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Evaluación de Chrysopogon zizanioides y la aplicación de enmienda órgano-mineral como estrategia de fitoestabilización en suelos impactados por relaves mineros / Evaluation of Chrysopogon zizanioides, and the application of an organic-mineral amendment as a phytoestabilization stretegy on soils impacted by mine wastesCuzmar Grimalt, Pablo César January 2017 (has links)
Memoria para optar al título Profesional de Ingeniero Agrónomo / En el presente estudio se evaluaron muestras de suelos impactados por un derrame de relaves mineros, ocurrido en abril de 2016, en el sector de Huechún ubicado en la comuna de Til Til, región Metropolitana. El objetivo general fue evaluar la capacidad de fitoestabilización de azufre (S), cobre (Cu) y molibdeno (Mo) con el uso de Chrysopogon zizanioides (Vetiver), establecida en un suelo impactado por relave minero, con la aplicación de una enmienda órgano-mineral, de origen comercial (Quick-Sol). Se determinaron las principales propiedades químicas de los suelos impactados y se determinó el Factor de Enriquecimiento (FE) de Cu, Mo y S como indicador de contaminación. Se estableció un ensayo con plantas de Vetiver, en macetas de 5 litros con la aplicación de la enmienda en dosis de 400 L ha-1 y 800 L ha-1. El ensayo se mantuvo durante 120 días en condiciones de invernadero y riego con agua potable.
Los resultados indican que el suelo impactado por relaves mineros registró un FE menor de Cu, una ausencia de enriquecimiento en Mo y para S el FE indicó una contaminación moderada. Después de 60 días se observó un aumento considerable en los niveles de S extraíble en suelo, probablemente debido a la oxidación de pirita presente en el relave, dicho aumento se mantuvo a los 120 días del ensayo. Para los resultados de la enmienda órgano-mineral, se observaron efectos atribuibles a ésta en el Índice de Transporte (Ti), Porcentaje de Fitoextracción (PF) y S disponible en suelo de macetas. Respecto a las plantas, para la parte aérea a los 60 días las concentraciones promedio de los tratamientos fueron: Cu 19,7 mg kg-1; Mo 1,43 mg kg-1 y S 2045 mg kg-1, a los 120 días las concentraciones promedio fueron: Cu 7,73 mg kg-1; Mo 0,43 mg kg-1 y S 1708 mg kg-1. Al ser comparadas con los niveles reportados en literatura Cu 5-20 mg kg-1 (Havlin et al., 2014); Mo <1 mg kg-1 (Kabata-Pendias y Mukherjee, 2011) y S 1400-4500 mg kg-1 (Brady y Weil, 2008), se observaron rangos normales de concentración en tejido foliar.
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Genetic diversity of Vetiver clones (Chrysopogon zizanioides and Chrysopogon nigritana) available in South Africa based on sequencing analyses and anatomical structure / Vickey DiedericksDiedericks, Vickey January 2014 (has links)
Vetiver grass or Chrysopogon zizanioides (L.) Roberty (1960) is a sterile grass which can
regenerate vegetatively from clumps of the rootstock. This, as well as its vigorous and deep
root system and flood tolerance makes it an ideal candidate for the use in soil remediation
and erosion control. In South Africa, Hydromulch (Pty) Ltd. is part of the landscape, soil
reclamation and erosion control industry. The company uses vetiver grass on a wide scale and has accumulated a collection of isolates to serve as possible germ lines for industrial
use. Due to the different approaches in environmental management as well as
environmental factors, a variety of ecotypes form during the planting and acclimatisation of
this genus. Chrysopogon nigritanus (Benth.) Veldkamp (1999), which is a native species to
Africa, is closely related to C. zizanioides and differs only slightly from C. zizanioides on a
morphological level. The major difference between the two species is that C. nigritanus is
able to seed freely and thus the use of this species should be avoided. The need arose to
screen other non-fertile plants to uncover additional genotypic variety to enable
diversification of vetiver plantings. The aim of this study was to characterise the genotype of
19 isolates of vetiver obtained from Hydromulch (Pty) Ltd. via sequencing analyses of three
DNA fragments, ITS, ndhF and rbcL. In addition, the radial root anatomy was also
investigated and compared with the genetic analyses. According to the results generated
during this study, very little or no genotypical differences exist amongst the different isolates
available from the Hydromulch (Pty) Ltd. plant collection. Only in the case of the ITS
inference were differences observed between three of the studied isolates. There was no
significant difference between the different isolates based on the root anatomy, with the
exception of two of the studied isolates which formed starch granules. / MSc (Botany), North-West University, Potchefstroom Campus, 2014
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Genetic diversity of Vetiver clones (Chrysopogon zizanioides and Chrysopogon nigritana) available in South Africa based on sequencing analyses and anatomical structure / Vickey DiedericksDiedericks, Vickey January 2014 (has links)
Vetiver grass or Chrysopogon zizanioides (L.) Roberty (1960) is a sterile grass which can
regenerate vegetatively from clumps of the rootstock. This, as well as its vigorous and deep
root system and flood tolerance makes it an ideal candidate for the use in soil remediation
and erosion control. In South Africa, Hydromulch (Pty) Ltd. is part of the landscape, soil
reclamation and erosion control industry. The company uses vetiver grass on a wide scale and has accumulated a collection of isolates to serve as possible germ lines for industrial
use. Due to the different approaches in environmental management as well as
environmental factors, a variety of ecotypes form during the planting and acclimatisation of
this genus. Chrysopogon nigritanus (Benth.) Veldkamp (1999), which is a native species to
Africa, is closely related to C. zizanioides and differs only slightly from C. zizanioides on a
morphological level. The major difference between the two species is that C. nigritanus is
able to seed freely and thus the use of this species should be avoided. The need arose to
screen other non-fertile plants to uncover additional genotypic variety to enable
diversification of vetiver plantings. The aim of this study was to characterise the genotype of
19 isolates of vetiver obtained from Hydromulch (Pty) Ltd. via sequencing analyses of three
DNA fragments, ITS, ndhF and rbcL. In addition, the radial root anatomy was also
investigated and compared with the genetic analyses. According to the results generated
during this study, very little or no genotypical differences exist amongst the different isolates
available from the Hydromulch (Pty) Ltd. plant collection. Only in the case of the ITS
inference were differences observed between three of the studied isolates. There was no
significant difference between the different isolates based on the root anatomy, with the
exception of two of the studied isolates which formed starch granules. / MSc (Botany), North-West University, Potchefstroom Campus, 2014
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Evaluación de Atriplex halimus y Chrysopogon zizanioides en la fitorremediación inducida de un suelo contaminado con plomo / Assessment of Atriplex halimus and Chrysopogon zizanioides in the induced phytoremediation of soil contaminated with leadAcuña Kohnenkamp, Edouard Jesús January 2016 (has links)
Tesis para optar al Grado de Magíster en Manejo de Suelos y Aguas / El plomo (Pb) es uno de los metales contaminantes de suelo más comunes, encontrándose ampliamente distribuido debido a actividades industriales, así como también al uso de combustibles y pinturas. En general, en suelos orgánicos el Pb se liga fuertemente a las sustancias húmicas, mientras que en suelos minerales lo hace a los óxidos de hierro, siendo más bien inmóvil en el suelo, a menos que se encuentre presente en altas concentraciones. Los efectos de la contaminación de suelos por Pb pueden ser mitigados mediante fitorremediación, una estrategia de remediación in situ que utiliza distintos componentes (plantas, enmiendas de suelo y manejos agronómicos) para remover, contener o volver inocuos los contaminantes de suelo. La mayor parte de las especies de plantas que toleran la presencia de elementos traza (ET) son de tipo excluyentes, caracterizándose por sobrevivir a través de mecanismos de restricción, almacenando los metales en paredes y vacuolas de células radicales. En el caso del Pb, la utilización de fitorremediación puede presentar inconvenientes, debido a la baja fitodisponibilidad del elemento. No obstante, para superar este inconveniente se ha propuesto la utilización de una técnica de fitorremediación inducida por agentes quelantes, la cual permite que el Pb del suelo permanezca biodisponible para las plantas.
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Infiltration-percolation sur sable et sur fibre de coco, filtres plantes et épuration d'eaux usées domestiques à dominance agroalimentaire sous climat tropical sec : cas des eaux résiduaires urbaines de Ouagadougou, Burkina Faso / Infiltration-percolation through sand and coconut fiber filters and purification plants of domestic wastewater for food dominance in dry tropical climate : case of urban waste buckets of Ouagadougou, Burkina FasoDiallo, Martine 21 December 2011 (has links)
Au Burkina Faso, l’un des soucis majeurs demeure la gestion des eaux usées et excréta. Dans l’optique de trouver une alternative à l’assainissement autonome (assainissement non collectif), des technologies biologiques rustiques par cultures fixées sur supports fins, destinées aux petites et moyennes collectivités ont été expérimentées. Le premier volet du travail expérimental à consister à évaluer les performances comparées du sable et des fibres de coco en traitement d’eaux résiduaires urbaines après un processus anaérobie par lagunage. Dans une deuxième étape, ont été évaluées les performances épuratoires de filtres plantés de Andropogon gayanus Kunth et Chrysopogon nigritana (Benth) Veldkamp deux poaceae des zones tropicales. Les abattements moyens d’élimination de la pollution biodégradable sont respectivement de 99% et 98% à la sortie du filtre à sable et de celui de substrat de coco. Cependant, il y a une DCO ajoutée due à l’extraction de composés phénoliques du substrat de coco qui occulte les performances réelles de ce support de culture. Toutefois, en l’absence d’une bonne nitrification au sein du massif de substrat de coco, contrairement au sable, nous avons relevé une élimination de l’azote sous forme d’ammonium avec un rendement de 75%. Par ailleurs, ce matériau végétal par sa structure très poreuse a montré une plus grande capacité à éliminer les sels minéraux comparativement au sable. Quant aux filtres plantés de Andropogon gayanus et Chrysopogon nigritana, si les deux pilotes ont assuré des abattements de plus de 97% de la DBO5, le premier a assuré un prélèvement plus important des nutriments (N et P). / In Burkina Faso, wastewater and excreta management in the urban and rural areas remains a big concern. In order to find an alternative to on-site sanitation by the exclusive use of excreta collecting system without treatment, extensive biological processes of wastewater treatment have been experimented. At first, the comparative performances of two materials (sand and coconut fibers) were evaluated in wastewater treatment. An anaerobic pond served as the primary treatment. Then in a second step, Andropogon gayanus Kunth and Chrysopogon nigritana (Benth) Veldkamp, two tropical Poaceae, were used to treat municipal wastewater by constructed wetlands. As results, average yields of eliminating biodegradable pollution were respectively 99% and 98% for the sand filter and the coconut fibers. However, there is an added COD due to the extraction of phenolic compounds contained in the coconut fibers. This masks the real performance of this material on the COD removal. Moreover, without good nitrification in coconut substrate, a removal of nitrogen in ammonium form with a yield of 75% was founded. Thanks to its very porous structure, coconut fibers showed a greater ability to remove minerals compared to sand. The two constructed wetlands have shown good removal efficiencies of organic pollution with values above 97% of BOD5. This was enhanced by the alternating phases of feeding and resting. For nutrients, the filter planted with Andropogon gayanus provided an important removal of N and P. Chrysopogon nigritana showed the drought resistance to evapotranspiration.
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Regeneration Ecology of Chrysopogon aucheri and Cymbopogon jwarancusa in Grasslands of Upland Balochistan , PakistanAhmad, Sarfraz 01 May 1998 (has links)
Field experiments were conducted to investigate the seed attributes, movements and fates of dispersal units, and seedling establishment of Chrysopogon aucheri and Cymbopogon jwarancusa in a representative grassland ecosystem in upland Balochistan, Pakistan.
Cymbopogon jwarancusa had more filled and viable caryopses than Chrysopogon aucheri. Seeds (spikelets) of both species had similar morphological features. Chrysopogon aucheri had one dispersal unit, a triplet spikelet. Cymbopogon jwarancusa had four types of dispersal units: a paired spikelet, a partial raceme, an entire raceme, and a partial inflorescence comprised of two racemes.
Paired spikelets and partial racemes of Cymbopogon jwarancusa had greater mean dispersal distances (94 and 101 cm) from the edge of the basal crown of marked plants to the ground surface than triplet spikelets of Chrysopogon aucheri (79 cm). Spikelets of Cymbopogon jwarancusa and Chrysopogon aucheri moved mean distances of 26 and 32 cm, respectively, on the ground surface before becoming trapped in a microhabitat. The mean angle of dispersal for both species was toward the northeast, according to the prevailing wind direction. An ant (Tica verona) was the only detected seed (spikelet) predator for Chrysopogon aucheri. Both species had a weakly persistent soil seed bank, with higher amounts of seeds found under plant canopies compared to open interspaces.
The recruitment of Chrysopogon aucheri and Cymbopogon jwarancusa seedlings from the natural seed bank was monitored in seven different microhabitats under natural and above-normal precipitation regimes . Above-normal precipitation increased seedling recruitment for both species in all microhabitats. Cymbopogon jwarancusa had higher seedling densities than Chrysopogon auchfiri. Seedling survival and tiller development for both species were greatest in the gravel microhabitat in the natural precipitation treatment. Monsoon rains in late July enhanced emergence of both species from recently dispersed seeds but emerged seedlings did not survive to the end of the growing season.
The field studies indicate that Cymbopogon jwarancusa has a greater regeneration potential than Chrysopogon aucheri in this grassland ecosystem in upland Balochistan. It may be difficult to increase the composition of Chrysopogon aucheri, the more desirable species in these grasslands, when using management techniques that rely on natural regeneration .
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Infiltration-percolation sur sable et sur fibre de coco, filtres plantes et épuration d'eaux usées domestiques à dominance agroalimentaire sous climat tropical sec : cas des eaux résiduaires urbaines de Ouagadougou, Burkina FasoDiallo, Martine 21 December 2011 (has links) (PDF)
Au Burkina Faso, l'un des soucis majeurs demeure la gestion des eaux usées et excréta. Dans l'optique de trouver une alternative à l'assainissement autonome (assainissement non collectif), des technologies biologiques rustiques par cultures fixées sur supports fins, destinées aux petites et moyennes collectivités ont été expérimentées. Le premier volet du travail expérimental à consister à évaluer les performances comparées du sable et des fibres de coco en traitement d'eaux résiduaires urbaines après un processus anaérobie par lagunage. Dans une deuxième étape, ont été évaluées les performances épuratoires de filtres plantés de Andropogon gayanus Kunth et Chrysopogon nigritana (Benth) Veldkamp deux poaceae des zones tropicales. Les abattements moyens d'élimination de la pollution biodégradable sont respectivement de 99% et 98% à la sortie du filtre à sable et de celui de substrat de coco. Cependant, il y a une DCO ajoutée due à l'extraction de composés phénoliques du substrat de coco qui occulte les performances réelles de ce support de culture. Toutefois, en l'absence d'une bonne nitrification au sein du massif de substrat de coco, contrairement au sable, nous avons relevé une élimination de l'azote sous forme d'ammonium avec un rendement de 75%. Par ailleurs, ce matériau végétal par sa structure très poreuse a montré une plus grande capacité à éliminer les sels minéraux comparativement au sable. Quant aux filtres plantés de Andropogon gayanus et Chrysopogon nigritana, si les deux pilotes ont assuré des abattements de plus de 97% de la DBO5, le premier a assuré un prélèvement plus important des nutriments (N et P).
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Desempenho e influência dos capins tifton 85 (Cynodon sp.) e Vetiver (Chrysopogon zizanioides) no tratamento de esgoto sanitário em sistemas alagados construídos / Performance and influence of Tifton 85 (Cynodon sp.) and vetiver (Chrysopogon zizanioides) grasses in the treatment of sanitary sewage in constructed wetlandsJesus, Fernanda Lamede Ferreira de 24 March 2016 (has links)
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Previous issue date: 2016-03-24 / Fundação de Amparo à Pesquisa do Estado de Minas Gerais / No presente trabalho, procurou-se avaliar o desempenho de uma espécie de raízes fasciculadas (capim-vetiver) e outra estolonífera (capim-tifton 85), quando cultivadas em sistemas alagados construídos de escoamento horizontal subsuperficial (SAC- EHSS), no tratamento do efluente primário de esgoto sanitário. Para avaliação da influência da presença e do sistema radicular das plantas, foram utilizados três leitos, um plantado com capim-tifton 85 (SAC-EHSST), outro com capim-vetiver (SAC- EHSSV), com 12,5 propágulos por m², sendo o terceiro mantido sem plantas. Os SACs-EHSS foram construídos em paralelo, com fundo concretado e laterais em alvenaria, cobertos com lona de 2 mm de espessura. Como substrato, foi utilizada a brita gnáissica # 0, de diâmetro D60 igual a 7,0 mm, Coeficiente de Uniformidade (D60 /D10) de 1,6 e volume de vazios de 48,4 %, preenchido até a altura de 0,25 m. Cada SACs-EHSS, de área superficial de 4 m² e volume molhado (volume do substrato de preenchimento dos SACs-EHSS em contato com o esgoto sanitário em tratamento) de 1 m³, foi alimentado com vazão na faixa de 0,53 a 0,80 m³ d^-1, correspondente à de uma taxa de carregamento orgânico (TCO) de, aproximadamente, 350 kg ha^-1 d^-1 de DBO. Essa vazão proporcionou um tempo de detenção hidráulica (TDH) teórico entre 0,6 e 0,9 dias. Para avaliar o desempenho dos sistemas, foram efetuadas dez amostragens da água residuária afluente e efluente de cada SAC, no decorrer do período experimental, medindo-se a condutividade elétrica (CE), turbidez e o pH e quantificando-se as concentrações de DBO, DQO, SST, N-total, P-total, K e Na. Os valores foram corrigidos considerando-se as perdas de água por evaporação/evapotranspiração nos SACs-EHSS. Para a quantificação da produtividade de matéria seca e dos teores de N-total, P-total, K e Na no tecido vegetal, foram efetuados seis cortes da biomassa aérea das espécies vegetais cultivadas nos SACs-EHSS. No final do período de monitoramento, foram feitas escavações no meio suporte, para medição da profundidade atingida pelas raízes das plantas no substrato de preenchimento dos SACs-EHSS, além de serem quantificadas a massa e o volume ocupado pelas raízes das plantas, bem como seus teores de N-total, P-total, K e Na. De modo geral, as espécies avaliadas se adaptaram bem ao cultivo em SACs-EHSS utilizados no tratamento de esgoto sanitário, considerando- se a TCO aplicada. No substrato, foi observado maior volume, massa e profundidade das raízes do capim-vetiver, dando indícios de sua melhor adaptação e adequação a esse SAC-EHSS, comparativamente ao cultivado com o capim-tifton 85. O capim-tifton 85 mostrou-se capaz de remover mais Na em sua biomassa aérea que o capim-vetiver (p > 0,05), no entanto, em função de sua maior produtividade, houve tendência de maior remoção de N, P e K pelo capim-vetiver. A estação climática da primavera proporcionou maior remoção de nutrientes/poluentes pelas espécies vegetais avaliadas. Os SACs-EHSS cultivados e o não cultivado se mostraram eficientes na remoção da turbidez, SST, DBO, DQO e N-total o, apresentando, no entanto, relativamente baixas remoções de P, K e Na do esgoto sanitário. A unidade não cultivada apresentou desempenho semelhante (p < 0,05) à obtida nos SACs- EHSS plantados, no que se refere à remoção de DQO, N-total e K, porém foi menos eficiente que o SAC-EHSSV na retenção de SST, DBO e turbidez. Os resultados obtidos no presente trabalho indicaram que o capim-vetiver, representante do grupo de espécies vegetais de sistema fasciculado, apresentou melhor desempenho na remoção de poluentes do esgoto sanitário que o capim-tifton 85, representante de espécies estoloníferas. Possivelmente, o maior volume e alcance, em termos de profundidade, das raízes fasciculadas é que explicam as maiores remoções obtidas no SAC-EHSSV. / This study aimed to evaluate the performance of a species of fasciculate roots (grass vetiver) and other stolon root system (grass tifton 85) when cultivated in constructed wetland of horizontal subsurface flow (CW-HSSF), in the treatment of primary effluent sanitary sewage. To evaluate the influence of the presence and root system of the plants three beds were used, a planted with Tifton 85 (CW-HSSFT), another with vetiver grass (CW-HSSFV), with 12.5 propagules per m² and the third kept without plants. The CWs were constructed in parallel with bottom and of concrete and sides of masonry, covered with 2 mm thick of plastic blanket. As substrate (of filling) of the CW-HSSFs was used gravel gneissic # 0 (diameter -D60 = 7.0 mm, coefficient of uniformity D60/D10 = 1.6 and void volume of 48.4%, which was a layer of 0.25 m thick. Each CW-HSSF, having surface area of 4 m² and wet volume (volume filling substrate CW-HSSF in contact with the sewage in treatment) of 1 m³ was fed with a flow rate in the range of 0.53 to 0.80 m³ d ^-1, corresponding to an organic loading rate (OLR) of, approximately, 350 kg ha^-1 d^-1 of BOD. This flow rate provided a theoretical hydraulic retention time (HRT) between 0.6 and 0.9 days. To evaluate the performance of systems were made ten samples of wastewater influent water and effluent from each CW-HSSF, during the experimental period, to measure the electrical conductivity, turbidity and pH and quantify the concentrations of BOD, COD, TSS, total N, total P, K and Na. The values were corrected considering water losses by evaporation/evapotranspiration in CWs-HSSF. It was also done six cuts in the biomass of plant species, for the quantification of dry matter productivity and contents of total N, P, K and Na in the plant tissue. At the end of the monitoring period, excavations were made in the substrate of the CWs-HSSF, for depth measurement achieved by plant roots, quantify the mass and volume occupied by the roots, and the N-total, total-P, K and Na content. In general, the assessed species have adapted well to cultivation in CW-HSSF used to treat sanitary sewage, considering the OLR applied. In the substrate, there was a higher volume, mass and depth of fasciculate roots of vetiver grass indicates the better adaptation and adequacy of this grass, compared to the grass tifton 85 in CW-HSSF. The Tifton 85 grass proved to be able to remove more Na in its above ground biomass that vetiver grass (p > 0.05), however, due to its higher productivity, a trend towards greater removal of N, P and K by vetiver grass. The spring weather station provided greater removal of nutrients/pollutants by plant species evaluated. Cultivated CW-HSSF and uncultivated were efficient in the removal of turbidity, TSS, BOD, COD, Total-N, presenting, however, relatively low removal of P, K and Na of the sanitary sewage. The unit uncultivated showed similar performance (p < 0,05) to the CWs-HSSF planted as regards the removal of COD, total-N, and K, but was less efficient than CW-HSSFV retention TSS, BOD and turbidity. The results obtained in this study indicated that the vetiver grass, representative group of fasciculated plant species system performed that have better performance in removing sewage polluting the Tifton 85, representative of stoloniferous species. Perhaps the greatest volume and range, in terms of depth, of fasciculate roots is that explain the largest removals observed by CW-HSSFV.
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Autecological Characteristics of Chrysopogon aucheri and Cymbopogon jwarancusa, Dominant Rangeland Grasses in BaluchistanSaleem, Mohammad 01 May 1990 (has links)
Controlled environment experiments were designed to study the germination, seedling development, and defoliation responses of Chrysopogon aucheri and Cymbopogon jwarancusa to better understand their xv autecology and potential use in range improvement programs in Baluchistan.
In experiment 1, Cymbopogon jwarancusa had greater seed fill and viability than Chrysopogon aucheri. When incubated at six different alternating temperature regimes, seeds of Cymbopogon jwarancusa had greater cumulative germination at five temperature regimes and faster germination at the colder temperature regimes than Chrysopogon aucheri.
In experiment 2, seedling shoot and root development was characterized at 15-day intervals over a 60-day period. Seedlings of both species had a "panicoid'' type seedling morphology. Chrysopogon aucheri and Cymbopogon �warancusa developed comparable numbers of leaves and tillers per plant during the 60-day period. Chrysopogon aucheri had a greater number, length, and dry weight of primary and seminal roots than Cymbopogon jwarancusa at 30 and 60 days, respectively. Adventitious root length was also higher for Chrysopogon aucheri than Cymbopogon jwarancusa at 60 days. Seedlings of both species had similar shoot:root ratios and relative growth rates. In experiment 3, seedlings of both species were planted in rnonocultures and in a 50:50 mixtures. Defoliation treatments, implemented 32 weeks after emergence, included: equally clipping all plants of both species zero, one, two, or three times (at 4-week intervals) in monoculture and mixture; and clipping one species zero, one, two, or three times (at 4-week intervals) without clipping the associated species in mixture. Both species remained vegetative and did not differ in leaf and tiller development until about 32 weeks after emergence. During later growth, Chrysopogon aucheri reproduced while Cymbopogon jwarancusa remained vegetative. cymbopogon jwarancusa produced more tillers on control plants and defoliated plants (mainly in monoculture). At lower frequencies of defoliation Chrysopogon aucheri produced more shoot and root biomass than Cymbopogon jwarancusa (mainly in mixture). In 50:50 mixtures when one species was defoliated and the other not, both species were comparable in shoot dry weight; however, Chrysopopgon aucheri was superior to Cymbopogon jwarancusa in root dry weight at all defoliation regimes. The initial standing crop and subsequent regrowth of Chrysopogon aucheri were comparable or higher in crude protein and digestibility than Cymbopogon jwarancusa.
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Comportamento do capim-vetiver (Chrysopogon zizanioides (L.) Roberty) como contribuição na estabilização de talude da margem Rio São Francisco / Behavior of vetiver grass (Chrysopogon zizanioides (L.) Roberty) as a contribution in stabilization in the slope margins São Francisco RiverMachado, Lorena 19 February 2014 (has links)
The changes in the hydrological regime in the São Francisco River basin, due to the implementation of hydroelectric power dams, are causing low water levels and therefore the bank erosion promoted by the riverbank undercutting. These changes, along with deforestation of riparian vegetation require economically viable and efficient measures since been affecting the population of the Lower São Francisco. The objective of this study was to evaluate the behavior of the root system of vetiver grass (Chrysopogon zizanioides) in ordet o evaluate its ability to restructuring physical soil mechanics and suitability to the process of stabilization of erosion of banks, as well as evaluate its effect on the soil penetration resistance (PR). To evaluate the influence of the grass on soil shear strength Root Density (RL), the Root Length Density (RLD), the Root Area Ratio (RAR), the Root Tensile Strength (TR) and the Root Cohesion (CR) were measured. The results were subjected to analysis of variance (p <0.05) using the SISVAR and then was held the polynomial regression analysis. To evaluate the RP, sampling was carried out near vetiver grass cultivation and the rows between crops along the profile until a depth of 0.60 m. The soil water was determined by weighing method, the RP by an automated penetrometer, the particle-size analysis by densitometry and root density by the monolith method. The results of RP, moisture and root density were subjected to analysis of variance (p <0.05) and afterwards the means were compared by Tukey test using the software SISVAR. For DR, DCR and RAR layer 0-0.10 m showed higher results which yielded 4.84 kg m-3, 12.45 km m-3, 1.66%, respectively. While the average result of TR was 83 MPa and CR 528 kPa. The vetiver grass near points had a mean RP of 1793.94 kPa and average soil water of 11.78%, differing from the sampled points in the rows between crops. The PR and soil moisture were not statistically different throughout the depths. The vetiver grass promoted ground cover, favoring a higher water retention and consequently decreasing the RP, as well as helping to increase the soil shear strength, giving a very important contribution to slope stabilization. / As alterações do regime hidrológico na bacia hidrográfica do Rio São Francisco, devido à implantação da cascata de hidrelétricas, estão causando baixos níveis de água e consequentemente erosão nos taludes do rio pelo solapamento da sua base. Essas alterações, juntamente com o desmatamento da mata ciliar requerem medidas economicamente viáveis e eficientes, visto que vêm afetando a população do Baixo São Francisco. Esse estudo teve como objetivo avaliar o comportamento do sistema radicular do capim-vetiver (Chrysopogon zizanioides) quanto à capacidade de reestruturação físico-mecânica do solo e à adequação ao processo de estabilização da erosão dos taludes, assim como avaliar o seu efeito na resistência do solo à penetração (RP). Para avaliar a influência da gramínea na resistência ao cisalhamento do solo, foram mensuradas a Densidade Radicular (DR), a Densidade do Comprimento Radicular (DCR), a Razão de Raiz por Área (RAR), a Resistência de Raízes à Ruptura (TR) e a Coesão da Raiz (CR). Os resultados foram submetidos à análise de variância (p<0,05) utilizando o SISVAR e em seguida realizou-se a análise de regressão polinomial. Para avaliar a RP, foram realizadas amostragens em pontos localizados próximos ao capim-vetiver e nas entrelinhas de cultivo, ao longo do perfil até a profundidade de 0,60 m. O teor de umidade foi determinado por pesagem, a RP por um penetrômetro automatizado, a análise granulométrica por densimetria e a densidade de raízes pelo método do monólito. Os resultados da RP, da umidade e da densidade de raízes foram submetidos à análise de variância (p<0,05) e posteriormente as médias foram comparadas pelo teste de Tukey usando o software SISVAR. Para DR, DCR e RAR, a camada de 0-0,10 m apresentou maiores valores com 4,84 kg m-3, 12,45 km m-3, 1,66%, respectivamente. Enquanto que o resultado médio de TR foi de 83 MPa e o de CR de 528 kPa. Os pontos próximos ao capim-vetiver apresentaram RP média de 1793,94 kPa e umidade média de 11,78%, diferindo estatisticamente dos pontos amostrados nas entrelinhas de cultivo. A RP e a umidade do solo não diferiram estatisticamente nas profundidades. O capim vetiver promoveu a cobertura do solo, favorecendo a maior retenção de água e, consequentemente, diminuindo a RP, além de favorecer o aumento da resistência ao cisalhamento do solo, auxiliando na estabilização de taludes.
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