/ha) and three potassium levels: K0 (without K), K1 (30 kg N/ha), K2 (60 kg N/ha). The results showed that the nitrogen levels influenced significantly in the productivity and the quality of the fruit. However, it there was not a significant difference between fruits of 1? and 2? categories, as well as mass and length of the fruit. The greatest occurrence of C. Cyathicollis species was observed when the plants had been fertilized with 120kg of N/ha, and the lesser occurrence in plants fertilized with 60 kg of N/ha. Nighttime presented the lesser occurrence of C. cyathicollis in the culture fertilized with 60 kg of N/ha, and the biggest frequency in plants that had received the fertilization with 120 Kg of N/ha. The lesser damage of C. Cyathicollis was observed in plants that had received the dosage N1 and K1 and the greatest damage was observed in plants with N1 and K0. In the Integrated System of Agroecological Production, located in Serop?dica, RJ, the objective was to evaluate the effect of different doses of organic nitrogen (50, 100, 200 and 300 kg /ha), different soil coverings (grass and Arachis pintoi), conventional system and period of the day (morning, afternoon, evening) in the population of insects associated to the culture of S. melongena in system of organic fertilization. It was not verified in the interaction of the studied factors (doses of nitrogen, soil covering and in the period of the day). However, when cultivated in the conventional system, S. melongena, obtained a greater occurrence of insects (42,26%), and the least occurrence was observed when covering with grass (22,61 %). Relating to the nitrogen, there was a significant difference between the 50 doses kg N/ha and 300 kg N/ha, with 20, 92 and 29, 10 %, respectively. The least occurrence of C. cyathicollis was observed in the evening (27,66 %), significantly differing from morning (39,19 %). The effect of sulfocalcica syrups and of the neem oil I GO ?, in four concentrations, its application methods (contact and ingestion), in the control of the species C. cyathicollis (in the young and adult phases) in condition laboratory, showed a significant difference in the triple interaction analyzes of variance for the number of adult insects living after 72 hours. The use of 2% sulfocalcica syrup, for the contact method, was efficient in the control adults. The neem oil was efficient for nymphs, in low concentration, for the contact method. / Solanum melongena L., berinjela, ? uma cultura que possui muitos problemas, apresentandose como hospedeira de diversas esp?cies de bact?rias, fungos, ?caros e insetos. O inseto conhecido por percevejo manchador , Corythaica cyathicollis (COSTA, 1864) (Hemiptera, Tingidae) destaca-se causando s?rios preju?zos para a cultura. A pesquisa realizada no Campus da UFRRJ, teve o objetivo de quantificar a popula??o de C. cyathicollis (em diferentes per?odos do dia) e seus danos, registrar insetos associados ? plantas de berinjela que receberam aduba??o com diferentes doses de nitrog?nio e pot?ssio, avaliando a produtividade, qualidade e caracter?sticas morfol?gicas dos frutos. Sendo utilizados tr?s n?veis de nitrog?nio: N0 (aus?ncia de N), N1 (60 kg N/ha), N2 (120 kg N/ha) e tr?s n?veis de pot?ssio: K0 (aus?ncia de K), K1 (30 kg N/ha), K2 (60 kg N/ha). Os resultados mostraram que o nitrog?nio influencia significativamente na produtividade e na qualidade dos frutos. Observou-se que maior ocorr?ncia da esp?cie C. Cyathicollis, quando as plantas foram adubadas com 120 kg de N/ha, e a menor ocorr?ncia em plantas adubadas com 60 kg deN/ha. O per?odo da noite apresentou a menor ocorr?ncia da esp?cie C. cyathicollis em plantas de berinjela adubadas com 60 kg de N/ha, e a maior ocorr?ncia em plant as que receberam a aduba??o com 120 kg N/ha. os menores danos de C. Cyathicollis foram observados em plantas que receberam a dosagem N1 e K1 e os maiores danos foi observado em plantas adubadas com N1 e K0. No Sistema Integrado de Produ??o Agroecol?gica, situado em Serop?dica, RJ, o objetivo do trabalho foi avaliar os efeitos de diferentes doses de nitrog?nio org?nico (50, 100, 200 e 300 kg /ha), diferentes coberturas do solo (grama batatais e Arachis pintoi), sistema convencional e per?odo do dia (manh?, tarde, noite) na popula??o de insetos associados ? cultura de S. melongena. Estatisticamente, n?o foi verificada intera??o entre os fatores estudados (doses de nitrog?nio, cobertura do solo e per?odo do dia). Por?m, quando cultivada no sistema convencional, S. melongena, obteve maior ocorr?ncia de insetos (42,26%), e a menor ocorr?ncia foi observada quando na cobertura com grama (22,61 %). Em rela??o ao nitrog?nio, observou-se diferen?a estat?stica significativa entre as doses 50 kg N/ha e 300 kg N/ha, com 20,92 e 29,10 %, respectivamente. A menor ocorr?ncia de C. cyathicollis foi observada no per?odo da noite (27,66 %), diferindo significativamente do per?odo da manh? (39,19 %). O efeito da calda sulfoc?lcica e do ?leo de neem I GO ?, em quatro concentra??es e diferentes modos de aplica??o (contato e ingest?o), foram estudados no controle da esp?cie C. cyathicollis (fase jovem e adulta) em condi??es de laborat?rio. Verificou-se que os produtos foram vi?veis 72 horas de aplica??o. A utiliza??o da calda sulfoc?lcica a 2%, modo de contato foi eficiente para controle de adultos, e o ?leo de neem foi eficiente para ninfas, em baixa concentra??o (0,25%), pelo m?todo de contato.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-06-01T15:58:35Z No. of bitstreams: 1 DANIELE LIMA RODRIGUES.pdf: 451475 bytes, checksum: 4d2837e6e6280d23bbeef937301d23ad (MD5) / Made available in DSpace on 2016-06-01T15:58:36Z (GMT). No. of bitstreams: 1 DANIELE LIMA RODRIGUES.pdf: 451475 bytes, checksum: 4d2837e6e6280d23bbeef937301d23ad (MD5) Previous issue date: 2010-08-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The objective was to find alternative ways to achieve better seed germination under adverse environmental conditions, for lettuce and carrots seeds. The priming is a technique that can reduce the negative effects of environmental stresses on the germination and vigor in this seeds, so the present work we used four treatments: unprimed seeds and three priming methods, among them hydropriming on paper, hydropriming by immersion in distilled water and priming in PEG 6000 -1.5 MPa for lettuce seed and -1.0 MPa for carrot seeds. Initially, the water absorption marches were determined in each conditioning method for seeds of both species and these results were submitted to regression analysis. In lettuce seeds, cv Regina was evaluated jointly or without previous seeds immersion in sodium hypochlorite (NaClO) solution in some tests. The results of priming methods and treatment with NaClO effects in lettuce seeds were subjected to analysis of variance in a factorial arrangement 4 x 2 (4 methods x 2 treatment with NaClO) and means were compared by Tukey test, P <0.05. Tests for evaluating the physiological quality of lettuce seeds were the germination test, speed rate of emission of radicle, speed rate of germination, germination test at 35?C, electrical conductivity and pH test. In the experiment with carrot seed, used two lots of experimental design was completely randomized. The results of priming effects on carrot seeds were subjected to analysis of variance in a factorial 4 x 2 (4 methods x 2 batches) and means were compared by Tukey test, P <0.05. To evaluate the storage effect by up to 60 days after the priming results were subjected to analysis of variance in a factorial 4 x 3 (4 methods x 3 storage periods), and means were compared by Tukey test, P <0.05. Tests for evaluate the physiological quality of carrot seeds were the germination test, first count of germination test, speed rate of emission of radicle, speed rate of germination, germination test at 35?C and germination test with water restriction, and these tests performed immediately after priming and 30 and 60 days after storage. The rate of water absorption was lower in the priming for lettuce seed and obtained superior germination and vigor to other methods. The use of sodium hypochlorite in tests of physiological quality enhanced germination and vigor. The carrot seeds absorption rate was slower in hydropriming on paper and in priming and this methods increased the carrot seeds vigor in lot 2. After 60 days of storage at physiological seed quality decreased, but in hydropriming on paper and priming this effect was smaller. / O objetivo deste trabalho foi encontrar formas alternativas de alcan?ar melhor percentual de germina??o em condi??es ambientais adversas, para sementes de alface e cenoura. O condicionamento fisiol?gico ? uma t?cnica que pode diminuir os efeitos negativos de estresses ambientais sobre a germina??o e o vigor dessas sementes e neste trabalho os tratamentos utilizados foram quatro: sementes n?o condicionadas e tr?s m?todos de condicionamento fisiol?gico, dentre eles hidrocondicionamento em papel, hidrocondicionamento por imers?o em ?gua destilada e osmocondicionamento em solu??o de PEG 6000 -1,5 MPa para sementes de alface e -1,0 MPa para sementes de cenoura. Inicialmente foram determinadas as marchas de absor??o de ?gua em cada m?todo de condicionamento para sementes de ambas as esp?cies e esses resultados foram submetidos ? an?lise de regress?o. Em sementes de alface da cultivar Regina avaliou-se conjuntamente a imers?o pr?via ou n?o das sementes em solu??o de hipoclorito de s?dio (NaClO) em alguns testes. Os resultados dos efeitos dos m?todos de condicionamento e tratamento com NaClO em sementes de alface foram submetidos ? an?lise de vari?ncia em um arranjo fatorial 4 x 2 (4 m?todos x 2 tratamentos com NaClO) e as m?dias foram comparadas pelo teste de Tukey, P<0,05. Na avalia??o da qualidade fisiol?gica foram utilizados o teste de germina??o, primeira contagem do teste de germina??o, ?ndice de velocidade de emiss?o de rad?cula, ?ndice de velocidade de germina??o, teste de germina??o a 35?C, condutividade el?trica e teste de pH. No experimento com sementes de cenoura, utilizaram-se dois lotes da cultivar Bras?lia e o delineamento experimental foi inteiramente casualizado. Os resultados dos efeitos do condicionamento fisiol?gico em sementes de cenoura foram submetidos ? an?lise de vari?ncia em um arranjo fatorial 4 x 2 (4 m?todos x 2 lotes) e as m?dias foram comparadas pelo teste de Tukey, P<0,05. Para a avalia??o do efeito do armazenamento em at? 60 dias ap?s o condicionamento os resultados foram submetidos ? an?lise de vari?ncia em um arranjo fatorial 4 x 3 (4 m?todos x 3 per?odos de armazenamento), e as m?dias foram comparadas pelo teste de Tukey , P<0,05. Os testes para avalia??o da qualidade fisiol?gica das sementes de cenoura foram o teste de germina??o, primeira contagem do teste de germina??o, ?ndice de velocidade de emiss?o de rad?cula, ?ndice de velocidade de germina??o, teste de germina??o a 35?C e teste de germina??o com restri??o h?drica, sendo esses testes executados logo ap?s o condicionamento fisiol?gico, 30 e 60 dias ap?s armazenamento. A taxa de absor??o de ?gua foi menor no osmocondicionamento para sementes de alface e obtendo-se germina??o e vigor superiores aos demais m?todos. O uso de NaClO nos testes de avalia??o da qualidade fisiol?gica em sementes de alface favoreceu a germina??o e o vigor. A taxa de embebi??o de sementes de cenoura foi mais lenta no hidrocondicionamento em papel e no osmocondicionamento e esses m?todos aumentaram o vigor de sementes de cenoura do lote 2. Ap?s 60 dias de armazenamento a qualidade fisiol?gica das sementes diminuiu, por?m no hidrocondicionamento em papel e no osmocondicionamento, esse efeito foi menor.

FAPERJ / The importance of studying soils in order to preserve its functions includes conservation efforts whose goal is to ensure preservation of natural resources for future generations. This study works with the scientific hypothesis that changes in vegetation cover in the watershed of Palmares-Ribeir?o do Saco, Rio de Janeiro State, in the period of 2009-2015, favored the erosion reduction in this area. To verify this trend an estimate of soil losses was made with use of RUSLE (Revised Universal Soil Loss Equation) which allows generating information to build up management plans to secure agricultural production, and to preserve natural resources of the region. Thus, the objective was to develop a methodology for assessment of vegetation affected by seasonality and able to reduce erosion, based on the NDVI (Normalized Difference Vegetation Index) in order to reduce part of values overestimation associated to errors in the RUSLE model. As secondary objective, to compare estimates of erosion and natural erosion potential (NEP) in the period of 2009-2015 with those obtained in the period of 1986-2009, in order to verify environmental impacts in the watershed. The area studied was the watershed of Palmares-Ribeir?o do Saco, located between the municipalities of Paty do Alferes and Miguel Pereira in the state of Rio de Janeiro. Even without the adoption of conservation practices by some of the region farmers, the general aspect of data provided by RUSLE and the NEP in recent years has shown that soil losses are tending to decrease, mainly due to the low recorded rainfall indexes, implying at low erosivity values. / A import?ncia do estudo dos solos a fim de preservar suas fun??es compreende os esfor?os conservacionistas que tem por meta garantir a persist?ncia dos recursos naturais para as gera??es futuras. O presente estudo trabalha com a hip?tese cient?fica de que a evolu??o da cobertura vegetal na bacia hidrogr?fica de Palmares-Ribeir?o do Saco, no estado do Rio de Janeiro, ocorrida no per?odo 2009-2015, favoreceu a redu??o do processo erosivo na bacia. Para averiguar tal tend?ncia foi feita a estimativa da perda de solo com uso da RUSLE (Revised Universal Soil Loss Equation) que possibilita gerar informa??es para montar planos de manejo que visem garantir a produ??o agr?cola preservando os recursos naturais da regi?o. Sendo assim, o objetivo principal foi desenvolver uma metodologia para avalia??o da vegeta??o afetada pela sazonalidade capaz de reduzir processos erosivos, com base no NDVI (Normalized Difference Vegetation Index) a fim de reduzir parte das superestimativas associadas ao erro no modelo da RUSLE. E como objetivo secund?rio comparar as estimativas do processo erosivo e o potencial natural de eros?o (PNE) no per?odo 2009-2015 com aquelas obtidas no per?odo 1986-2009, com intuito de verificar os impactos ambientais ocorridos na bacia hidrogr?fica. A ?rea utilizada como objeto de estudo foi ? bacia hidrogr?fica de Palmares-Ribeir?o do Saco, situada entre os munic?pios de Paty do Alferes e Miguel Pereira no estado do Rio de Janeiro. Mesmo sem haver a ado??o de pr?ticas conservacionistas por partes dos produtores na regi?o, o aspecto geral dos dados fornecidos pela RUSLE e o PNE dos ?ltimos anos revelou que as perdas de solo est?o tendendo ? redu??o, sobretudo por conta dos baixos ?ndices pluviom?tricos registrados, implicando em valores baixos de erosividade.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-03-23T19:09:07Z No. of bitstreams: 1 2017 - Daniele Cabral Michel.pdf: 1915531 bytes, checksum: af036434bb0fd939d8e85a7ff4a1d43f (MD5) / Made available in DSpace on 2018-03-23T19:09:07Z (GMT). No. of bitstreams: 1 2017 - Daniele Cabral Michel.pdf: 1915531 bytes, checksum: af036434bb0fd939d8e85a7ff4a1d43f (MD5) Previous issue date: 2017-02-14 / CAPES / FAPERJ / Centrolobium paraense Tul. popularly known as "pau-rainha", is a naturally occurring legume species from the northern state of Roraima (Brazil) to Panama. It has economic, social and environmental importance for local populations, being a nitrogen fixing species in association with bacteria of the rhizobia group. Thirteen Gram-negative, aerobic, motile with polar flagella, rods shaped bacteria previously isolated from root nodules of C. paraense grown in soils from the Roraima State were submitted to a polyphasic approach characterization. The study involved the carbon source utilization, enzymatic reaction, antibody, pH and NaCl tolerance, 16S rRNA, nodC, nifH and multi locus sequence phylogenetic analysis (MLSA with dnaK, glnII, recA, gyrB and rpoB), G+C content and Average Nucleotide Identity (ANI). Growth of strains was observed at temperature range 20- 36?C (optimal 28?C), pH ranges 5-11 (optimal 6.0-7.0) and 0.1-0.5%NaCl (optimal 0.1- 0.3%). Analysis of 16S rRNA gene placed the strains into two groups within Bradyrhizobium. Closest neighbouring species (98.8%) for group I was B. neotropicale while for group II were twelve species with more than 99% of similarity. MLSA confirmed B. neotropicale BR 10247T as the closest type strain for the group I and B. elkanii USDA 76T and B. pachyrhizi PAC 48T for group II. ANI differentiated group I from the B. neotropicale BR 10247T (79.6%), and group II from B. elkanii USDA 76T and B. pachyrhizi PAC 48T (88.1% and 87.9%, respectively). Fatty acid profiles (majority C16:0 and Summed feature 8 (18:1?6c/18:1?7c) for both groups), DNA G+C content and carbon compound utilization supported the placement of the novel strains in the genus Bradyrhizobium. Gene nodC and nifH of the new strains have in general low similarity with other Bradyrhizobium species. Both groups nodulated plants from the tribes Crotalarieae, Dalbergiae, Genisteae and Phaseoleae. Based on the result obtained, two novel species which the names Bradyrhizobium centrolobii and Bradyrhizobium macuxiense are proposed. / Centrolobium paraense Tul. popularmente conhecido como ?pau-rainha?, ? uma esp?cie de leguminosa que ocorre naturalmente no norte do estado de Roraima (Brasil) ao Panam?. Tem import?ncia econ?mica, social e ambiental para popula??es locais, sendo uma esp?cie fixadora de nitrog?nio (N) em associa??o com bact?rias do grupo dos riz?bios. Treze bact?rias gram-negativas, aer?bicas, com mobilidade atrav?s de flagelos polares e em forma de bastonetes previamente isoladas de n?dulos de ra?zes de Centrolobium paraense cultivadas em solos do estado de Roraima foram submetidas a caracteriza??o com abordagem polif?sica. O estudo envolveu a utiliza??o de fontes de carbono, rea??es enzim?ticas, composi??o de ?cidos graxos das c?lulas, antibi?ticos, pH e toler?ncia a NaCl,16S rRNA, an?lise filogen?tica dos genes nodC, nifH e de sequ?ncias multilocus (MLSA com dnaK, glnII, recA, gyrB e rpoB), conte?do de G+C e identidade m?dia de nucleot?deos (ANI). O crescimento das estirpes foi observado num intervalo de temperatura 20-36?C (?tima 28?C), intervalo de pH de 5-11 (?timo 6,0-7,0) e 0,1-0,5% NaCl (?timo 0,1-0,3%). A an?lise do gene 16S rRNA posicionou as estirpes em dois grupos dentro de Bradyrhizobium. A esp?cie mais pr?xima (98,8%) para o grupo I foi B. neotropicale enquanto para o grupo II foram outras doze esp?cies com mais de 99% de similaridade. MLSA confirmou B. neotropicale BR 10247T como a estirpe tipo mais pr?xima do grupo I e B. elkanii USDA 76T e B. pachyrhizi PAC 48T do grupo II. O ANI diferenciou o grupo I da B. neotropicale BR 10247T (79,6%) e o grupo II da B. elkanii USDA 76T e B. pachyrhizi PAC 48T (88,1 e 87,9 respectivamente. O perfil de ?cidos graxos (predomin?ncia de C16:0 e caracterist?ca somada 8 (18:1?6c/18:1?7c) para ambos os grupos, ANI, o conte?do de G+C e a utiliza??o de compostos de carbono deram suporte ao posicionamento das novas estirpes no g?nero Bradyrhizobium. Os genes nodC e nifH t?m em geral baixa similaridade com outras esp?cies de Bradyrhizobium. Ambos os grupos nodularam plantas de diferentes tribos.

Esta tesis pretende contribuir al conocimiento sobre cómo aplicaciones en superficie de lodos de depuradora de aguas residuales urbanas, utilizados como abonos, pueden afectar a propiedades físicas de los suelos tales como la susceptibilidad a la erosión (pérdida de suelo y escorrentía), la retención de humedad o a la estabilidad de los agregados. En la introducción se hace una breve descripción de los lodos de depuradora: que son, como se generan y que normativa existe acerca de su utilización. A continuación se hace un repaso de los antecedentes de la utilización de lodos de depuradora, especialmente en aplicaciones no agrícolas, y de los trabajos previos del grupo de investigación del CREAF responsable del proyecto global en el que se enmarca este trabajo. Se describen también los objetivos y la organización del trabajo. Se describe después el lugar de experimentación, las características y propiedades generales de los suelos y lodos empleados, así como el diseño experimental usado. La parte principal de la memoria de la tesis está, compuesta por cinco capítulos, en formato de artículos científicos independientes, que versan sobre aspectos concretos de los efectos de los lodos de depuradora sobre algunas propiedades físicas de los suelos: 1. Escorrentía y pérdidas por erosión en suelos enmendados con lodos de depuradora (en ingles). 2. Escorrentía y granulometría de sedimentos en dos suelos tratados con tres tipos de lodos de depuradora (en castellano). 3. Pérdidas de nitrógeno en la escorrentía de un suelo de margas tratado con lodos de depuradora (en castellano). 4. Análisis fractal de la histéresis en las curvas de retención de humedad del suelo influidas por aplicaciones superficiales de lodo (en ingles). 5. Estabilidad de agregados en un suelo franco influida por aplicaciones de lodo (en castellano). Por último, se hace una síntesis de los resultados obtenidos tratando de hacer una interpretación conjunta que permita extraer las conclusiones globales acerca de los diferentes efectos del lodo de depuradora sobre las propiedades físicas de los suelos. Los trabajos de esta tesis se iniciaron en abril de 2001, finalizando la parte experimental en Enero de 2004.

En los últimos años están surgiendo nuevos retos asociados al desarrollo rural, catalizados por una fiebre mundial por la adquisición de tierras a gran escala. Este fenómeno, conocido como ‘acaparamiento de tierras’, está generando controversia en cuanto a si el interés creciente en estas adquisiciones podría beneficiar a las comunidades rurales empobrecidas del campesinado mundial, o al contrario, incidirá en su marginalización. Esta tesis doctoral presenta una recopilación de cuatro artículos que abordan aspectos relevantes para entender mejor los debates, impulsores de cambio, características e impactos de la creciente demanda de tierras y sus implicaciones para el desarrollo rural. Entender los controvertidos debates asociados a los potenciales riesgos y oportunidades del acaparamiento de tierras para las comunidades rurales empobrecidas, nos plantea la siguiente pregunta: ¿qué tipo de pobreza queremos reducir? Como problema que se manifiesta a múltiples escalas y dimensiones, la pobreza es un fenómeno complejo. Será importante tenerlo en cuenta, pues, en estos debates, ya que la adquisición de tierras a gran escala puede aliviar una determinada dimensión de la pobreza, a la vez que estar amenazando otras. Así, el primer artículo aborda los retos epistemológicos y teóricos que surgen al conceptualizar multidimensionalmente la pobreza. En el segundo artículo se investigan los impulsores de cambio del acaparamiento de tierras a nivel global, para poder entender mejor sus implicaciones para el desarrollo rural global y las trayectorias futuras que de él pueden derivarse. Desde una perspectiva biofísica, el artículo argumenta que el acaparamiento de tierras apunta a ser un fenómeno persistente y no efímero: la competición y la lucha por el acceso a la tierra son susceptibles de incrementar en el futuro, provocando nuevos retos para el desarrollo rural a nivel global. El tercer artículo ilustra, para el caso de Camboya, cómo pueden revelarse en la práctica el acaparamiento de tierras y distintas visiones conflictivas sobre el desarrollo rural y la reducción de la pobreza. Basándose en una investigación empírica a nivel nacional, se abordan las características, limitaciones e impactos de las adquisiciones de tierra a gran escala y se ilustra el conflicto fundamental entre los intereses gubernamentales y las realidades locales del desarrollo rural camboyano. Finalmente, el último artículo discute la capacidad del pequeño campesinado para gestionar el decreciente acceso a la tierra a nivel local; una cuestión que seguramente requerirá más atención en el futuro, con la evolución del acaparamiento de tierras. Se presentan así algunas conclusiones sobre el cambio rural global y la emergencia de nuevas ruralidades, caracterizadas por nuevas instituciones y actividades económicas. En resumen, esta tesis combina investigación teórica y empírica con el fin de discutir bajo diversas perspectivas los nuevos retos emergentes del desarrollo rural. Para ello, se destacan las complejas cuestiones, asociadas a la existencia de múltiples escalas y dimensiones de los sistemas rurales, a las que se enfrentan los esfuerzos en torno al desarrollo rural. Asimismo, se presentan también algunas lecciones y conclusiones sobre los debates, impulsores de cambio, impactos y consecuencias futuras del acaparamiento de tierras sobre el desarrollo rural. / Within the recent years, new challenges in rural development have appeared, triggered by the emergence of a global rush for land resources. This phenomenon, well-known under the term ‘land grabbing’, has produced controversial debates surrounding the question whether rising global interest in farmland and related large-scale land deals may benefit poor rural communities across countries of the global South, or whether it may drive the marginalization of the global peasantry. This doctoral dissertation presents a compilation of four research articles that address important issues, relevant to better understand debates, drivers, characteristics and impacts regarding the global land rush and its implications for rural development. In order to understand the controversial debates on potential risks and opportunities of the land rush to poor rural communities, it becomes necessary to deal with the question: what kind of poverty is aimed to be reduced? Poverty is a complex phenomenon, appearing across multiple dimensions and scales. This matters to the debates, as large-scale land deals may help to alleviate poverty in one dimension, while jeopardizing at the same time other poverty dimensions. The first article thus addresses on an epistemological and theoretical level challenges for development efforts that result from a multidimensional conceptualization of poverty. The second article investigates underlying driving forces of the land rush on a global level, in order to better understand future trajectories and implications for global rural development. Taking a biophysical perspective, the article argues that the land rush is likely not an ephemeral phenomenon, but rather might be persistent. Increasing competition and struggles over access to land might increase in the future, thus provoking new challenges for rural development on a global level. The third article illustrates for the case of Cambodia, how both the land rush and conflicting visions of rural development and poverty reduction may unfold in practice. Based on an empirical investigation at the national level, characteristics, constraints and impacts of large-scale land deals are addressed and a fundamental conflict between governmental interests and local realities of rural development is illustrated. Finally, the last article discusses how small-farmers at the village and household level may be able to deal with declining access to land. This is an issue which likely will require more attention in the future, when the land rush further unfolds. Conclusions on global rural change and the emergence of new ruralities, characterized by new economic activities and institutions, are presented. In summary, this dissertation combines general theoretical and empirical case study research in Cambodia, in order to discuss from a variety of different perspectives emerging challenges in rural development. While the dissertation points out the complex issues that rural development studies and efforts may face due to the existence of multiple scales and dimensions of rural systems, also some simple lessons and clear conclusions are presented regarding debates, drivers, impacts and future consequences of the global land rush on rural development.

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Sustainability of irrigated agriculture is a growing concern in the Baix Llobregat area. Although irrigated land accounts for a substantial proportion of food supply to the local market, it has been, and still is increasingly degraded by poor agricultural management. This dissertation focuses on ways to evaluate furrow irrigation and to assess soil water content and soil salinity (temporally and spatially) under usual farmers's management practices. This dissertation meets these goals through an extensive study of relevant literature and the implementation of practical research. The latter was carried out with a case study on representative fields of the area. Empirical and stochastic models were applied to evaluate furrow irrigation as well as to monitor water flow and solute transport in the root zone. This research produced a number of key findings: first, evaluating furrow irrigation confirmed that 40-43 % of the applied water would have been saved in the study fields if irrigation was stopped as soon as soil water deficit was fully recharge taking the amount of water needed for salt leaching into account, and that the application efficiency (AE) would increase from 48% to 84% and from 41% to 68% (Field 1 and Field 2, respectively). Second, the predictions of soil water content using ARIMA models were logical, and the next irrigation time and its effect on soil water content at the depth of interest were correctly estimated. Third, considering the linear relationship eb-sb, by transforming the Hilhorst (2000) model, which is based on the deterministic linear relationship eb-sb, into a time- varying Dynamic Linear Model (DLM) enabled us to validate this relationship under field conditions. An offset esb=0 value was derived that would ensure the accurate prediction of sp from measurements of sb. It was shown that the offset esb=0 varied for each depth in the same soil profile. A reason for this might be changes in soil temperature along the soil profile. The sp was then calculated for each depth in the root zone. Fourth, by using a (multiple input--single output) transfer function model, the results showed that soil water content and soil temperature had a significant impact on soil salinity, and soil salinity, predicted as a function of soil water and soil temperature, was correctly estimated. Finally, applying the analysis of variance (ANOVA), the results showed that the irrigation frequency, according to the farmer's usual management practice, had statistically significant effects on soil salinity behaviour, depending on soil depth and position (furrow, ridge). Moreover, it was shown that at the end of the crop's cycle the farmers left the field with less soil salinity, for each depth, than at the beginning of the crop's agricultural cycle.

La tisoreta comuna Forficula auricularia Linnaeus i Forficula pubescens Gené (Dermaptera : Forficulidae ) poden tenir un paper decisiu com a depredadors. Es va observar compatibilitat entre la tisoreta i nematodes entomopatògens (NEPs) i una activitat dissuassòria en larves de carpocapsa Cydia pomonella L. (Lepidoptera: Tortricidae) mortes per NEPs, reduint l’alimentació de la tisoreta sobre cadàvers que contenien nematodes al seu interior. La presència de tisoretes i aranyes (Araneae) es va observar all llarg de tot l’any, però tan sols les tisoretes van contribuir a reduir les infestacions de pugó llanut. Les re-infestacions procedents de colònies subterrànies no resulten ser rellevants en les regions mediterrànies. D’aquesta manera, el control d'aquest pugó cal que estigui dirigit tant cap a les colònies aèries com a les arrels. L'ús d’infraestructures ecològiques pot augmentar el control biològic de plagues, proporcionant un entorn més favorable i aliments i refugis alternatius als enemics naturals. Anacyclus clavatus Desf., Dorycnium pentaphyllium Scop., Erucastrum nasturtiifolium Poiret, Euphorbia serrata L., Hedysarum confertum Desf., Papaver rhoeas L., Trifolium pratense L. a la primavera, i Atriplex sp., Dittrichia viscosa L., Medicago sativa L., Moricandia arvensis L., Salsola kali L., Sorghum halepense (L.) Pers., Suaeda spicata Willd. i Verbena sp. a la tardor poden proporcionar refugi i aliment a les aranyes. Viburnum tinus L., Euonymous japonicus L. fil. i Pistacia lentiscus L. van mostrar resultats prometedors per a augmentar la riquesa i abundància d'enemics naturals. / La tijereta común Forficula auricularia Linnaeus y Forficula pubescens Gené (Dermaptera : Forficulidae ) pueden tener un papel decisivo como depredadores. Se observó compatibilidad entre la tijereta y nematodos entomopatógenos (NEPs) y una actividad disuasoria en larvas de carpocapsa Cydia pomonella L. (Lepidoptera: Tortricidae) muertas por NEPs, reduciendo la alimentación de la tijereta sobre cadáveres que contenían nematodos en su interior. La presencia de tijeretas y arañas (Araneae) se observó durante todo el año, pero sólo las tijeretas contribuyeron a reducir las infestaciones de pulgón lanígero. Las re-infestaciones procedentes de colonias subterráneas no resultan ser relevantes en las regiones mediterráneas. El control de este pulgón debe dirigirse tanto hacia las colonias aéreas como a las subterráneas. El uso de infraestructuras ecológicas puede aumentar el control biológico de plagas, proporcionando un entorno más favorable y alimentos y refugios alternativos a los enemigos naturales. Anacyclus clavatus Desf., Dorycnium pentaphyllium Scop., Erucastrum nasturtiifolium Poiret, Euphorbia serrata L., Hedysarum confertum Desf., Papaver rhoeas L., Trifolium pratense L. en primavera, y Atriplex sp., Dittrichia viscosa L., Medicago sativa L., Moricandia arvensis L., Salsola kali L., Sorghum halepense ( L. ) Pers., Suaeda spicata Willd. y Verbena sp. en otoño pueden proporcionar refugio y alimento a las arañas. Viburnum tinus L., Euonymous japonicus L. fil. y Pistacia lentiscus L. mostraron resultados prometedores para aumentar la riqueza y abundancia de enemigos naturales. / The European earwig Forficula auricularia Linnaeus and Forficula pubescens Gené (Dermaptera: Forficulidae) may play a crucial role as biocontrol predators. Compatibility between European earwig and entomopathogenic nematodes (EPN) and an earwig deterrent activity in EPN-killed codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) larvae that reduces the foraging of European earwig on insect cadavers containing nematodes was also observed, suggesting compatibility between the European earwig and EPNs was observed. European earwigs and spiders (Araneae) were found throughout the year, but only earwigs contributed to reduce woolly apple aphid infestations. Reinfestations from root colonies are not relevant in Mediterranean areas. The use of ecological infrastructures may increase the biological control of pests, providing a more favorable environment and additional food and shelters for natural enemies. Anacyclus clavatus Desf., Dorycnium pentaphyllium Scop., Erucastrum nasturtiifolium Poiret, Euphorbia serrata L., Hedysarum confertum Desf., Papaver rhoeas L., Trifolium pratense L. in spring, and Atriplex sp., Dittrichia viscosa L., Medicago sativa L., Moricandia arvensis L., Salsola kali L., Sorghum halepense (L.) Pers., Suaeda spicata Willd. and Verbena sp. in fall were observed as native flora useful to provide shelter and food for spiders. Viburnum tinus L., Euonymous japonicus L. fil. and Pistacia lentiscus L. showed promising results in order to enhance abundance and richness of natural enemies.