Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 92-104).

Thesis (M.Sc.(Agric.))(Agronomy)--University of Pretoria, 2007. / Includes summary. Includes bibliographic references. Available on the Internet via the World Wide Web.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (MScAgric)--Stellenbosch University, 1969. / ENGLISH ABSTRACT: no abstract available / AFRIKAANSE OPSOMMING: geen opsomming

Thesis (MScAgric)--Stellenbosch University, 1965. / ENGLISH ABSTRACT: no abstract available / AFRIKAANSE OPSOMMING: geen opsomming

Low soil fertility has been identified to be among the major causes of low pasture quantity and quality. Scarcity of high quality forage mainly during the dry season threatens animal productivity in some areas of South Africa, thus the need for identifying livestock feed alternatives. Pigeon pea is a woody legume that has continually been an important shrub in agroforestry and can provide protein-rich livestock feed during times of shortage. Soil fertility to support the production of pigeon pea can be enhanced by application of fertilisers. Therefore, this study was carried out firstly, to determine the effect of phosphorus fertiliser on the growth performance and biomass production of three pigeon pea varieties, and secondly, to investigate the influence of phosphorus application on the nutrient and anti-nutrient content of three pigeon pea varieties. The field experiment was done at the University of Fort Hare research farm in Alice, South Africa. The factors investigated were three pigeon pea varieties namely Chitedze 1, Chitedze 2 and CIMMYT 1 and three phosphorus fertiliser application rates of 0, 40 and 60 kg P/ha. The study was a 3× 3 factorial experiment set up in a randomised complete block design and was replicated three times. The growth performance attributes evaluated in this study include the number of branches, plant height and root collar diameter. Root collar diameter was not significantly (p>0.05) different among the pigeon pea varieties and phosphorus levels. Likewise, the application of phosphorus was not significant (p>0.05) on plant height and the number of branches of all the varieties. However, when P level was varied, there were significant differences among the varieties, and so were the interaction (p<0.05) between variety and phosphorus on plant height and the number of branches. There was no significant (p>0.05) difference among the phosphorus levels on the fresh leaf yield of Chitedze 1 and Chitedze 2, but phosphorus application at 40 kg P/ha increased the fresh leaf yield of CIMMYT 1. Phosphorus application at 60 kg P/ha increased (p<0.05) the dry matter content of Chitedze 1 and Chitedze 2. Furthermore, the results of the trial show that the application of 40 kg P/ha and 60 kg P/ha increased (p<0.05) the dry matter yield of the varieties CIMMYT 1 and Chitedze 2, respectively. The effects of phosphorus application on the nutrient composition of the three pigeon pea varieties varied. The composition of hemicellulose of all the varieties was significantly (p<0.05) increased by the application of 40 kg P/ha. Conversely, the concentration of crude protein, phosphorus, copper and iron, and the calcium to phosphorus ratio of all the pigeon pea varieties was not significantly (p>0.05) affected by phosphorus application and there was no interactive effect of variety and phosphorus. The proximate compositions of fat, total non-structural carbohydrates, ash, neutral detergent fibre, acid detergent fibre, cellulose, neutral detergent insoluble nitrogen, acid detergent insoluble nitrogen of the pigeon pea varieties varied significantly (p<0.05) at different phosphorus application levels. There was an interactive (p<0.05) effect of variety and the level of phosphorus on the concentration of calcium (Ca), potassium (K), magnesium (Mg), sodium, zinc, manganese, and the K/(Ca+Mg) ratio. The digestible dry matter, dry matter intake and the relative feed value were significantly (p<0.05) different among the pigeon pea varieties at varying phosphorus levels. The anti-nutrient composition of Chitedze 2 was not significantly (p>0.05) affected by phosphorus application but the concentration of phenols and saponins of Chitedze 1 was significantly (p<0.05) increased when 60 kg P/ha was applied, but these anti-nutrients were reduced (p<0.05) for CIMMYT 1 at 60 kg P/ha. It can be concluded that phosphorus application influences the biomass production and chemical composition while the optimum phosphorus level vary among the pigeon pea varieties.

No description available.

Thesis (MTech (Agriculture))--Cape Peninsula University of Technology, 2014. / Plants require nitrogen (N) to support desired production levels. Nitrogen fertilization strategy is a major consideration in field management with regard to achieving both economic and environmental objectives. For instance, in potato, insufficient N supply reduces tuber size and overall yield while excessive N supply can reduce tuber quality and increase environmental risk through nitrate (NO3-) leaching and nitrous oxide emission. Selection of an adequate N fertilizer application rate for crops is difficult, due to marked variations in soil N supply and crop N demand in both the field and over time. This research was conducted to characterise the ammonium transporter gene (AMT1) of Bambara groundnut and potato using molecular biology and bioinformatics methods. Nucleotide database sequences were used to design AMT1-specific primers which were used to amplify and sequence the core-region of the gene from Bambara groundnut and potato. Bioinformatics techniques were used to predict the structure and infer properties of the proteins. Nucleotide sequence alignment and phylogenetic analysis indicate that BgAMT1 and PoAMT1 are indeed from the AMT1 family, due to the clade and high similarity they respectively shared with other plant AMT1 genes. Amino acid sequence alignment showed that BgAMT1 is 92%, 89% and 87% similar to PvAMT1.1, GlycineAMT1 and LjAMT1.1 respectively, while PoAMT1 is 92%, 83% and 76% similar to LeAMT1.1, LjAMT1.1 and LeAMT1.2 respectively. BgAMT1 and PoAMT1 fragments were shown to correspond to the 5th - 10th transmembrane spanning-domains. Mutation of Bg W1A-L and S28A (for BgAMT1) and Po S70A (for PoAMT1) is predicted to enhance ammonium (NH4+) transport activity. Residues Bg D23 (for BgAMT1) and Po D16 (for PoAMT1) must be preserved otherwise NH4+ transport activity is inhibited. In all, BgAMT1 and PoAMT1 play a role in N uptake from the root while BgAMT1 may contribute more in different steps of rhizobia interaction. In an investigation of the correlation between AMT1 gene expression levels and leaf chlorophyll content index (CCI) with plant N status, potato plants were grown in a hydroponic greenhouse with 0.75 or 7.5 mM NO3- and 0.75 or 7.5 mM NH4+ as forms of N supply in a completely randomized design. Leaf CCI as measured by chlorophyll content meter, showed that an increase in N supply results in increased leaf CCI in response to both forms of N. Total RNA was isolated from leaf sampled at 28 days after treatment and expression level of the AMT1 gene was determined by reverse transcription-qPCR using a second set of primers designed for qPCR. The results showed that expression levels of AMT1 increased from 8.731 ± 2.606 when NO3- supply was high to 24.655 ± 2.93 when NO3- supply was low. However, there was no significant response in AMT1 expression levels to changes in NH4+. This result suggested that AMT1 transports NO3- less efficiently than NH4+, and thus more transport channels are required in the cell membrane when NO3- levels are low. Such variation in AMT1 expression levels are not necessary for NH4+ transport since the transport mechanism for NH4+ is efficient even at low NH4+ levels.

Made available in DSpace on 2014-06-11T19:30:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-03-15Bitstream added on 2014-06-13T21:01:02Z : No. of bitstreams: 1 souto_ls_dr_botfca.pdf: 393414 bytes, checksum: e095c56445b4e6ededbd94233114a7e9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A utilização de resíduos urbanos na agricultura vem se tornando uma prática comum. Vários trabalhos realizados demonstram que a aplicação destes resíduos de forma adequada aumenta a produtividade das culturas e minimiza custos com fertilizantes inorgânicos. Foram realizados dois experimentos na FCA/UNESP - Botucatu, SP, em NITOSSOLO VERMELHO eutrófico, em campo e em túnel plástico. No ensaio em campo estudou-se o efeito de doses de lodo de esgoto (LE) de 0, 3, 6, 12 e 24 Mg ha-1 (base úmida) aplicados no sulco de semeadura e quatro populações de plantas (6.666, 10.000, 13.333 e 20.000 plantas ha-1), em esquema fatorial 5 x 4. Neste experimento foram avaliadas a produtividade de frutos e grãos de cachos primários e total, teor de óleo no primeiro cacho, produtividade de óleo de cachos primários e total e o teor de nutrientes nos grãos. Também se avaliou a altura média das plantas, porcentagem de grãos nos frutos e o estado nutricional por ocasião do florescimento. No ensaio em túnel plástico avaliou-se a aplicação de lodo de esgoto (LE) na superfície e incorporado em 25, 50, 75 e 100% ao volume de solo, durante o período de 50 dias de desenvolvimento da cultura, nas quantidades correspondentes a 5, 10, 20, 40 e 80 Mg ha-1, base úmida, em esquema fatorial 5 x 5. Aos 50 dias após a semeadura, as plantas de mamona foram colhidas para determinação da produção de fitomassa seca e acúmulo de macronutrientes pela parte aérea. Ambos experimentos foram conduzidos em delineamento experimental em blocos ao acaso. As quantidades aplicadas de lodo de esgoto foram calculadas em função do conteúdo e disponibilidade do nitrogênio nestes. Para o experimento de campo, a produtividade da mamoneira atingiu 2741,70 e 1972,04 kg ha-1 de frutos e grãos, respectivamente, com 24 Mg ha-1 de lodo de esgoto e, 3631,39 e 2629,39 kg ha-1 de frutos e grãos, respectivamente... / The use of urban residue in agriculture has become a usual practice. Various works show that the use of this residue in the adequate way benefits the soil properties enlarges productivity and minimizes costs with inorganic fertilizers. Two experiments were made in FCA/UNESP - Botucatu, SP, in Nitossol Red eutrophic, in field and in plastic tunnel. In the experiment in the field, we have studied the effect of levels of sewage sludge (LE) of 0, 3, 6, 12 and 24 Mg ha-1 (umid basis) applied to the sowing, into the furrows and four populations of plants (6.666, 10.000, 13.333 and 20.000 plants ha-1), in factorial scheme 5 X 4. In this experiment were evaluated the productivity of fruits and grains of primary bunch and total, oil level in the first raceme, productivity of oil in primary bunch and total and the nutrient level in the seeds. Were also evaluated the height of the plants, the seed percentage in the fruits and the nutritional state at flowering time. In the experiment in the plastic tunnel were evaluated the application of sewage sludge (LE) in the surface and incorporated in 25, 50, 75 and 100% to the volume of soil for a period of 50 days of crop development in the corresponding amounts of 5, 10, 20, 40 and 80 Mg ha-1, humid base, in factorial scheme 5 X 5. In the 50th after the sowing the castor bean plants were picked for the determination of production of dry matter and macronutrients accumulation by the aerial part. Both experiments were conducted with the use of random blocks design. The amounts of sewage sludge used were calculated considering the content and nitrogen availability in them. In the experiment in the field, the castor bean plant productivity reached 2741,70 and 1972,04 kg ha-1 of fruits and grains with 240 Mg ha-1 of sewage sludge and, 3631,39 and 2629,39 kg ha-1 of fruits and grains in the population of 20000 plants ha-1 , respectively. The oil production... (Complete abstract click electronic access below)

O uso intensivo de agrotÃxicos e fertilizantes ocasiona danos ambientais e intoxicaÃÃo humana. Em humanos, essa intoxicaÃÃo se manifesta por vÃrios sinais e sintomas. No municÃpio de Limoeiro do Norte-CE, os trabalhadores do agronegÃcio do abacaxi queixam-se de problemas de saÃde devido à exposiÃÃo aos agroquÃmicos em suas atividades laborais. O objetivo deste estudo à caracterizar os agravos à saÃde humana entre os trabalhadores do agronegÃcio do abacaxi expostos ao uso de agrotÃxico-fertilizantes quÃmicos no municÃpio de Limoeiro do Norte, localizado no Vale do Jaguaribe-CE. Trata-se de um estudo transversal, descritivo, com amostragem intencional, composta de 75 pessoas mobilizadas por redes sociais, utilizando abordagem metodolÃgica quantitativa e qualitativa. Realizou-se a aplicaÃÃo de um formulÃrio estruturado, contendo dados socioeconÃmicos, hÃbitos de vida, histÃria pregressa familiar, caracterizaÃÃo do trabalho, exposiÃÃo do trabalhador, orientaÃÃes para o trabalhador em Ãrea de uso de agrotÃxicos e medidas de controle do risco adotadas pela empresa, relaÃÃes de trabalho, caracterizaÃÃo clÃnico-toxicolÃgica, histÃria clÃnica e exame fÃsico. O processamento dos dados ocorreu no Ele info 6, versÃo 6.04 d, e a anÃlise, no Stata, versÃo 9, considerando intervalo de confianÃa de 95% e valor de P < 0,05. Pela complexidade do objeto em estudo, realizou-se abordagem qualitativa, efetivando-se uma visita a uma empresa do agronegÃcio e dois grupos focais. Para interpretaÃÃo dos sentidos atribuÃdos pelos informantes ao fenÃmeno investigado, foi realizada uma leitura aprofundada das falas nos grupos focais. A amostra à caracterizada por adultos jovens, do sexo masculino, com faixa etÃria entre 19 e 43 anos, renda familiar de 1 a 2 salÃrios mÃnimos em 80,3%. Houve negatividade de 88,0% e de 44,0% para o uso de tabaco e bebida alcoÃlica respectivamente. Cerca de 50,6% dos trabalhadores rurais entrevistados tinham mais de 13 anos de atividade laboral na agricultura e, destes, 82,6% eram assalariados, tendo de 1 a 4 anos na empresa. Entre os entrevistados, 94,6% afirmaram contato com os agrotÃxicos/fertilizantes, sendo que 56,6% consideraram ser indireto. A quase totalidade (98,6%) considerou que o contato poderia causar mal à saÃde, 68,0% nÃo souberam dizer a qual agrotÃxico foram expostos, e 48,0% a qual fertilizante. Dos trabalhadores, 64,0% afirmaram ter algum problema de saÃde, sendo que 34,7% referem de 1-4 sintomas e 18,7% entre 5 e 8 sintomas. Os problemas de saÃde relacionados a sintomas gerais foram 67,0%: 63,0% neurolÃgicos e 59,0% oculares. A cefaleia foi referida por 31,0%, e o ardor ocular, por 45,0%. Os exames de colinesterase plasmÃtica apresentaram-se todos normais; as alteraÃÃes das provas de funÃÃes hepÃticas foram de 53,0%; 13,0% de TGO, 23,5% da TGP e 14,7% de Gama GT. Para a Gama GT, foram observados valores de 107 U/L a 329 U/L em dois trabalhadores. Os valores da FA acima do normal foram em 19,0% dos exames analisados. Entre as bilirrubinas, destacou-se a BD, com 13,0% acima dos valores considerados normais. Clinicamente, foram encontradas doenÃas da pele em 28,0% da amostragem; queixas respiratÃrias em 11,0%; queixas osteomusculares em 18,0% e hipertensÃo de grau leve em 6,7%. As queixas clÃnicas associadas aos sinais e sintomas referidos e alteraÃÃes de alguns exames laboratoriais dos entrevistados sÃo de intoxicaÃÃo crÃnicas e/ou agudas. Portanto a exposiÃÃo a agrotÃxico e a fertilizantes pode causar agravos à saÃde dos trabalhadores do agronegÃcio do abacaxi em Limoeiro do Norte-CE. Estudos prospectivos visando a mensurar o impacto dos agroquÃmicos na vida dos trabalhadores e no sistema de saÃde se fazem necessÃrios. / The intensive use of pesticides and fertilizers cause environmental damage and human poisoning. In humans they can cause poisoning which is manifested by several signs and symptoms. In the town of Limoeiro do Norte-CE/BRAZIL, workers in the pineapple agribusiness area, complain about health problems due to exposure to pesticides in their activities. The objective is to characterize the human health problems among workers exposed to pineapple agribusiness uses of pesticides, chemical fertilizers, in the town of Limoeiro do Norte-CE/BRAZIL, located in the valley of Jaguaribe-CE/BRAZIL. This is a descriptive study, with purposive samples, consisting of 75 people mobilized by social networks, using the quantitative and qualitative methodology. We carried out the implementation of a structured form containing data on socioeconomic, lifestyle, family medical history, characteristics of work, worker exposure, guidelines for field workers in pesticide use area and risk control measures adopted by the company, work relationship, clinical and toxicological characteristics, medical history and physical examination. The data processing occurred in Ele info 6, version 6.04 d, and the analysis in Stata version 9. Considering confidence interval of 95% and P value <0.05. Due to the complexity of the object under study, there was a qualitative approach, resulting to a visit to an agribusiness company and two focus groups. For interpretation about the significance attributed by informants to the investigated phenomenon, we performed a thorough reading of the speeches of focus groups. The sample is characterized by young adults, male, aged between 19 to 43 years. With family incomes from 01 to 02 minimum wages by 80.3%. There was negativity of 88.0% and 44.0% for tobacco use and alcohol consumption. About 50.6% of workers surveyed said they had more than 13 years of labor activity in agriculture, and from these 82.6% were employed, with one to four years in the company. Among the respondents, 94.6% reported contact with pesticides/fertilizers, and 56.6% considered to be indirect. Almost all (98.6%) thought that contact would cause harm to health and that 68.0% could not say to which pesticides they had been exposed to and 48.0% were exposed to fertilizers. 64.0% of workers reported having some health problem, while 34.7% reported symptoms of 1-4 and 18.7% of 5-8 symptoms. Health problems related to general symptoms were 67.0%, neurological 63.0% and 59.0% eyes problems. Headache was reported by 31.0% and 45.0% for ocular burning. The tests showing plasma cholinesterase were all normal, changes in liver function tests were 53.0%, 13.0% of SGOT, SGPT of 23.5% and 14.7% of the Gamma GT. For Gamma GT, values were observed from 107 U/L to 329 U/L in two workers. The values of the FA above normal were in 19.0% of the analyzed exams. Among the bilirubins, the BD was stood out with 13.0% above the normal range. Clinically, skin disease was found in 28.0% of samples; respiratory complaints in 11.0%, 18.0% of musculoskeletal complaints and mild hypertension in 6.7%. The clinical complaints associated with signs and symptoms reported and changes in some laboratory tests by the interviewees are the chronic or acute intoxication. Therefore, exposure to pesticides and fertilizers can be detrimental to the health of workers in the pineapple agribusiness in Limoeiro do Norte-CE/BRAZIL. Prospective studies aimed at measuring the impact of pesticides on workers and on the health system are needed.