• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 64
  • 17
  • 14
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 2
  • Tagged with
  • 116
  • 59
  • 24
  • 19
  • 16
  • 16
  • 11
  • 11
  • 10
  • 10
  • 10
  • 9
  • 9
  • 9
  • 8
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Acompanhamento da variacao mineral de duas cultivares de guandu (Cajanus cajan(L.)Millsp) submetidas a diferentes doses de fertilizantes, pelo metodo de analise por ativacao com neutrons

PIASENTIN, RICARDO M. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:45:20Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:17Z (GMT). No. of bitstreams: 1 07177.pdf: 26753292 bytes, checksum: 81a931adb15e4e0a05ed87c5b6230b93 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
92

Caracterização de iodo de esgotos de lagoa anaeróbia acondicionado em bags visando a sua disposição : estudo de caso - ETE Pedregulho/SP / Characterization of sewage sludge anaerobic pond paked in bags aimed at its disposal : case study - ETE Pedregulho/SP

Pim, Vanderlei 21 August 2018 (has links)
Orientadores: Edevar Luvizotto Junior, Bruno Coraucci Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-21T12:01:23Z (GMT). No. of bitstreams: 1 Pim_Vanderlei_M.pdf: 7573689 bytes, checksum: d7840f9ac209c660c1efa3ccb0efc04f (MD5) Previous issue date: 2012 / Resumo: As preocupações com o adequado destino dos lodos de esgotos fizeram da reciclagem uma alternativa de grande perspectiva de evolução no Brasil. O presente estudo visa avaliar o lodo da lagoa anaeróbia da ETE Pedregulho/SP, operada pela Sabesp, bombeado e acondicionado em bags, em relação a sua qualidade, visando disposição. Foram utilizados 3 bags diferentes e realizadas análises antes, durante e depois do bombeamento, percebendo que, durante o tempo, as permeabilidades dos bags não são constantes e que, houve alterações nas caraterísticas do lodo quando nos bags. Foram removidos 614 m3 de lodo da lagoa anaeróbia, havendo melhora na eficiência da ETE. A retração volumétrica do lodo nos bags permitiu constatar a interferência das chuvas no volume dos bags. Houve também uma avaliação do líquido que percolava dos bags. O lodo foi caracterizado como resíduo Classe II A (não perigoso, não Inerte) pela ABNT NBR 10.004:2002 e considerado possível de ser disposto em aterro sanitário; a técnica da respirometria associado à caracterização pela Resolução CONAMA 375/06 - MMA torna o lodo da lagoa anaeróbia passível de aplicação agrícola e, o atendimento às exigências do Ministério da Agricultura permite buscar o registro, especificação e classificação do lodo como fertilizante, biofertilizante ou condicionador de solo. A remoção teve um custo de R$159,92/m3. Considerando as condições avaliadas nesta pesquisa, conclui-se que a utilização agrícola é a forma mais viável de disposição final de lodo de esgotos / Abstract: Concerns about the appropriate destination of sewage sludge made recycling a great perspective of alternative development in Brazil. The present study aims to evaluate the sludge from the anaerobic pond ETE Pedregulho / SP, operated by Sabesp, pumped and stored in bags, in relation to its quality, aiming to disposal. Three different bags were used and analyzed before, during and after pumping, it was noticed that during the time the permeability of the bags are not constant and there were changes in the characteristics of the sludge when in the bags. 614 m3 of sludge from the anaerobic pond were removed, with an improvement in the efficiency of ETE. The evoluation of volumetric shrinkage of the sludge in bags revealed the interference of rain in the volume of bags. There was an evaluation of liquid that percolated. The waste sludge was characterized as Class II A (non-hazardous, non-Inert) by the ABNT NBR 10.004:2002 and considered possible to be disposed in landfill; the technique of respirometry associated to the characterization by Resolução CONAMA 375/06 - MMA makes the sludge of the anaerobic pond be applied for agricultural purposes compliance with the requirements of the Ministry of Agriculture allows searching the record, specification and classification of the sludge as fertilizer, biofertilizer and soil conditioner. The removal had a cost of R$159,92 / m3. Considering the conditions evaluated in this study, it was concluded that agricultural use is the most viable form of disposal of sewage sludge / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil
93

Cattle manure, scalping and soil wetness effects on some physical properties of a hardsetting soil and associated early maize growth

Nciizah, Adornis Dakarai January 2011 (has links)
Most soils in the Eastern Cape Province, South Africa are shallow and are low in organic matter. Therefore these soils are structurally fragile and highly susceptible to inherent degradative processes like hardsetting. The objective of this study was to determine the effect of cattle manure, scalping and soil wetness on aggregate stability, penetration resistance and early maize growth in hardsetting soils. Glasshouse and field studies were conducted to determine the effect of cattle manure on aggregate stability and penetration resistance of freshly exposed topsoils by scalping at 0, 10 and 20 cm depths. In the glasshouse cattle manure was applied at 0 and 20 Mg/ha and matric suction was kept at ~ 30 and ~ 400 kPa; contrasting high and low soil wetness. Three soils were put in pots and arranged in a randomized complete block 3 2 2 factorial design. The field study was done at the University of Fort Hare research farm and the treatments were arranged in a split-plot complete randomized design with three replications. Scalping treatment was the main plot whilst the quantity of the cattle manure applied was the sub plot. Cattle manure increased mean weight diameter (MWD) by between 48% and 71% under glasshouse and between 18% and 33% under field conditions, depending on the soil wetting rate. Cattle manure reduced MWD when the soil under field condition was subjected to mechanical shaking. Soil penetration resistance decreased linearly, with increasing soil wetness but it rapidly increased with increase in matric suction up to ~200 kPa and thereafter the rate of increase reduced. In the glasshouse, all treatments had no significant effects on shoot dry weight but low matric suction increased root dry weight by 133%. Interaction of cattle manure and low matric suction reduced shoot length by 6%, shoot fresh weight by 25%, root surface area by 36%, root length by 5% and root fresh weight by 29% compared to the control. In contrast, application of cattle manure and high matric suction increased shoot length by 37%, shoot fresh weight by 136%, root surface area by 159%, root length by 94% and root fresh weight by 119%. In the field, cattle manure application increased root length density and shoot dry matter by 26% and 30% respectively. Cattle manure improved the stability of aggregates of the hardsetting soil under rapid or slow water intake conditions experienced during rainfall or irrigation. However, under field conditions cattle manure acted as a deflocculant and decreased the stability of aggregates when mechanical stress was applied. The effectiveness of cattle manure in improving maize growth in hardsetting soils was determined by matric suction.
94

Improving sanitization and fertiliser value of dairy manure and waste paper mixtures enriched with rock phosphate through combined thermophilic composting and vermicomposting

Mupondi, Lushian Tapiwa January 2010 (has links)
Thermophilic composting (TC) and vermicomposting (V) are the two most common methods used for biological stabilization of solid organic wastes. Both have their advantages and disadvantages but the proposed method of combining composting and vermicomposting (CV) borrows pertinent attributes from each of the two methods and combines them to enhance overall process and product qualities. Dairy manure and waste paper are two wastes produced in large quantities at the University of Fort Hare. The study was carried out to address the following specific objectives, to determine (i) the effectiveness of combined thermophilic composting and vermicomposting on the biodegradation and sanitization of mixtures of dairy manure and paper waste, (ii) an optimum precomposting period for dairy manure paper waste mixtures that results in vermicomposts of good nutritional quality and whose use will not jeopardize human health, (iii) the effectiveness of phosphate rock (PR) in increasing available P and degradation and nutrient content of dairy manure-paper vermicomposts, (iv) the physicochemical properties of vermicompost substituted pine bark compost and performance of resultant growing medium on plant growth and nutrient uptake. Results of this study revealed that wastes with a C: N ratio of 30 were more suitable for both V and CV as their composts were more stabilized and with higher nutrient contents than composts made from wastes with a C: N ratio of 45. Both V and CV were effective methods for the biodegradation of dairy manure and paper waste mixtures with C: N ratio of 30 but the latter was more effective in the biodegradation of waste mixtures with a C: N ratio of 45. The combinination of composting and vermicomposting eliminated the indicator pathogen E. coli 0157 from the final composts whereas V only managed to reduce the pathogen population. iv A follow up study was done to determine the effects of precomposting on pathogen numbers so as to come up with a suitable precomposting period to use when combine composting dairy manure-waste paper mixtures. Results of this study showed that over 95% of fecal coliforms, E. coli and of E. coli 0157 were eliminated from the wastes within one week of precomposting and total elimination of these and protozoan (oo)cysts achieved after 3 weeks of precomposting. The vermicomposts pathogen content was related to the waste’s precomposting period. Final vermicomposts pathogen content was reduced and varied according to precomposting period. Vermicomposts from wastes precomposted for over two weeks were less stabilized, less humified and had less nutrient contents compared to vermicomposts from wastes that were precomposted for one week or less. The findings suggest that a precomposting period of one week is ideal for the effective vermicomposting of dairy manure-waste paper mixtures. Results of the P enrichment study indicated an increase in the inorganic phosphate and a reduction in the organic phosphate fractions of dairy manure-waste paper vermicompost that were enriched with PR. This implied an increase in mineralization of organic matter and or solubilization of PR with vermicomposting time. Applying PR to dairy manure-waste paper mixtures also enhanced degradation and had increased N and P contents of dairy manure-waste paper vermicomposts. Earthworms accumulated heavy metals in their bodies and reduced heavy metal contents of vermicomposts. A study to determine the physicochemical properties of vermicompost substituted pine bark compost and performance of resultant growing medium on plant growth and nutrient uptake was done. Results obtained revealed that increasing proportions of dairy manure vermicomposts in pine bark compost improved tomato plant height, stem girth, shoot and root dry weights. v Tomatoes grew best in the 40 to 60% CV substituted pine bark and application of Horticote (7:2:1 (22)) fertilizer significantly increased plant growth in all media. Progressive substitution pine bark with dairy manure vermicomposts resulted in a decrease in the percentage total porosity, percentage air space whilst bulk density, water holding capacity, particle density, pH, electrical conductivity and N and P levels increased. Precomposting wastes not only reduced and or eliminated pathogens but also improved the stabilisation and nutrient content of dairy manure waste paper mixtures. The application of PR to dairy manure waste paper mixtures improved the chemical and physical properties of vermicomposts. Earthworms bio-accumulated the heavy metals Cd, Cr, Cu, Pb and Zn whilst the contents of these in the vermicomposts declined. It is, therefore, recommended that dairy manure waste paper mixtures be precomposted for one week for sanitization followed by PR application and vermicomposting for stabilization and improved nutrients contents of resultant vermicomposts. Substitution of pine bark compost with 40 to 60 % PR-enriched vermicompost produced a growing medium with superior physical and chemical properties which supported good seedling growth. However, for optimum seedling growth, supplementation with mineral fertilizer was found to be necessary.
95

Animal manures and urea as nitrogen sources for corn production in Québec

Xie, Rongjing. January 1985 (has links)
No description available.
96

Nitrogen turnover and leaching in cropping systems with ryegrass catch crops /

Aronsson, Helena, January 1900 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
97

Organic inputs from agroforestry trees on farms for improving soil quality and crop productivity in Ethiopia /

Teklay, Tesfay, January 2005 (has links) (PDF)
Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 5 uppsatser.
98

Efeitos abióticos na composição do óleo essencial de Lippia gracilis: influência na mortalidade e repelência de Sitophilus zeamais / Abiotic effects on the composition of the essential oil of Lippia gracilis: influence on mortality and repellency of the Sitophilus zeamais

Souza, Felipe Hermínio Oliveira 28 February 2013 (has links)
Abiotic factors may interfere in production of plant secondary metabolites and consequently influence the bioactivity of these compounds on insect pests. Thus, this study aimed to evaluate the influence of different agricultural practices (irrigation, mineral fertilizer and organic manure) in chemical composition of the essential oil (EO) of Lippia gracilis and its effects on the maize weevil Sitophilus zeamais.The chemical compositions of EO from plants of L. gracilis cultured on different treatments were analyzed using GC-MS and GC-FID. The carvacrol was the major component of EO in different agricultural practices followed by thymol and ñ-cymene.These three monoterpenes were used in subsequent bioassays. Cultivation practices did not significantly affect the composition of the OEs of L. gracilis. However, small variations in the composition of EOs resulted in different biological responses to S. zeamais. All EOs of L. gracilis and its main monoterpenes applied topically showed low toxicity on S. zeamais after 84 hours exposure at a dose 10 mg g-1. However, these same compounds were highly toxic to S. zeamais by fumigation. The time required to cause 50% mortality of the pest was 28.4 hours on average, ranging from 17.3 to 40.8 hours between treatments. The toxic action of carvacrol, thymol and EOs of L. gracilis (no irrigation/fertilization mineral and 40 t ha-1 organic fertilizer) were the fastest, LT50=18,3. The magnitude of the variation of CL50 and CL99 were 1.9 and 2.1 times. The concentration needed to cause 50 to 99% mortality of the pest was on average 69 and 260 ìl l-1, respectively.Considering the LC50 and LC99, the more toxic OEs of L. gracilis were obtained from plants grown in the absence of mineral fertilizer and in the presence of organic manure with of 20, 40 and 60 t ha-1 (no irrigation) and 40 and 60 t ha-1 (with irrigation). Much of the activity of the EOs of L. gracilis is due to the major compound carvacrol. It took only 27.2 and 92.2 l ìl l-1 to cause 50% and 99 % mortality of adult S. zeamais. The toxic activity of this monoterpene was still one of the fastest (LT50 = 17.3 and LT99 = 70.8 hours). Already the thymol and ñ-cymene awere compounds of low toxicity to adult S. zeamais (LC50= 4,4 e 26,1 respectively). Generally, the EOs of L. gracilis and the monoterpenes applied at lower concentrations (0.01 and 0.1% v/v) showed a neutral effect (not significant) or attractive (negative and significant) in all periods analyzed. At concentration 10% (v/v) almost all treatments were repellents to S. zeamais at any time analyzed (repellence > 50%). Major indexes repellency (54-86%) were observed in treatments irrigated and with maximum organic manure, at concentrations of 1 and 10% (v/v). Thus, our results show the great potential of EO of L. gracilis and its major compound for the development of new products and programs for use in integrated pest management of stored grain. / Fatores abioticos podem interferir na producao de metabolitos secundarios de plantas e consequentemente influenciar na bioatividade destes compostos sobre insetos-praga. Assim, neste trabalho objetivou-se avaliar a influencia de diferentes praticas agricolas (irrigacao, adubacao quimica e organica) na composicao quimica do oleo essencial (OE) de Lippia gracilis e seus efeitos na mortalidade e repelencia do gorgulho do milho Sitophilus zeamais. As composicoes quimicas dos OEs das plantas de L. gracilis cultivadas sobre diferentes tratamentos foram analisadas usando CG-MS e CG-FID. As praticas de cultivo nao afetaram significativamente a composicao dos OEs de L. gracilis, o carvacrol foi o componente majoritario dos OEs nas diferentes praticas agricolas, seguido pelo timol e Ï-cimeno. Estes tres monoterpenos foram utilizados nos bioensaios posteriores. Pequenas variacoes na composicao dos OEs resultaram em diferentes respostas biologicas de S. zeamais. Todos os OEs de L. gracilis aplicados topicamente mostraram baixa toxicidade sobre S. zeamais apos 84 horas de exposicao na dose 10 mg g-1. Contudo, estes mesmos compostos foram altamente toxicos a S. zeamais por fumigacao. O tempo necessario para causar 50% de mortalidade desta praga foi em media 28,4 horas; variando de 17,3 a 40,8 horas entre os tratamentos. A acao toxica do carvacrol, timol e do OEs de L. gracilis (ausencia de irrigacao/adubacao mineral e 40 t ha-1 de adubacao organica) foram as mais rapidas, TL50=18,3. A magnitude da variacao das CL50 e CL99 foram de 1,9 e 2,1 vezes. A concentracao necessaria para causar 50 e 99% de mortalidade desta praga foi em media 69 e 260 Êl l-1, respectivamente. Considerando as CL50 e CL99, os OEs de L. gracilis mais toxicos foram obtidos de plantas cultivadas na ausencia de adubacao mineral e presenca de adubacao organica com 20, 40 e 60 t ha-1 (sem irrigacao) e 40 e 60 t ha-1 (com irrigacao). Grande parte da atividade dos OEs de L. gracilis deve-se ao composto majoritario carvacrol. Foram necessarios apenas 27,2 e 92,2 Êl l-1 para causar 50 e 99% de mortalidade a adultos de S. zeamais. A atividade toxica deste monoterpeno foi de TL50 = 17,3 e TL99 = 70,8 horas. Ja o timol e Ï-cimeno foram os compostos de menor toxicidade a adultos de S. zeamais (CL50= 4,4 e 26,1 respectivamente). De forma geral, os OEs de L. gracilis e os monoterpenos utilizados nas menores concentracoes (0,01 e 0,1% v/v) apresentaram efeito neutro (nao significativo) ou atrativo (negativo e significativo) em todos os tempos analisados. Ja na concentracao 10% (v/v) quase todos os tratamentos foram repelentes a S. zeamais em qualquer tempo analisado (repelencia > 50%). Maiores indices de repelencia (54-86%) foram observadas nos tratamentos irrigados com maxima adubacao organica e concentracao 1 e 10% (v/v). Assim, nossos resultados mostram o grande potencial do OE de L. gracilis e seu composto majoritario para o desenvolvimento de novos produtos e utilizacao em programas de manejo integrado de pragas de graos armazenados.
99

Potencial da Gliciridia em consorciação com Capim marandu em substituição a adubação nitrogenada

Araujo, Helber Rodrigues de 27 June 2014 (has links)
The experiment was conducted to evaluate the availability of forage and weight gain in grazing Marandu Grass (Brachiaria brizantha (Hochst. ex. A. Rich.) Webster cv. Marandu) fertilized with nitrogen in the absence and presence of Gliricidia (Gliricidia sepium (Jacq ) Kunth , Walp), conducted in the Experimental Jorge Prado Sobral , belonging to Embrapa Tabuleiros Costeiros, in Nossa Senhora das Dores - SE, during the rainy season (May to October) and of water restrictions, dry period (November to April) in the years 2008 to 2011. The treatments had consisted of four doses of nitrogen (0, 80, 160 and 240 kg/ha.year) applied in grass pastures Marandu and consortium use Gliricidia with Marandu Grass (0 kg/ha.year of N), wrapped in an experimental design of randomized blocks with six repetitions. The Marandu pastures were grazed in intermittent stocking system, in Rotary, grazing with seven days of occupation and 35 days of rest in the rainy season and seven days of occupation and 49 days of rest in the dry period. During the rainy season and drought treatments composted with nitrogen provide increased availability of total dry matter, leaf, culm in effect positive in stocking rate, individual weight gain and weight gain per area of cattle. It was noted also that in the rainy season there was an increase in the percentage of leaf and culm, reducing the percentage of dead material and increasing crude protein of leaf and culm. While in the dry season it was noted an increase in the availability of biomass of dead material effect this hydric deficit arising from the period. In the rainy season between the Consortium marandu grass and Gliricidia showed similar or higher efficiency the largest doses of nitrogen to increase the percentage of leaf, crude protein and weight gain per area of cattle. While in the dry season the consortium between grass Marandu and Gliricidia showed similar or higher efficiency the largest doses of nitrogen to increase the availability of individual sheet, weight gain, and stocking rate weight gain per area of cattle. / O experimento foi desenvolvido objetivando avaliar a disponibilidade de forragem e o ganho de peso em pastagem de Capim Marandu (Brachiaria brizantha (Hochst. ex. A. Rich.) Webster cv. Marandu) adubada com nitrogênio ou consorciado com Gliricidia (Gliricidia sepium (Jacq.), Kunth, Walp). Este experimento foi conduzido no Campo Experimental Jorge do Prado Sobral, pertencente a Embrapa Tabuleiros Costeiros, em Nossa Senhora das Dores - SE, durante o período chuvoso (maio a outubro) e de restrições hídricas, período da seca, (novembro a abril) nos anos de 2008 a 2011. Os tratamentos constituíram-se de quatro doses de nitrogênio (0, 80, 160 e 240 kg/ha/ano) aplicados em pastos de capim Marandu e do uso do consórcio Gliricidia com Capim Marandu (0 kg/ha/ano de N), disposto em um delineamento experimental de blocos casualizados com seis repetições. Os pastos de Marandu foram manejados em sistema de lotação intermitente, em pastejo rotativo, com sete dias de ocupação e 35 dias de descanso no período das chuvas e sete dias de ocupação e 49 dias de descanso no período da seca. Durante o período das chuvas e da seca os tratamentos adubados com nitrogênio proporcionam aumento na disponibilidade de matéria seca total, folha, colmo com efeito positivo na taxa de lotação, ganho de peso individual e ganho de peso por área dos bovinos. Constatou-se, também, que no período das chuvas ocorreu um aumento dos percentuais de folha e colmo, redução do percentual de material morto e aumento da proteína bruta de folha e colmo. Enquanto que no período seco notou-se um incremento na disponibilidade de biomassa de material morto efeito este decorrente do déficit hídrico do período. No período das chuvas consórcio entre o capim-marandu e a Gliricidia mostrou eficiência semelhante ou superior as maiores doses de nitrogênio para incrementar do percentual de folha, proteína bruta e ganho de peso por área dos bovinos. Enquanto que no período seco o consórcio entre o capim Marandu e a Gliricidia mostrou eficiência semelhante ou superior as maiores doses de nitrogênio para incrementar a disponibilidade de folha, ganho de peso individual, taxa de lotação e ganho de peso por área dos bovinos.
100

Manure production and nutrient management in pasture-based dairy production systems

Svinurai, Walter January 2010 (has links)
Manure production and nutrient management in pasture-based dairy production systems by Walter Svinurai The effect of dietary treatments on nutrient excretion was determined and an attempt to improving the retention of excreted nitrogen in stored manure using Aloe ferox leaf gel (AFLG) and pine bark was conducted at a pasture-based dairy farm. The animal mass-balance method was used to determine nutrient excretion by cows fed on three dietary treatments, Lolium perrene-based treatment (LP), Lolium multiforium-based treatment (LM) and Lolium perenne- Trifolium repens -based treatment (LTF). In separate experiments, slurry from dairy cows fed LM was amended with AFLG and pine bark at concentrations of 25, 50, 75 and 100 g/l and stored under anaerobic conditions for 16 days. The highest and lowest excretions of N, P and K were observed in LM and LP treatments, respectively. Increasing dietary N improved K and N retention in milk and, consequently increased milk urea nitrogen (MUN) and N excretion (P < 0.05). The concentrations of AFLG affected N and P retention in manure (P < 0.05). The highest retention in total Kjeldahl nitrogen (TKN) of the initial was 42% AFLG at 25g/l inclusion rate. Ammonium nitrogen (AMN) concentration increased significantly due to the interactive effect of AFLG inclusion rate and time. Pine bark powder significantly improved N and P retention in manure at all concentrations. The retention in TKN was higher (P < 0.05) at 25g/l pine bark powder than other concentrations. The interaction effect of inclusion rate and time increased iii AMN (P < 0.05). Dietary treatments significantly affected nutrient excretion, and AFLG and pine bark considerably improved N retention in stored slurry. Findings from the filed trial suggest the need for more attention on managing dietary nutrients in the post-rainy and cool-dry season when growth of pasture influenced choice of dietary treatments that led to high nutrient excretion. Field simulation of the additives to determine their efficacy and environmental hazards was recommended.

Page generated in 0.0578 seconds