Two environmental control chamber experiments were conducted to study the effects or temperature, nitrogen, and light intensity on the growth and physiological effects on Tifgreen bermudagrass, Cynodon dactylon (L) Pers., and Cohansey bentgrass, Agrostis palustris Huds. Each of the grasses was included in a field experiment to study the influence of nitrogen rates on carbohydrate reserves at different seasons. Increased temperatures with bentgrass caused decreased carbohydrates, root weights, and final growth of tops, but increased nitrogen content and respiration. NAR in bentgrass was highest at 75 F. The respiration rate, top growth, and carbohydrate content of bermudagrass tended to increase with temperature, but root weights and NAR were highest at medium temperatures. High N generally increased top growth, NAR, respiration, and nitrogen content, but lowered the carbohydrates and root growth for both grasses. Bentgrass, grown at 95 F during the day-, declined in yield, root growth, NAR, and respiration as night temperatures increased from 60 to 90 F. With bermudagrass HAR, top growth, and root growth were highest at 75 F and lowest at 90 F night temperatures. The AEC of bentgrass were highest at the mid-temperature, but the AEC: fer bermudagrass tended to increase with the high night temperature. Low light intensity generally decreased the yield of tops and roots, NAR, respiration, and carbohydrates, but increased the nitrogen content of both grasses. Bentgrass stolons increased in carbohydrate content during the tall and early vinter, and then declined rapidly during the spring. During the summer, the carbohydrates in bentgrass were low. The carbohydrates in bermudagrass stolons decreased during the winter and spring, increased during summer, and reached a maximum by late fall. For all experiments the oligosaccharides and monosaccharides made up a rather large portion of the AEC in bentgrass, polysaccharides being the largest fraction. Polysaccharides in bermudagrass made up the largest fraction of the AEC, the monosaccharides and oligosaccharides being less than 10% of the dry weight. / Ph. D.

Lam, Shu Kee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 206-219). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (in Chinese) --- p.iv / Acknowledgements --- p.vi / Table of contents --- p.vii / List of tables --- p.xii / List of figures --- p.xvi / List of plates --- p.xvii / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- Research background --- p.1 / Chapter 1.2 --- Conceptual framework --- p.4 / Chapter 1.3 --- Objectives of the study --- p.8 / Chapter 1.4 --- Significance of the study --- p.9 / Chapter 1.5 --- Organization of the thesis --- p.10 / Chapter CHAPTER 2 --- LITERATURE REVIEW / Chapter 2.1 --- Introduction --- p.12 / Chapter 2.2 --- Use of hydroseeding in slope bioengineering works --- p.12 / Chapter 2.3 --- Problems associated with hydroseeded slopes --- p.12 / Chapter 2.4 --- Common Bermudagrass used in hydroseeding --- p.13 / Chapter 2.5 --- "Sludge disposal, potentials and problems" --- p.14 / Chapter 2.5.1 --- Properties and disposal of sludge --- p.14 / Chapter 2.5.2 --- Use of sludge and potential problems --- p.16 / Chapter 2.5.3 --- Heavy metals in sludge --- p.19 / Chapter 2.5.3.1 --- Cadmium --- p.22 / Chapter 2.5.3.2 --- Chromium --- p.22 / Chapter 2.5.3.3 --- Copper --- p.23 / Chapter 2.5.3.4 --- Nickel --- p.24 / Chapter 2.5.3.5 --- Lead --- p.24 / Chapter 2.5.3.6 --- Zinc --- p.25 / Chapter 2.5.4 --- Speciation of heavy metals --- p.25 / Chapter 2.5.5 --- Factors affecting the bioavailability of heavy metals --- p.26 / Chapter 2.5.5.1 --- Reaction pH --- p.26 / Chapter 2.5.5.2 --- Organic matter --- p.28 / Chapter 2.5.5.3 --- Fertilizers --- p.29 / Chapter 2.5.6 --- Effect of heavy metals on plant growth --- p.29 / Chapter 2.5.7 --- Effect of heavy metals on animals and water bodies --- p.31 / Chapter 2.6 --- "Lime, heavy metals and plant growth" --- p.32 / Chapter 2.6.1 --- Effect of lime on heavy metal dynamics --- p.32 / Chapter 2.6.1.1 --- Competition with heavy metals for adsorption sites --- p.32 / Chapter 2.6.1.2 --- Immobilization of heavy metals --- p.32 / Chapter 2.6.2 --- Effect of lime on plant growth --- p.34 / Chapter 2.7 --- Effect of precipitation on slopes --- p.35 / Chapter 2.7.1 --- Infiltration --- p.35 / Chapter 2.7.2 --- Surface runoff --- p.38 / Chapter 2.7.3 --- Soil erosion --- p.39 / Chapter 2.8 --- Summary --- p.42 / Chapter CHAPTER 3 --- EFFECT OF SLUDGE AND LIME ON ABOVEGROUND BIOMASS OF COMMON BERMUDAGRASS / Chapter 3.1 --- Introduction --- p.43 / Chapter 3.2 --- Materials and methods --- p.44 / Chapter 3.2.1 --- Materials --- p.45 / Chapter 3.2.2 --- Experimental design --- p.46 / Chapter 3.2.3 --- Grass clipping and pre-treatment --- p.49 / Chapter 3.3 --- Chemical analysis --- p.50 / Chapter 3.3.1 --- Properties of decomposed granite --- p.50 / Chapter 3.3.2 --- "Properties of sludge," --- p.52 / Chapter 3.3.3 --- Nitrogen of grass clippings --- p.52 / Chapter 3.4 --- Statistical analysis --- p.53 / Chapter 3.5 --- Results and discussion --- p.54 / Chapter 3.5.1 --- Properties of DG and sludge --- p.54 / Chapter 3.5.2 --- Aboveground biomass of grass --- p.56 / Chapter 3.5.3 --- Effect of sludge on aboveground biomass --- p.63 / Chapter 3.5.4 --- Effect of lime on aboveground biomass --- p.66 / Chapter 3.5.5 --- Synergic effect of sludge and lime on aboveground biomass --- p.68 / Chapter 3.5.6 --- "Effect of sludge on nitrogen uptake by grass shoots," --- p.69 / Chapter 3.6 --- Summary --- p.72 / Chapter CHAPTER 4 --- EFFECT OF SLUDGE AND LIME ON HEAVY METAL UPTAKE BY COMMON BERMUDAGRASS / Chapter 4.1 --- Introduction --- p.74 / Chapter 4.2 --- Materials and methods --- p.77 / Chapter 4.2.1 --- Materials and experimental design --- p.77 / Chapter 4.2.2 --- Analysis of heavy metals in grass shoots --- p.77 / Chapter 4.2.3 --- Reaction pH at the end of Part 1 --- p.77 / Chapter 4.2.4 --- Statistical analysis --- p.78 / Chapter 4.3 --- Results and discussion --- p.78 / Chapter 4.3.1 --- Cumulative uptake of heavy metals by common Bermudagrass --- p.79 / Chapter 4.3.2 --- Effect of sludge on heavy metal uptake --- p.84 / Chapter 4.3.3 --- Effect of lime on heavy metal uptake --- p.86 / Chapter 4.3.4 --- Synergic effect of sludge and lime on cumulative heavy metal uptake --- p.88 / Chapter 4.3.5 --- Effect of fertilizer addition --- p.91 / Chapter 4.3.6 --- Concentration of heavy metals in grass --- p.93 / Chapter 4.3.7 --- Effect of pH on heavy metal uptake --- p.98 / Chapter 4.3.8 --- Effect of heavy metal uptake on aboveground biomass --- p.100 / Chapter 4.4 --- Summary --- p.103 / Chapter CHAPTER 5 --- EFFECT OF SLUDGE AND LIME ON HEAVY METALS IN LEACHATE / Chapter 5.1 --- Introduction --- p.106 / Chapter 5.2 --- Materials and methods --- p.107 / Chapter 5.2.1 --- Leachate collection --- p.108 / Chapter 5.2.2 --- Analysis of leachate --- p.109 / Chapter 5.2.3 --- Statistical analysis --- p.109 / Chapter 5.3 --- Results and discussion --- p.110 / Chapter 5.3.1 --- Effect of sludge and lime on leachate volume --- p.110 / Chapter 5.3.2 --- Leachate pH and the effect of sludge and lime --- p.115 / Chapter 5.3.3 --- Heavy metal contents in leachate --- p.119 / Chapter 5.3.4 --- Effect of sludge and lime on the leaching of heavy metals --- p.121 / Chapter 5.3.5 --- Effect of pH on the leaching of heavy metals --- p.125 / Chapter 5.4 --- Summary --- p.126 / Chapter CHAPTER 6 --- "LEACHATE, SURFACE RUNOFF, SEDIMENT YIELD AND THEIR HEAVY METALS" / Chapter 6.1 --- Introduction --- p.128 / Chapter 6.2 --- Materials and methods --- p.130 / Chapter 6.2.1 --- Materials --- p.130 / Chapter 6.2.2 --- Experimental design --- p.132 / Chapter 6.2.3 --- Rainfall intensities in simulation experiment --- p.134 / Chapter 6.2.4 --- Selection of slope gradient --- p.136 / Chapter 6.2.5 --- Rainfall simulation --- p.136 / Chapter 6.2.6 --- "Leachate, surface runoff and runoff sediment" --- p.137 / Chapter 6.2.7 --- Properties of decomposed granite and sludge --- p.138 / Chapter 6.2.8 --- "Heavy metals in leachate, surface runoff and runoff sediment" --- p.139 / Chapter 6.2.9 --- Statistical analysis --- p.140 / Chapter 6.3 --- Results and discussion --- p.140 / Chapter 6.3.1 --- Properties of DG and sludge --- p.140 / Chapter 6.3.2 --- "Leachate, surface runoff and runoff sediment production" --- p.142 / Chapter 6.3.3 --- "Heavy metal concentrations in leachate, surface runoff and runoff sediment" --- p.153 / Chapter 6.3.3.1 --- Heavy metal concentrations in leachate --- p.153 / Chapter 6.3.3.2 --- Heavy metal concentrations in runoff --- p.163 / Chapter 6.3.4 --- Cumulative loss of heavy metals --- p.170 / Chapter 6.3.4.1 --- Cumulative loss of heavy metals from leachate --- p.170 / Chapter 6.3.4.2 --- Cumulative loss of heavy metals from runoff --- p.178 / Chapter 6.3.4.3 --- "Heavy metal loss from leachate, surface runoff and runoff sediment" --- p.185 / Chapter 6.4 --- Summary --- p.189 / Chapter CHAPTER 7 --- CONCLUSIONS / Chapter 7.1 --- Summary of major findings --- p.192 / Chapter 7.2 --- Implications of the study --- p.196 / Chapter 7.2.1 --- Potential use of sludge in slope bioengineering works --- p.196 / Chapter 7.2.2 --- Measures to optimize the benefits of sludge in land application --- p.198 / Chapter 7.3 --- Limitations of the study --- p.200 / Chapter 7.4 --- Suggestions for further study --- p.202 / REFERENCES --- p.206 / APPENDICES --- p.220

by Ngar, Yuen-ngor. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 186-196). / Chapter Chapter 1 --- Introduction Page / Chapter 1.1 --- Sludge as a waste problem --- p.1 / Chapter 1.2 --- The degraded geological environment of Hong Kong --- p.2 / Chapter 1.3 --- Use of weathered granitic material and sand as planting media --- p.3 / Chapter 1.4 --- Need of soil improvement material --- p.4 / Chapter 1.5 --- Potential for land application of sewage sludge --- p.5 / Chapter 1.6 --- Objectives of study --- p.6 / Chapter 1.7 --- Significance of study --- p.6 / Chapter Chapter 2 --- Literature Review / Chapter 2.1 --- Soil organic amendment for vegetation establishment --- p.9 / Chapter 2.2 --- Types and properties of sewage sludge --- p.10 / Chapter 2.3 --- Guidelines for land application of sludge --- p.12 / Chapter 2.3.1 --- Cation exchange capacity --- p.13 / Chapter 2.3.2 --- Zinc equivalent concept --- p.14 / Chapter 2.4 --- Effects of sludge on soil chemical and physical properties --- p.15 / Chapter 2.4.1 --- Chemical properties --- p.15 / Chapter 2.4.2 --- Physical properties --- p.18 / Chapter 2.5 --- Effects of sludge application on vegetation --- p.19 / Chapter 2.5.1 --- Germination --- p.19 / Chapter 2.5.2 --- Grass growth --- p.20 / Chapter 2.6.1 --- Choice of heavy metals for study --- p.21 / Chapter 2.6.2 --- Factors governing heavy metal availability --- p.25 / Chapter 2.6.3 --- Effects of lime on sludge-amended soil and the heavy metal availability --- p.26 / Chapter 2.6.4 --- Assessing available sludge-borne heavy metals --- p.27 / Chapter Chapter 3 --- Germination and seedling growth of bermudagrass in sludge-amended sand and CDG / Chapter 3 .1 --- Introduction --- p.30 / Chapter 3.2 --- Experimental design --- p.31 / Chapter 3.3 --- Experimental results --- p.34 / Chapter 3.3.1 --- Seed germination --- p.34 / Chapter 3.3.2 --- Seedlings and biomass growth --- p.35 / Chapter 3.3.3 --- DTPA-Extractable heavy metals --- p.39 / Chapter 3.3.4 --- Total heavy metals in plant tissue --- p.44 / Chapter 3.3.5 --- Chemical properties of the soil substrates --- p.49 / Chapter 3.4 --- Discussion --- p.54 / Chapter 3.4.1 --- Germination --- p.54 / Chapter 3.4.2 --- Nutrient effect --- p.56 / Chapter 3.4.3 --- Heavy metal availability from substrates --- p.59 / Chapter 3.4.4 --- Heavy metal uptake by the seedlings --- p.61 / Chapter 3.4.4.1 --- Metal uptake efficiency --- p.61 / Chapter 3.4.4.2 --- Amount of heavy metal uptake --- p.63 / Chapter 3.4.5 --- Textural characteristics --- p.66 / Chapter 3.5 --- Conclusions --- p.67 / Chapter Chapter 4 --- Growth and heavy metal uptake by bermudagrass grown in sludge-amended substrates / Chapter 4.1 --- Introduction --- p.70 / Chapter 4.2 --- Experimental design --- p.71 / Chapter 4.3 --- Results --- p.74 / Chapter 4.3.1 --- Biomass growth --- p.74 / Chapter 4.3.2 --- Heavy metal content of plant tissues --- p.82 / Chapter 4.3.2.1 --- Heavy metal content of the shoot --- p.83 / Chapter 4.3.2.2 --- Heavy metal content of the root --- p.89 / Chapter 4.3.3 --- Comparing the heavy metal levels in the shoot and root portions --- p.93 / Chapter 4.3.4 --- DTPA-extractable heavy metal content in soil substrates --- p.94 / Chapter 4.3.5 --- Chemical properties of the substrates --- p.100 / Chapter 4.4 --- Discussion --- p.103 / Chapter 4.4.1 --- Shoot biomass (First clipping) --- p.104 / Chapter 4.4.2 --- Shoot biomass (Second clipping) --- p.105 / Chapter 4.4.3 --- Shoot biomass ratio between the two clippings --- p.107 / Chapter 4.4.4 --- Total shoot biomass --- p.108 / Chapter 4.4.5 --- Root biomass and root: shoot ratios --- p.112 / Chapter 4.4.5.1 --- Nutrient effect --- p.113 / Chapter 4.4.5.2 --- Heavy metal phytotoxicity --- p.115 / Chapter 4.4.6 --- Total biomass production --- p.117 / Chapter 4.5 --- Conclusions --- p.118 / Chapter Chapter 5 --- Effect of lime on the growth and heavy metal uptake of bermudagrass in sludge-amended substrates / Chapter 5.1 --- Introduction --- p.121 / Chapter 5.2 --- Experimental design --- p.123 / Chapter 5.3 --- Results --- p.125 / Chapter 5.3.1 --- Biomass growth --- p.126 / Chapter 5.3.2 --- DTPA-extractable heavy metals --- p.133 / Chapter 5.3.3 --- Heavy metal uptake by the shoot portion --- p.138 / Chapter 5.3.4 --- Heavy metal uptake by the root portion --- p.147 / Chapter 5.3.5 --- Comparing metal uptake between shoot and root portions --- p.151 / Chapter 5.3.6 --- Chemical properties of substrates --- p.155 / Chapter 5.4 --- Discussion --- p.157 / Chapter 5.4.1 --- Effect of sludge and lime treatments on pH --- p.158 / Chapter 5.4.2 --- Patterns of DTPA-extractable metals and plant uptake --- p.159 / Chapter 5.4.2.1 --- Variation of heavy metal levels with liming rates --- p.160 / Chapter 5.4.2.2 --- Variation of heavy metal levels with sludge loading rates --- p.161 / Chapter 5.4.2.3 --- Bermudagrass as metal accumulator --- p.162 / Chapter 5.4.3 --- Metal uptake by the root and shoot --- p.162 / Chapter 5.4.3.1 --- Antagonistic interactions --- p.163 / Chapter 5.4.3.2 --- Parititioning of heavy metals in shoot and root --- p.163 / Chapter 5.4.4 --- Poor biomass growth --- p.166 / Chapter 5.4.4.1 --- Heavy metal toxicity --- p.166 / Chapter 5.4.4.2 --- Effect of poor soil conditions --- p.167 / Chapter 5.5 --- Conclusions --- p.177 / Chapter Chapter 6 --- Conclusions / Chapter 6.1 --- Summary of findings --- p.179 / Chapter 6.2 --- Implications of the study --- p.180 / Chapter 6.3 --- Limitations --- p.182 / Chapter 6.4 --- Suggestions for further studies --- p.184 / References --- p.186 / Appendix

Photocopy of typescript. / Digitized by Kansas Correctional Industries

Made available in DSpace on 2016-04-28T20:15:31Z (GMT). No. of bitstreams: 1 2008 - Melissa Carvalho Machado do Couto Chambarelli.pdf: 767679 bytes, checksum: 28c75b5091c80e9da0651ba953952d51 (MD5) Previous issue date: 2008-02-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The knowledge of cyathostomin infective larvae population level presents onto pasture is important to epidemiological purposes, estimating parasitic risk infection to horses and helping on setting up integrated control programs. The present study was elaborated in three parts: first is about the migratory dynamic and survival of cyathostomin infective larvae on Bermuda grass pasture for 12 months. Feces and grass samples were collected weekly at 8 a.m., 1 p.m. and 5 p.m. The samples were weighted and processed by Baermann technique. Higher survival of L3 was found at dry season, 15 and 12 weeks on feces and sward respectively, at rainy season the survival was smaller. The infective larvae were recovered during three times and the Kruskal-Wallis test did not present significance among them. At the second part, the ecology of cyathostomin infective larvae was studied for 24 months. During this period, samples of feces and grass (apex and base) were collected weekly. Samples were processed the same way as in the first part of the study. In the feces, cyathostomin L3 survived for up to 15 weeks, with higher recovery during the rainy period (46,228 kg-1.dh) and on the grass for up to 12 weeks. The recovery of L3 was greater during the dry period in the grass base (1,868 kg-1.dh) rather than in the apex (809 kg-1.dh). The L3 migration from feces to grass varied during the period. The last part of the study is about the effect of irrigation on cyathostomin infective larvae migration in Bermuda grass pasture during the four seasons of the year. Fecal masses of naturally infected horses were placed on Bermuda grass pasture at the beginning of each season. Samples of feces and grass were collected every two weeks at 8 a.m. and 5 p.m. until the end of each season from September/2007 to September/2008. Samples were processed the same way as in the first part of the study. The Kruskal-Wallis non parametric test showed a significant difference for L3 recovery in each season. The test did not present significance between the two times sampling. These results suggest that in conditions of Baixada Fluminense tropical climate horses are in permanent risk of infection. / O conhecimento do grau de contamina??o das pastagens pelas larvas infectantes de ciatostom?neos ? importante para os prop?sitos epidemiol?gicos, determinando o risco de infec??o para os eq?inos e podendo tamb?m auxiliar no estabelecimento de estrat?gias de controle integrado. O estudo foi elaborado em tr?s partes: a primeira relata o estudo da din?mica migrat?ria e a sobreviv?ncia de larvas infectantes de ciatostom?neos em pastagem coast cross durante 12 meses. Para este estudo foram coletados amostras de fezes e gram?nea com intervalos regulares de sete dias em tr?s hor?rios diferentes (8, 13 e 17 horas). As amostras foram pesadas e processadas segundo a t?cnica de Baermann. A sobreviv?ncia das L3 foi de at? 15 semanas nas fezes e 12 semanas na gram?nea no per?odo seco e de nove e oito semanas respectivamente para o per?odo chuvoso. No per?odo chuvoso, maior n?mero de L3 foi recuperado nas fezes e no per?odo seco na gram?nea. N?o foi observada diferen?a significativa entre os hor?rios de coleta pela an?lise n?o param?trica de Kruskal-Wallis. Na segunda parte experimental foi estudada a ecologia das larvas infectantes de ciatostom?neos por 24 meses. Durante este per?odo, foram realizados coletas semanais de fezes e gram?nea (?pice e base). O processamento das amostras seguiu o mesmo protocolo realizado na primeira parte do experimento. Nas fezes as L3 sobreviveram por at? 15 semanas, ocorrendo uma maior recupera??o das larvas durante o per?odo chuvoso (46.228 kg-1.ms). Na gram?nea, a sobreviv?ncia foi de at? 12 semanas. A recupera??o das L3 foi mais intensa durante o per?odo seco na base (1.868 kg-1.ms) e no ?pice (809 kg-1.ms) da gram?nea. A migra??o das L3 das fezes para a gram?nea variou durante todo o per?odo. A ?ltima parte do estudo observou a migra??o de larvas infectantes de ciatostom?neos em pastagem coast cross irrigada e n?o irrigada durante as quatro esta??es do ano. Massas fecais, de eq?inos naturalmente infectados foram depositadas nos canteiros de coast cross no in?cio de cada esta??o.A amostragem de fezes e gram?nea foi realizada quinzenalmente em dois hor?rios distintos (8 e 17 horas) at? o final de cada esta??o, no per?odo de setembro/2007 a setembro/2008. O processamento das amostras foi o mesmo descrito na primeira parte experimental. O teste n?o param?trico de Kruskal Wallis evidenciou uma diferen?a significativa na recupera??o de larvas infectantes entre as esta??es do ano. N?o foi observada uma varia??o significativa na recupera??o de L3 nos diferentes hor?rios de coleta. Os resultados sugerem que em condi??es tropicais de Baixada Fluminense, RJ os animais est?o em permanente risco de infec??o.

No description available.

No description available.

O objetivo do estudo foi avaliar produção de forragem, valor nutritivo, frações nitrogenadas e as características morfogénicas da pastagem irrigada de Cynodon spp. e adubado com nitrogênio com dose parcelada ou singular. O experimento foi conduzido na Unidade de Ensino e Pesquisa de Bovinocultura de corte da Universidade Tecnológica Federal do Paraná – Câmpus Dois Vizinhos, Sudoeste do Paraná, entre 09 de novembro de 2015 a 31 de março de 2016. A área experimental foi de 1,5 ha com pastagem de Estrela Africana (Cynodon spp.) irrigada, subdividida em 18 piquetes de áreas semelhantes, com média de 400 m2. O delineamento experimental foi inteiramente casualizado para as avaliações de produção, valor nutritivo, fracionamento protéico e as características morfogênicas da pastagem, com três tratamentos e seis repetições. Os tratamentos avaliados foram: 1A: Uma aplicação, 2A: Duas aplicações e 4A: quatro aplicações de N, com intervalos de dois pós-pastejos, totalizando a fração estabelecida de 200 kg de N ha-1. As avaliações da forragem foram determinadas diretamente através de três cortes nas condições de pré e pós-pastejo a cinco centímetros do solo, ajustadas para cada mês do ano. Para a análise da composição química, as amostras foram obtidas pela técnica de simulação de pastejo. As características morfogênicas foram obtidas pela técnica de perfilhos marcados durante o período de descanso. A taxa de acúmulo, massa de forragem pré pastejo, massa foliar, massa de colmo e material morto, apresentaram interação tratamento x mês (P<0,05). No entanto, não foram observadas diferenças significativas (P>0,05) no valor nutritivo e no fracionamento de nitrogênio total entre os tratamentos. As características morfogênicas apresentaram diferença significativa (P<0,05) para a aplicação singular e parcelada em até duas vezes. Pastagens de Cynodon spp. podem ser adubadas com 200 kg de nitrogênio por hectare em uma única dose sem interferência no valor nutritivo e sem alterações nas frações proteicas e resultados superiores nas características morfogênicas. / The objective of the study was to evaluate forage yield, nutritive value, nitrogen fractions and morphogenic characteristics of irrigated nitrogen fertilized on pasture of Cynodon spp. with split or single dose. The experiment was conducted at the Teaching and Research Unit of beef cattle breading of the Federal Technological University of Paraná, Campus Dois Vizinhos, South-West of Paraná. The experimental area was 1.5 ha with pasture of Cynodon ssp. irrigated, subdivided in 18 paddocks of similar areas, with an average of 400 m2. Experimental design was of completely randomized for the evaluation of production, nutritional value, protein fractionation and for the morphogenic characteristics, with three treatments and six repetitions. Treatments evaluated were: 1A: One application, 2A: Two applications and 4A: four applications of N, with intervals of two post-grazing, totalizing the established fraction. Forage evaluations were determined directly by three cuts in pre-and post-grazing to five cm of the soil, adjusted for each month of the year. For the analysis of chemical composition, samples were obtained by the grazing hand-plucked method. The morphogenic characteristics were obtained by the marked tills technique during the rest period. Data of accumulation rate, pregrazing forage mass, leaf mass, stem mass and dead material presented treatment x month interaction (P<0.05). However, no significant differences were observed (P> 0.05) in the nutritional value and total nitrogen fractionation between treatments. The morphogenic characteristics showed a significant difference (P <0.05) for the single and split application in two times. the pasture of Cynodon can be fertilized with 200 kg of nitrogen per hectare in single dose without interference on nutritional value and without alterations in the protein fractions and superior results in the morphogenic characteristics.

Two grazing trials and a feedlot trial were conducted with crossbred lambs to evaluate 'Quickstand' bermudagrass (Cynodon dactylon [L.] Pers.) in a cool temperate environment. Four stocking rates and two N fertilization rates (4 x 2 factorial) were replicated three times on .11-ha paddocks. Paddocks were continuously stocked with two, four, six, or eight lambs (light, moderate, heavy, and very heavy stocking rate, respectively) in grazing trial 1. Stocking rates were increased to 4, 8, 12, or 16 lambs per paddock, respectively, in grazing trial 2. In both grazing trials, paddocks were fertilized with 114 (low N) or 340 (high N) kg N ha-1yr-1 in split applications. / Master of Science

Bermudagrass (<i>Cynodon</i> spp.), when cultured at the northern limit of adaptation for semitropical grasses, is exposed seasonally to temperatures low enough to limit growth and turf quality. Research was conducted to investigate the influence of foliar iron and cytokinin applications on bermudagrass growth during fall and spring. The relationship of photosynthesis, respiration, and nonstructural carbohydrate composition to chilling temperatures was also studied. Foliar applications of Fe in late-summer and fall extended bermudagrass performance during low temperature periods of fall. Frequent Fe applications aided the retention of green bermudagrass turf during prolonged exposure to chilling temperatures. Iron applied the previous season stimulated post-dormancy recovery. Benzyladenine (BA) applied alone was not as effective as Fe for promoting green bermudagrass color retention during fall and BA had few effects on spring growth when applied the previous season. Applications of BA in conjunction with Fe were beneficial for retention of green bermudagrass color during late fall when clear plastic covers were used to prevent frost injury. A 6- to 8-week longer bermudagrass growing season occurred when clear plastic covers were used to prevent frost injury. Iron and BA did not significantly affect the total nonstructural carbohydrate (TNC) levels in Midiron bermudagrass rhizomes and stolons at the onset of dormancy in field studies. Midiron bermudagrass had higher photosynthetic and respiration rates than Tifgreen bermudagrass after 4 days exposure to chilling (10/7°C day/night) temperatures in controlled environment studies. Midiron recovered higher photosynthetic rates than Tifgreen when returned to a warm (30°C) environment after exposure to chilling temperatures. The TNC in leaves of Midiron and Tifgreen increased 88 and 160%, respectively, during 5 days at chilling temperatures. The inability to transport carbohydrate from and the subsequent accumulation of high photoassimilate levels in leaves was associated with the inability of bermudagrass to fully recover high photosynthetic rates following chilling. Reduced respiratory activity was apparently responsible for the accumulation of high TNC levels in leaves. In contrast to photosynthesis, respiration was reversibly inhibited by short term exposure of bermudagrass to chilling temperatures. Rapid recovery of high respiratory activity may be important for maintenance of aesthetically pleasing bermudagrass turf following chilling. Foliar applied Fe or BA generally caused darker green Midiron and Tifgreen turf after exposure to chilling temperatures in a controlled environment, although the enhancement of physiological activity differed with chemical applied and cultivar. Iron stimulated recovery of photosynthetic and respiratory activity in both cultivars after exposure to chilling temperatures. However, during chilling Midiron CO₂ exchange was more responsive to Fe applications. Benzyladenine increased photosynthesis in Tifgreen but not in Midiron and did not significantly affect respiration in either cultivar. Neither Fe nor BA had a consistent effect on TNC levels in bermudagrass leaves, rhizomes, or stolons. These investigations indicate that cultivar selection may play a major role in determining turf quality at chilling temperatures. Iron may modify bermudagrass physiology and enhance performance of bermudagrass exposed to chilling temperatures. / Ph. D. / incomplete_metadata