Made available in DSpace on 2016-07-18T17:51:05Z (GMT). No. of bitstreams: 1 Dissertacao Neimar.pdf: 96818 bytes, checksum: f22a08bfb199ff94007184b5d4e43964 (MD5) Previous issue date: 2008-08-28 / The aim of this work was the evaluation of production and quality of Tanzânia grass as a function of height of cut and nitrogen feeding during three cycles of cultivation. The experiment was installed in a greenhouse at UNOESTE in Presidente Prudente-SP during the period of April to October 2007. The design was random blocks with ten treatments arranged in a factorial scheme of five nitrogen doses (0, 20, 40, 80 e 160 kg ha-1) and two cutting height (20 e 40 cm). Nitrogen was applied in the cultivation cycle. The highest production of dry matter was at 20 cm of height, during the three cycles. In this cutting height dry matter was not reached by any nitrogen dose. At 40 cm the highest dry matter was reached by the high nitrogen dose. In the first cycle of cutting, nitrogen improved the number of culms at 20 and 40cm of height. In the second cycle only the height of 20cm was influenced by nitrogen doses and in the third only the 40cm cutting was influenced by the nitrogen. PB tenor was influenced by nitrogen just in the first cycle of cutting at 20 cm of height. / O trabalho objetivou avaliar a produção e a qualidade do capim Tanzânia em razão da altura de corte e adubação nitrogenada, manejada por três ciclos de cultivo. O experimento foi instalado na Casa de Vegetação da Unoeste, em Presidente Prudente-SP, durante os meses de abril/2007 a outubro/2007. Utilizou-se delineamento em blocos ao acaso, com 10 tratamentos distribuídos num esquema fatorial (5x2), cinco doses de nitrogênio (0, 20, 40, 80 e 160 kg ha-1) e duas alturas de cortes (20 e 40 cm). O nitrogênio foi aplicado por ciclo de cultivo. A maior produção de matéria seca foi obtida a 20 cm, nos três ciclos de cultivos. No corte a 20 cm a maior produção de matéria seca não foi alcançada com as maiores doses de nitrogênio. No corte a 40 cm a maior produção foi atingida com a maior dose de nitrogênio. No primeiro ciclo o nitrogênio aumentou o perfilhamento na altura de corte a 20 e a 40 cm. No segundo ciclo somente o corte a 20 cm sofreu influência do N e no terceiro ciclo apenas o corte a 40 cm sofreu influência. O teor de PB foi influenciado pelo nitrogênio no primeiro ciclo na altura de corte a 20 cm.

Thesis (PhD(Agric) (Agronomy))--University of Stellenbosch, 2005. / The response of perennial ryegrass and white clover, grown under controlled conditions, to fertiliser N rates applied under variable soil temperature (6, 12 and 18 °C), soil water potential (-10, -20, -25 and -35 kPa) and seasonal growing (June/July and October/November) conditions as well as field conditions, were evaluated. Primary- (PDM), residual- (RDM) and total dry matter (TDM) production (g pot-1) were recorded over the first- and second regrowth cycles as well as the accumulative DM production over the two regrowth cycles, respectively. Leaf N content (%) was recorded at the end of first and second regrowth cycles. Tiller/stolon numbers and root dry mass (g pot-1) were recorded at the end of the second regrowth cycle. Soil ammonium-N and nitrate-N (mg kg-1) content was monitored after fertiliser N application. Decreasing soil temperatures resulted in decreased TDM production in both crops. Only perennial ryegrass was influenced by fertiliser N rate, with a general increase in dry matter production as fertiliser N rate was increased. Ryegrass TDM production did not differ between the 100 and 150 kg N ha-1 rates but were both higher (P=0.05) if compared to the 0 and 50 kg N ha-1 treatments. Soil nitrate levels 31 days after application of 150 kg N ha–1 were still sufficient to stimulate ryegrass RDM production. The 173.8% increase in ryegrass TDM production measured at 6 °C where 150 kg N ha-1 was applied compared to the 0 kg N ha-1 treatment illustrated the ability of ryegrass to respond to fertiliser N at low soil temperatures. Soil water potential of -20 kPa resulted in higher ryegrass PDM and TDM production compared to the -25 and -35 kPa levels. White clover PDM and TDM production were however not influenced by soil water potential or fertiliser N rate. Ryegrass TDM production increased (P=0.05) as fertiliser N rates were increased. The most favourable soil water level for both ryegrass and clover root development was found to be -35 kPa. Perennial ryegrass and white clover PDM, RDM and TDM production were higher during the October/November season compared to the June/July season. Increased fertiliser N rates resulted in increased (P=0.05) ryegrass PDM and TDM production. White clover dry matter production was not influenced by fertiliser N rates. In the field study the effect of 0, 50, 100 and 150 kg N ha-1 applied as a single application either in autumn, early winter, late winter, early spring or late spring on pasture dry matter production, clover content and selected quality parameters of a perennial ryegrass-white clover pasture were investigated. Soil nitrogen dynamics in the 0-100, 200-300 and 400-500 mm soil layers were studied for 49 days following fertiliser N application. The effect of 50 kg N ha-1 on soil N dynamics was generally the same as found at the 0 kg N ha-1 applications and may therefore be regarded as a low risk treatment. The application of 150 kg N ha-1 especially in autumn and early winter showed a tendency to exceed the absorption capacity of the pasture and thereby expose fertiliser N to possible leaching and contamination of natural resources. Increased fertiliser N rate resulted in a general increase in pasture dry matter production with the highest yields recorded where N was applied in early and late spring and the lowest in early winter. The application of 150 kg N ha-1 in early and late spring resulted in the highest TDM production, however, the 50 kg N ha-1 resulted in a more efficient conversion of N applied to additional DM produced. In contrast to DM production, the clover percentage generally decreased as fertiliser N rate was increased. The effect of season of application was inconsistent. Annual trends show that the clover percentage eventually recovered to the same levels as the 0 kg N ha-1 treatments. Due to the above minimum levels recorded for most mineral and quality parameters tested it is envisaged that treatment combinations as used in this study will not be at any disadvantage to pasture and animal productivity. The study has shown that the use of fertiliser N to boost perennial ryegrass-white clover productivity and thereby minimising the negative effect of the winter gap on fodder flow management during the cool season in the Western Cape Province, may be an important management tool. Except for late spring applications, all seasons of application reduced the negative impact of the winter gap on fodder availability. It is concluded that regression lines as summarised in Tables 7.2 and 8.2 show great potential to be instrumental in developing regression models, accurately predicting the effect of fertiliser N rate on pasture performance. Other factors to be considered includes the productivity of the pasture, initial clover content, expected clover content at the end of the first regrowth cycle after fertiliser N application and the quantity of additional fodder required. Additional requirements will be to maintain and 150 kg N ha-1) in winter, as the N uptake capacity of the pasture could be exceeded and thereby increasing the risk of N leaching, resulting in environmental pollution. The N response efficiency of the pasture is also the lowest at the 150 kg N ha-1 rates, thereby reducing the profitability of these treatments.

Made available in DSpace on 2016-01-26T18:56:21Z (GMT). No. of bitstreams: 1 Danilo.pdf: 175899 bytes, checksum: b04d88ee36d5ad6d930279e979225e7f (MD5) Previous issue date: 2006-03-06 / Fundação de Amparo a Pesquisa do Estado de São Paulo / Because of depletion of the soils in south-east Brazil, Brachiaria sp. has increased its importance among cattle farmers, since it can tolerate soils with low nutrient levels. The hypothesis of this study took into account that, since Mo is a co-factor of nitrate reductase activity affecting nitrogen metabolism, different concentrations of this micronutrient could support an increase in B. brizantha growth. Therefore, the objective of this study was to verify the effects of different concentrations of Mo on physiology and yield of Brachiaria brizantha cv. Marandu, and the interaction with different N concentrations in Presidente Prudente SP, Brazil. Under simulated graze in greenhouse conditions, percentage of gross protein, dry matter production, number of shoots, and nitrate reductase activity was evaluated. Our results didn t show an expected dose-response curve in relation to Mo concentrations. However, the results indicated that Mo supplies for B.brizantha should be carried out plus nitrogen supplementation. / Com o empobrecimento dos solos da região sudeste do país, o gênero Brachiaria vem sendo um importante aliado aos pecuaristas, na condição de suportar solos com baixa fertilidade. Desta forma, este estudo tem como objetivo verificar os efeitos de diferentes doses de Mo (0, 30 ,60 ,90 g ha-1) sobre a fisiologia e produção de B. brizantha cv. Marandu, e sua interação com diferentes doses de nitrogênio (0, 40, 80 kg ha-1). Para tanto foram avaliados durante um processo de simulação de pastoreio em casa de vegetação o teor de proteína bruta, produção de matéria seca, número de perfilhos e atividade da enzima nitrato redutase. A hipótese deste trabalho considerou que, uma vez que o Mo afeta o metabolismo do nitrogênio, interferindo na atividade da nitrato redutase (NR), espera-se que diferentes doses desse micronutriente influencie o crescimento da B. brizantha cv. Marandu. Entretanto, nossos resultados não evidenciaram um clássico padrão de dose-efeito em relação ao Mo. Por outro lado, os resultados sugeriram que as suplementações com Mo em B. brizantha cv Marandu devem ser realizadas em conjunto com uma adubação nitrogenada.

Made available in DSpace on 2016-07-18T17:51:06Z (GMT). No. of bitstreams: 1 Danilo.pdf: 175899 bytes, checksum: b04d88ee36d5ad6d930279e979225e7f (MD5) Previous issue date: 2006-03-06 / Fundação de Amparo a Pesquisa do Estado de São Paulo / Because of depletion of the soils in south-east Brazil, Brachiaria sp. has increased its importance among cattle farmers, since it can tolerate soils with low nutrient levels. The hypothesis of this study took into account that, since Mo is a co-factor of nitrate reductase activity affecting nitrogen metabolism, different concentrations of this micronutrient could support an increase in B. brizantha growth. Therefore, the objective of this study was to verify the effects of different concentrations of Mo on physiology and yield of Brachiaria brizantha cv. Marandu, and the interaction with different N concentrations in Presidente Prudente SP, Brazil. Under simulated graze in greenhouse conditions, percentage of gross protein, dry matter production, number of shoots, and nitrate reductase activity was evaluated. Our results didn t show an expected dose-response curve in relation to Mo concentrations. However, the results indicated that Mo supplies for B.brizantha should be carried out plus nitrogen supplementation. / Com o empobrecimento dos solos da região sudeste do país, o gênero Brachiaria vem sendo um importante aliado aos pecuaristas, na condição de suportar solos com baixa fertilidade. Desta forma, este estudo tem como objetivo verificar os efeitos de diferentes doses de Mo (0, 30 ,60 ,90 g ha-1) sobre a fisiologia e produção de B. brizantha cv. Marandu, e sua interação com diferentes doses de nitrogênio (0, 40, 80 kg ha-1). Para tanto foram avaliados durante um processo de simulação de pastoreio em casa de vegetação o teor de proteína bruta, produção de matéria seca, número de perfilhos e atividade da enzima nitrato redutase. A hipótese deste trabalho considerou que, uma vez que o Mo afeta o metabolismo do nitrogênio, interferindo na atividade da nitrato redutase (NR), espera-se que diferentes doses desse micronutriente influencie o crescimento da B. brizantha cv. Marandu. Entretanto, nossos resultados não evidenciaram um clássico padrão de dose-efeito em relação ao Mo. Por outro lado, os resultados sugeriram que as suplementações com Mo em B. brizantha cv Marandu devem ser realizadas em conjunto com uma adubação nitrogenada.

Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Protein and oilseed production in the winter rainfall region of South Africa (primarily the Southern and Western Cape) is well below the potential for the area. One possible method of increasing production is to convince producers that the inclusion of protein and oilseed rotational crops will enhance the sustainability of wheat production systems. A project to investigate, quantify and elucidate the effect of canola (Brassica napus), lupins (Lupinus angustifolius) and medics (Medicago spp.) on subsequent wheat (Triticum aestivum) production as well as their influence on soil fertility in respect to nitrogen was initiated in 1999. The long- term rotational crop system experiment on Langgewens experimental farm near Malmesbury, provided the infrastructure for the project. During the 1999 and 2000 wheat-growing seasons, 50m2 plots were demarcated in wheat fields where wheat, lupins, canola or medics were produced in 1998 and 1999 respectively. Each plot was cleared of all vegetation and received no fertilizer N. In these fallow plots, soil samples were collected at three to four week intervals and the available nitrate-N and ammonium-N content of the topsoil (0-15cm depth) and the subsoil (15-30cm depth) were determined. Additional soil samples were also taken from the topsoil on 09/03/2000 after a summer fallow period. These samples were taken on plots that were subjected to a wheat crop in 1999, but were preceded by either wheat, canola, lupins or medics in 1998. The soil samples were then subjected to a 60-day incubation period at 15°C while being maintained at 75% of their water holding capacity. Mineral N was determined after 0, 3, 7, 15, 30, 45 and 60 days of incubation. Large variation in the nitrogen contents observed made it difficult to always obtain significant differences. The results of the soil investigations however indicate that the inclusion of lupins and medics in wheat cropping systems in the Swartland could help to limit the decline of mineral N in the soil profile, experienced within a growing season. This will therefore enable farmers to reduce fertilizer inputs without facing soil mineral N depletion. Plant samples were also collected from wheat plots during the 1999 growing season on three occasions (23/06/99 (growth stage 5), 5/08/99 (growth stage 15), 14/09/99 (growth stage 23)). Plots were selected to represent the same treatments as in the soil sampling procedure during the growing season of 1999 as described above. Plant and tiller numbers of a 0.25m2 sub sample from each plot were counted and leaf area was determined, whereafter the dry material was weighed. The percentage nitrogen content in the leaves and stems were subsequently determined using Near Infra-Red Spectroscopy. In terms of vegetative growth, little difference was observed. A significant increase in nitrogen content of wheat plants growing in plots where wheat and canala were grown in 1998 was observed in the second plant sampling (growth stage 15) and this was attributed to higher nitrogen topdressing. However, on the third sampling date on 14/9/1999 (growth stage 23), the difference was no longer evident. The most important conclusion to make from this study, is that farmers can probably save on fertilizer inputs when including lupins and medics in their wheat production systems, without risking poorer wheat growth. At growth stage 28, a 0.25m2 sub sample of wheat plants was removed at a randomly chosen point in each of the plots described above. Ears and grains were subsequently counted. The wheat remaining on the plots were then harvested at the end of October 1999 using a plot combine. Subsequently the yield, hectolitre mass, thousand grain mass and % crude protein was determined from samples of harvested grain from each plot. The % flour and % bran extraction were then determined whereafter the % flour protein was determined. Micro bread loafs were baked to estimate the loaf volume. Flour and dough properties were also tested using the Falling Number System, mixograph and alveograph. Wheat in cropping systems consisting of legume phases such as lupins and medics, required less nitrogen fertilizer application to achieve statistically the same yield, flour and dough properties. These crop rotations can therefore be considered as more ecologically sustainable and economically viable for the Swartland. This study was aimed at determining the effect of different crop rotations on soil fertility, and because clear soil fertility trends take time to form, this study was probably too short to obtain fully significant differences. / AFRIKAANSE OPSOMMING: Proteïen- en oliesaad produksie in die winter reënval streek van Suid Afrika (hoofsaaklik die Suid- en Weskaap) is ver benede die potensiaal vir die streek. Een moontlike manier om die produksie hiervan te verhoog is om produsente in hierdie streek te oortuig dat die insluiting van proteten en oliesaad gewasse die volhoubaarheid van koring verbouingstelsels sal verhoog. Na aanleiding hiervan, is In projek in 1999 van stapel gestuur om die effek van canola (Brassica napus), lupiene (Lupinus angustifolius) en medies (Medicago spp.) op daaropvolgende koring (Triticum aestivum) produksie, asook die invloed daarvan op grondvrugbaarheid in terme van stikstofinhoud, te ondersoek. Die langtermyn wisselbouproef op Langgewens proefplaas naby Malmesbury, het as infrastruktuur vir die ondersoek gedien. Gedurende die 1999 en 2000 koring groeiseisoene is 50m2 plotte in koringkampe gekies waarop koring, canola, lupiene en medies geproduseer is in onderskeidelik 1998 en 1999. Hierdie plotte is skoon gehou van plantegroei en het ook geen stikstof in kunsmisvorm gekry nie. Met drie tot vier week intervalle is grondmonsters op hierdie plotte versamel in die bogrond (0-15cm diep) en ondergrond (15-30cm diep), waarna die beskikbare nitraat-N en ammonium-N konsentrasie bepaal is. Adissionele grondmonsters van die bogrond is ook geneem op 9/03/2000 na In somer braak periode. Hierdie monsters was geneem op persele wat blootgestel was aan In koringproduksie in 1999, maar voorafgegaan is deur koring, canola, lupiene en medies in 1998. Hierdie monsters is dan vir 60 dae geïnkubeer teen 15°C en 75% van die grond se water houvermoeë. Minerale N inhoud bepalings is gedoen na 0, 3, 7, 15, 30, 45 en 60 dae van inkubasie. Groot variasie in die minerale stikstof inhoud, het die verkryging van herkenbare tendense en konstante statistiese verskille belemmer. Die resultate wat verkry is dui egter dat die insluiting van lupiene en medies in koring produksie stelsels in die Swartland, hoër minerale N vlakke in die grond handhaaf en dit kan boere gevolglik in staat stelom kunsmis insette te besnoei sonder dat grondvrugbaarheid verswak. Op 23/06/99 (groeistadium 5), 5/08/99 (groeistadium 15) en 14/09/99 (groeistadium 23) is plantmonsters versamel van koringpersele. Hierdie persele is gekies om die behandelings van die grondmonsterontledings soos hierbo beskryf, te verteenwoordig. Plante en halms van 'n 0.25m2 area uit die persele is getel en die blaaroppervlaktes is bepaal, waarna die droëmateriaal massa van die area bepaal is. Die persentasie stikstofinhoud van die blare en stingels was daarna bepaal. In terme van vegetatiewe groei was daar nie groot verskille te bespeur nie. Betekenisvolle hoër stikstof inhoud van koringblare in plotte waar daar in die vorige jaar canola en koring verbou was, is in die tweede planttrekking (groeistadium 15) gevind en dit is toegeskryf aan die hoër stikstof kopbemesting wat daardie behandelings ontvang het. Teen die derde monsterneming op 14/09l99 (groeistadium 23), was hierdie verskille nie meer in die ontledingsdata te sien nie. Die afleiding wat van hierdie studie gemaak is, is dat boere moontlik stikstofbemesting kan verminder as hulle lupiene en medies in hulle koring produksiestelsels inbring, sonder om die risiko van swakker groei te verhoog. Op 20/10/99 (groeistadium 28) is 0.25m2 plante van elke koringperseel verwyder waarna die are en die korrels getel is. Die koring wat nog op die persele was is teen die einde van Oktober 1999 met 'n perseelstropertjie geoes. Opbrengs, hektoliter massa, duidendkorrel massa en % ru-proteïene is daarna bepaal. Volgende is die % meel en % semel ekstraksie bepaal waarna die % meelproteïene bepaal is. Mikro broodjies is ook gebak om die broodvolume te bepaal. Meel en deeg eienskappe is ook getoets met die Falling Number System, mixogram en alveogram. Koring in produksiestelsels met peulplant fases (lupien en medies in hierdie geval), het minder N toediening nodig gehad om statisties dieselfde opbrengs, meel- en deeg eienskappe te verkry. Lupien en medic gebaseerde wisselbou praktyke in die Swartland kan gevolglik as meer ekologies volhoubaar en ekonomies haalbaar bestempelword. Hierdie studie het gepoog om die invloed van wisselbou op grondvrugbaarheid te ondersoek. Sodanige veranderings neem egter tyd en daarom is dit waarskynlik nog te gou om werklike grondvrugbaarheids verskille waar te neem.