Grasses are widely used in revegetation to control erosion, build soil and maintain habitat. In northeast British Columbia, non-native grass species are commonly seeded to reclaim industrially disturbed sites. Widespread concern about degradation of biodiversity and key ecological processes has led to increasing value placed on native species and management practices leading to a more resilient landscape. I undertook this study to fill the restoration knowledge gap relating to native grasses in northeast BC. I did an extensive inventory of grasses on 217 sites in 2007, 2008 and 2009. Functional traits were measured in the field and in a greenhouse growth experiment. I found ninety-nine grass species occuring in the region, 70% of which are native. The number, proportion and extent of non-native grasses are increasing and four of these – Poa pratensis, Festuca rubra, Bromus inermis, and Phleum pratense represented almost a quarter of all occurrences. Several native species were common throughout the region: Calamagrostis canadensis, Leymus innovatus, Elymus trachycaulus, Poa palustris and Agrostis scabra. Other native species, including Festuca altaica, Koeleria macrantha, Pascopyrum smithii, and Schizachne purpurascens, strongly favoured intact habitats. Elevation, soil moisture regime, proportion of bare ground, and land use were significant factors related to local grass species composition and abundance. Agrostis scabra, Alopecurus aequalis, Beckmannia syzigachne, Bromus ciliatus, Cinna latifolia, Deschampsia cespitosa, Elymus alaskanus, Elymus trachycaulus, Festuca saximontana and Hordeum jubatum grew commonly on severely damaged well sites. Field measurements for Specific Leaf Area (SLA) and Leaf Dry Matter Content (LDMC) of 11 species showed an inverse correlation. Bromus ciliatus, Bromus pumpellianus, and Elymus trachycaulus had high SLA/low LDMC linked to rapid growth, whereas Festuca altaica, Deschampsia cespitosa, and Calamagrostis stricta had low SLA/high LDMC linked to slow growth and persistence. In the greenhouse experiment, Poa palustris, Cinna latifolia and Bromus ciliatus produced the most overall biomass and Pascopyrum smithii and Poa palustris produced the greatest aboveground biomass. Calamagrostis stricta, Poa palustris, Elymus glaucus, Leymus innovatus and Pascopyrum smithii exhibited clonal growth. Beckmannia syzigachne, Bromus ciliatus Cinna latifolia produced viable seed during the 135-day experiment. Considering all attributes five native species, Calamagrostis canadensis, Elymus trachycaulus, Poa palustris, Leymus innovatus, and Agrostis scabra are recommended for general restoration use in northeast B.C. Other native species show promise when matched to particular site conditions, including Alopecurus aequalis, Arctagrostis latifolia, Beckmannia syzigachne, Bromus ciliatus, Calamagrostis stricta, Cinna latifolia, Deschampsia cespitosa, Elymus glaucus, Festuca saximontana, Glyceria striata, Hordeum jubatum, Koeleria macrantha, Pascopyrum smithii, Poa alpina, Schizachne purpurascens and Trisetum spicatum. This information will be valuable to land managers interested in moving beyond reclamation to ecological restoration of sites disturbed by oil and gas development. Developing practices that are environmentally sound and socially acceptable requires ongoing botanical inventory. Plant traits may be useful in matching species to site conditions and restoration goals. Policy recommendations include phasing in of requirements to use native seed while restricting the use of agronomic species, promoting natural colonization, and supporting a native seed industry.

Proportional loss models commonly used in disease surveys are based on the assumption that per cent yield loss is the same in all crops, regardless of their yield potential. Estimates of regional crop loss may be inaccurate if the relationship between disease and yield loss is affected by crop yield potential. The importance of crop yield potential in disease: yield loss modelling was investigated and models for more accurate regional crop loss estimates were developed, taking crop yield potential into account. Two spring sown barley (cv. Triumph) experiments were conducted in 1987/88 and 1988/89 in Canterbury, New Zealand, to study the effect of crop yield potential on the relationship between disease and yield loss. Crop yield potentials of 323 to 806gDM/m² were generated in seven crops by varying nitrogen and water inputs, sowing date (mid-spring and early-summer) and season. Leaf rust (Puccinia hordei Otth) epidemics of different severity were generated by applying fungicides at different times, frequencies and rates to control the natural epidemics. Disease was measured as per cent disease severity (%DS), green leaf area, radiation interception and near-infrared radiation (NIR) reflectance from crop canopies. Yield was measured as total and grain dry weight. Epidemics were severe in the fully diseased plots from GS 34 and 46 to maturity in the late and early sown crops respectively. Disease reduced grain yield by 50 to 63% in 1987/88 and 24 to 38% in 1988/89 in the fully diseased plots. Disease: yield loss models were derived by regression analysis for each crop in 1987/88. Single point, multiple point and area under curve models were derived from %DS and GLAI variables, and proportional (%) and actual (gDM/m²) grain yield. The effect of yield potential was determined by comparing regression equation coefficients for each crop with crop yield potential. An area under green leaf area index curve (AUGLAIC): actual yield model was best suited to determining the effect of yield potential on yield loss. This model was selected because AUGLAIC summarised the effect of disease on plant growth over the season and actual yield represented the crop yield potential in the absence of disease and the response of actual yield to disease. Crop yield potential did not affect actual yield loss caused by leaf rust. Disease measured as AUGLAIC explained most of the variation in yield (R²adj=0.93) for all crops in both years. Assessment of GLAI is not suitable for estimation of regional crop loss because of the requirement for a rapid and low cost method. Reflectance of NIR from the crop canopy was investigated as an alternative to GLAI measurements. Reflectance was correlated significantly (P<0.001) with GLAI (r=0.66 to 0.89) and green area index (r=0.76 to 0.92). Reflectance measured at grain-filling (GS 85-87) explained most (R²adj=0.94) of the variation in yield for all crops in both years. The relationship between AUGLAIC and yield was validated with data from independent diseased and healthy barley crops. The AUGLAIC: yield model described the effects of disease on yield accurately but overestimated yield by 49 to 108% in the healthy crops. Models based on accumulated PAR (photosynthetically active radiation) intercepted by green leaves explained the observed deviations in yield of these crops from the AUGLAIC: yield model. Accumulated PAR models accounted for differences in incident radiation, canopy structure, radiation interception by green leaves, radiation use efficiency and harvest index which are important in determining dry matter production and grain yield. Accumulated PAR models described the effects of disease on crop growth which were not represented by GLAI alone. Variation in crop yield potential at the regional scale is important in disease: yield loss modelling and can be accounted for by using either separate equations for each yield potential crop or crop category, robust models, inclusion of a form function for yield potential or choice of disease and yield variables which integrate yield potential.

Thesis (MScFor)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: In South Africa fertilizer applications at establishment is a common practice in the forestry industry. Recommendations are based on past research with conventional sources (CV) and as a result there have only been slight improvements in additional plantation production over recent years. The objective of this study was to investigate initial stand responses in terms of leaf are index (LAI), foliar nutrient content, biomass index (BI) and volume growth to the application of controlled release fertilizers (CRF) at re-establishment. Nitrogen (N), phosphorus (P) and potassium (K) were applied in a three way factorial combination to Pinus radiata at planting on a site in the Western Cape. The design was replicated five times across the study area. N (CRF) and P (CV) were applied in a two way factorial combination at planting to two Eucalyptus grandis x urophylla hybrids and Eucalyptus dunnii across three sites, one ex-agricultural and two re-establishment sites, on the Zululand coastal plain and the Midlands region. The design was replicated nine times on each study site. Harvesting residues were burnt on the eucalypt sites prior to establishment and may have had an impact on the responses found. An outbreak of Fusarium circinatum on the P. radiata site resulted in unexpected and extremely variable responses. An attempt to quantify the effect of the disease had limited success. The mean BI of the control treatment reached 25. The best CV and CRF treatments yielded improvements of 42 % and 83 % in BI over the control respectively, with only the CRF treatment difference being significant. Foliar analysis results revealed marginal to deficient concentrations of P and Mg being alleviated by the treatments in question. On the KZN Zululand sites there was a marked response of the hybrids to N with P having an additive effect on volume growth, LAI and foliar N content. Application of 120 g N and 20 g P per tree on the ex-agriculture site produced a volume of 8 m3 ha-1 at one year of age, a significant increase of 118 % and 80 % over the control and best CV treatment respectively. Application of 80 g N and 20 g P per tree, on the re-establishment site, yielded a volume of 24.6 m3 ha-1 at one year which equates to a significant 39 % and insignificant 7 % additional volume at one year over the control and best CV treatment respectively. A non-significant suppressive effect was found with 20 g CV P application only. At the KZN Midlands site, the major early response in height were to P application. Applications of 20 g CV P per tree, resulted in a mean height of 162.6 cm at seven months of age, a significant 28 % higher than the control. There was no significant effect of 80 g CRF N and 20 g CV P per tree respectively. CRF N applications up to 120 g per tree provide additional growth over recommended CV applications on coastal Zululand sites with low organic carbon (OC) content. On the KZN Midlands site with higher OC and clay content, early responses were limited to P fertilization only regardless of the fertilizer source. / AFRIKAANSE OPSOMMING: Dit is algemene praktyk in die Suid Afrikaanse bosbou industrie om kunsmis tydens aanplanting toe te dien. Hierdie aanbeveling is gebasseer op navorsing resultate met konvensionele bronne (CV), gevolglik was slegs ‘n klein toename in bykomende plantasie produksie gemeet die afgelope paar jaar. Die doelwit tydens hierdie studie is om die aanvanklike reaksie van die bome in terme van blaar oppervlak indeks (LAI), blaar-voedingstof inhoud, biomassa indeks (BI) en volume op die toediening van beheerde vrylating kunsmis (CRF) tydens aanplanting vas te stel. Stikstof (N), fosfor (P) en kalium (K) is in drie-ledige kombinasie aan Pinus radiata op ’n plantasie in die Weskaap toegedien. Die ontwerp is vyf keer in die studiegebied herhaal. N en P is in twee-ledige kombinasie aan twee Eucalyptus grandis x urophylla hibriede en Eucalyptus dunnii op drie groeiplekke, een eks-landbou en twee eks-bosbou, op die Zoeloeland kusvlakte en in die Natalse Middellande toegedien. Die ontwerp is nege keer in elke studiegebied herhaal. Oesreste is voor aanplanting op die Eucalyptus groeiplekke verbrand. Die voorkoms van Fusarium circinatum op die P. radiata groeiplek het onverwagte en hoogs uiteenlopende reaksies tot gevolg gehad. ’n Poging om die effek van die siekte te kwantifiseer, was slegs gedeeltelik suksesvol. Die gemiddelde BI van die kontrole behandeling, was 25. Die beste CV en CRF behandeling het onderskeidelik 42 % en 83 % hoër BI as die kontrole groep gehad, waarvan slegs die CRF behandeling beduidend was. Blaarontleding het gewys dat daar marginale of ontoereikende konsentrasies van P en Mg was. In Zoeloeland het die Eucalyptus hibriede ’n beduidende reaksie op N en P getoon met meer volume groei, LAI en N inhoud. Die toediening van 120 g N en 20 g P per boom op die eks-landbou groeiplek het ’n volume van 8 m3 ha-1 op eenjarige ouderdom tot gevolg gehad. Dis beduidend beter met 118 % en 80 % onderskeidelik vir die kontrole en beste CV behandeling. Die toediening van 80 g N en 20 g P per boom op die hervestigde eks-bosbou groeiplek, het ’n volume van 24.6 m3 ha-1 op eenjarige ouderdom tot gevolg gehad. Dit is 39 % beduidend en 7 % onbeduidend addisionele volume op eenjarige ouderdom vir onderskeidelik die kontrole groep en beste CV behandeling. ’n Onbeduidende depressie effek is met die alleen toediening van 20 g CV P gevind. In die Natalse Middellande groeiplek het die toediening van P ‘n vroeë reaksie in hoogte groei veroorsaak. Die toediening van 20 g CV P per boom, het ’n gemiddelde hoogte van 162.6 cm op die ouderdom van sewe maande tot gevolg gehad. Dit is 28 % beduidend hoër as die kontrole. Die toediening van 80 g CRF N en 20 g CV P per boom was onbeduidend. Toedienings van CRF N tot en met 120 g per boom het in die kusgebiede van Zoeloeland met ‘n lae organiese koolstof (OC) inhoud, groter groei as die aanbevole CV toedienings gehad. Die Middellande groeiplek met ’n hoër OC en klei inhoud, was die vroeë reaksie alleenlik beperk tot P bemesting.

Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-03T12:27:30Z No. of bitstreams: 1 2015_dis_lvsilva.pdf: 1231278 bytes, checksum: f2c7e3058523d6ccecefab2c7cf93932 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-03T12:27:44Z (GMT) No. of bitstreams: 1 2015_dis_lvsilva.pdf: 1231278 bytes, checksum: f2c7e3058523d6ccecefab2c7cf93932 (MD5) / Made available in DSpace on 2016-08-03T12:27:44Z (GMT). No. of bitstreams: 1 2015_dis_lvsilva.pdf: 1231278 bytes, checksum: f2c7e3058523d6ccecefab2c7cf93932 (MD5) Previous issue date: 2015 / SILVA, Leane Veras da. Componentes da biomassa e estrutura do capim-aruana sob duas frequências e duas intensidades de desfolhação. 2015. 56 f . : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Zootecnia, Fortaleza-CE, 2015 / This study evaluated the components of biomass and the canopy structure of aruana grass managed under two frequencies (FD, interception of the photosynthetically active radiation at 85 and 95% incident on the top of the canopy) and two intensities (ID, residual leaf area index of 1.0 and 1.8) of defoliation in a completely randomized design in a 2x2 factorial arrangement with five replications (paddocks). The experiment was conducted at the advanced field of Teaching and Study Center Forage, located in the municipality of Pentecoste, Ceará State. The times of entry and exit of animals were determined using the PAR/LAI Analyzer in Agriculture DECAGON PAR-80 for reading photosynthetically active radiation interception (PARI) and leaf area index (LAI). At the beginning and end of the rest period of each of the five experimental paddocks, the following structural characteristics were evaluated: sward height (cm); height of the first ligule, the oldest below the canopy; grazing horizon and tiller population density. The components of total forage biomass (TFB ha-1 cycle-1) were also quantified at the beginning and end of the rest period, from the collection using two frames of 0.25 m², and sent to the laboratory to separate the components: leaf, stem and dead material. After separation of the TFB components, samples were dried to constant weight in a forced ventilation oven at 55°C to constant weight to estimate the following parameters: total forage biomass (TFB kg ha-1 cycle-1), dead forage biomass (DFB kg ha-1 cycle-1), green forage biomass (GFB kg kg ha-1 cycle-1), green leaf biomass (GLB kg ha-1 cycle-1), green stem biomass (GSB kg ha-1 cycle-1), and green/dead material ratio (GM/DM) and leaf/stem ratio (L/S). The longest rest period was observed in pastures managed with lower rLAI and lower defoliation frequency (95% PARI), with average of 24 days. Biomass components and structural characteristics in the pre-grazing condition were affected (P <0.05) by FD, where the lower defoliation frequency resulted in higher production with considerable contribution of biomass of green stems and dead forage. The pre-grazing height showed a high correlation with the %PARI in the pre-grazing condition (r = 0.9285, P = 0.0001). Pastures managed with lower FD had low L/S, with average of 1.65, while those managed with higher FD, an average of 2.40. With increasing %PARI, we verified higher grazing horizons, with averages of 20.2 and 14.2 cm, for 95 and 85 %PARI, respectively. The components of the residual biomass were affected (P <0.05) by ID, with higher residual forage biomass observed for pastures managed with rLAI of 1.8. Pastures managed with 95x1.8 exhibited higher rGSB ¬and rDFB (P <0.05) compared to the other managements. Pastures managed with 95x1.0 showed an increase in TFB (P <0.05) over successive grazing cycles. Aruana grass supplied to sheep should be managed under 85% PARI frequency and defoliation intensity equal to 1.0 rLAI. / Avaliou-se os componentes da biomassa e a estrutura do dossel em capim-aruana sob duas frequências (FD - níveis de interceptação de 85 e 95% da radiação fotossinteticamente ativa incidente no topo do dossel) e duas intensidades (ID - índices de área foliar residual de 1,0 e 1,8) de desfolhação, em um delineamento inteiramente casualizado, num arranjo fatorial 2x2, com cinco repetições (piquetes). O experimento foi conduzido no campo avançado do Núcleo de Ensino e Estudos em Forragicultura, situado na Fazenda experimental Vale do Curú, localizada no município de Pentecoste-CE. Os momentos de entrada e saída dos animais foram determinados utilizando-se o Analisador PAR/LAI em Agricultura DECAGON PAR-80 para as leituras da interceptação de radiação fotossinteticamente ativa (IRFA) e do índice de área foliar (IAF). Foram avaliadas no início e no final do período de descanso de cada um dos cinco piquetes experimentais, as seguintes características estruturais: altura do pasto; altura da primeira lígula viva, a mais velha abaixo do dossel; horizonte de pastejo e densidade populacional de perfilhos. Os componentes da biomassa de forragem total (BFT) foram quantificados no início e final do período de descanso, a partir da colheita com duas molduras de 0,25 m², sendo encaminhadas ao laboratório para separação dos componentes: folha, colmo e material morto. Após a separação dos componentes da BFT, as amostras foram levadas à estufa de ventilação forçada à 55 °C até peso constante para estimativa das seguintes variáveis: biomassa de forragem total (BFT kg∙ha-1∙ciclo-1), de forragem morta (BFM kg∙ha-1∙ciclo-1 ), de forragem verde (BFV kg∙ha-1∙ciclo-1), de lâmina foliar verde (BLV kg∙ha-1∙ciclo-1), de colmo verde (BCV kg∙ha-1∙ciclo-1), além das relações material vivo/material morto (MV/MM) e folha/colmo (F/C). O maior tempo de descanso foi verificado para os pastos manejados com menor IAFr e menor frequência de desfolhação (95% de IRFA), com média de 24 dias. Os componentes da biomassa e as características estruturais na condição pré-pastejo foram afetados (P<0,05) pelas FDs, onde a menor frequência de desfolhação proporcionou maiores produções, com considerável contribuição de biomassa de colmos verdes e de forragem morta. A altura pré-pastejo apresentou boa correlação com a %IRFA na condição pré-pastejo (r=0,9285; P=0,0001). Pastos manejados com menor FD proporcionaram baixa F/C, com média de 1,65, enquanto pastos manejados com maior FD apresentaram média de 2,40. Com o aumento da %IRFA, foram verificados maiores horizontes de pastejo, com médias de 20,2 e 14,2 cm para as frequências de 95 e 85%IRFA, respectivamente. Os componentes da biomassa residual foram afetados (P<0,05) pelas IDs, com maior biomassa de forragem residual observada para os pastos manejados com IAFr de 1,8. Os pastos manejados com 95x1,8 apresentaram BCVr e BFMr superiores (P<0,05) aos demais manejos. Pastos manejados com 95x1,0 apresentaram incremento (P<0,05) de BFT ao longo de ciclos sucessivos de pastejo. O capim-aruana, para utilização com ovinos, deve ser manejado com frequência de 85% de IRFA e intensidade de desfolhação equivalente a IAFr de 1,0.

Made available in DSpace on 2016-12-23T13:51:52Z (GMT). No. of bitstreams: 1 Valeria Hollunder Klippel.pdf: 1679011 bytes, checksum: 81fc92fdc0af96774ee580cab6eba66b (MD5) Previous issue date: 2011-07-25 / This study aimed to evaluate different forest restoration methods of a Tableland Forest, by manipulating the floristic composition and silvicultural practices. With this foundation, it was installed in August of 2007, at the Reserva Natural Vale (RNV) in Linhares - ES, an experiment in randomized blocks with 4 treatments and 3 replications (a total of 12 plots): T1 (Control): Only leafcutter ants control; T2: Selective manual mowing, selective chemical weeding, control of ants and species tolerant to the herbicide; T3: Same as treatment 2, but with the planting of Atlantic Forest pioneer species in the spacing of 5 x 5 m, interspersed, in the same spacing, the seeding of Sesbania grandiflora in pits (10 seeds per pit); T4: Same as treatment 2, but with the planting of 54 Atlantic Forest species in the spacing close to 3 x 3 m. From the moment of installation (2007) until the third year of the study (2010) annual inventories were performed in all plots, to study the arboreal vegetation flora and growth. Moreover, at the third year after the experiment implementation, soil samples were also collected at four depths (0-5, 5-10, 10-20 and 20-40 cm) for later chemical analysis; accumulated litter, for studying biomass and nutrient content and level, and leaf area index (LAI). Regarding the soil chemical attributes, only statistic differences were found for the studied treatments in depths of 0-5 cm, where the highest values of Ca, sum of bases and CEC were observed for the treatment 4 and greater Na Saturation Index value to the treatment 1, and 10-20 cm, where the treatment 4 showed higher Ca value. There were no statistical differences in the accumulated litter biomass. The lower C/N was obtained by the treatment 3. This treatment also had the highest leaf area index. The elimination of weed competition acted positively on trees growth. The entrance of individuals and basal area was higher for treatments 3 and 4 / Esse estudo teve como objetivo avaliar diferentes métodos de restauração florestal de uma Floresta de Tabuleiro, pela manipulação da composição florística e práticas silviculturais. Com esta fundamentação foi instalado em agosto do ano de 2007, na Reserva Natural Vale (RNV) em Linhares ES, um experimento em blocos casualizados, com 4 tratamentos e 3 repetições (totalizando 12 parcelas): T1 (Controle): Somente o controle de formigas cortadeiras; T2: Roçada manual seletiva, capina química seletiva, controle de formigas e as espécies tolerantes ao herbicida; T3: Idêntico ao tratamento 2, mas com o plantio de espécies pioneiras da Mata Atlântica no espaçamento de 5 x 5 m, intercalado, no mesmo espaçamento, o semeio de Sesbania grandiflora em covas (10 sementes por cova); T4: Idêntico ao tratamento 2, mas com o plantio de 54 espécies da Mata Atlântica no espaçamento próximo de 3 x 3 m. Desde o momento de instalação (2007) até o terceiro ano de estudo (2010) foram realizados inventários anuais em todas a as parcelas, para estudo da florística e crescimento da vegetação arbórea. Além disso, no terceiro ano após a implantação do experimento, também foram coletadas amostras de solo em quatro profundidades (0 5; 5 10; 10 20 e 20 40 cm) para posterior análise química; serapilheira acumulada, para estudo da biomassa e do teor e conteúdo de nutrientes; e índice de área foliar (IAF). Em relação aos atributos químicos do solo, somente foram encontradas diferenças estatísticas para os tratamentos estudados nas profundidades de 0-5 cm, onde os maiores valores de Ca, soma de bases e CTC foram observados para o tratamento 4 e maior valor do ISNa para o tratamento 1, e de 10-20 cm, onde o tratamento 4 apresentou maior valor de Ca. Não foram observadas diferenças estatísticas para a biomassa da serapilheira acumulada. A menor C/N foi obtida pelo tratamento 3. Esse tratamento também apresentou o maior índice de área foliar. A eliminação da matocompetição atuou positivamente no crescimento da vegetação arbórea. O ingresso de número de indivíduos e de área basal foi superior para os tratamentos 3 e 4.

Made available in DSpace on 2016-06-02T19:31:38Z (GMT). No. of bitstreams: 1 1456.pdf: 806888 bytes, checksum: c1a017c0d739e9db5205b7784a9e4a47 (MD5) Previous issue date: 2007-06-06 / Universidade Federal de Sao Carlos / Young plants of Coffea arabica grafted over C. canephora were submitted to six watering cycles (WC) during 35 days. Each WC was accomplished until net photosynthesis (PN) close to zero or leaf water potential (&#936;) close to -2.0 MPa in Acauã (AC), Mundo- Novo (MN), and Obatã (OB) cultivars. After 2 WC (about 10 days) gs dropped from 0.15 to 0.01 mol m-2 s-1 in all cultivars changing the pattern of leaf gas exchange in subsequent WC. From 3 to 6 WC the cultivars showed high oscillations of water use efficiency or substomatal CO2 concentration (Ci) besides negative PN at the end of WC. After 3 WC, gs increased faster than PN after watering and Ci increased indicating some damage in photosynthetic machinery. It happened strongly in OB, which showed progressive reduction of PN after 3 WC and the lowest values of &#936; (-2.0 MPa) at the end of 6 WC. The survivorships for cultivars were 80% till 3 WC and 70% after 6 WC. The gas exchange pattern alteration could indicate the potential hardening of AC, MN and OB cultivars. After field plantation of hardened and control (without perivous hardening) Mundo-Novo and Obatã cultivars, with 180-days-old, it was observed significant (p<0.05) greater accumulation of leaf, stem and root biomass in hardened in control plants. Stem diameter, height and the number of leaf and branch were also higher (p<0.05) in previous hardened individuals. Greater differences in crown structure and biomass between control and hardened plants were observed mainly after the first period of low water availability (210 days under field conditions). The higher leaf number and leaf area in more branched crowns could carbon assimilation and grain production. For practical proposes, 3 WC before growing under field conditions are sufficient for changing consistently the leaf gas exchange pattern in 3 cultivars studied, keeping photosynthetic machinery free of damage and high survivorship. Previous hardening proportioned less interrupted vegetative development after transplantation under field conditions in both cultivars. / Plantas jovens de Coffea arabica enxertadas sobre C. canephora foram submetidas a 6 ciclos de suspensão de rega (CR) durante 35 dias. Cada CR foi acompanhado até que a fotossíntese líquida (PN) fosse próxima de zero ou até que o potencial hídrico foliar (&#936;) fosse próximo de -2.0 MPa nos cultivares Acauã (AC), Mundo-Novo (MN) e Obatã (OB). Após 2 CR (cerca de 10 dias) os valores médios de condutância estomática (gs) diminuíram de 0,15 para 0,01 mol m-2 s-1 em todos os cultivares, mudando o padrão de trocas gasosas nos subseqüentes CR. De 3 a 6 CR os cultivares apresentaram maiores oscilações da eficiência do uso da água e da concentração substomática de CO2, além de valores negativos de PN ao final dos CR. Após 3 CR ocorreu um aumento proporcionalmente maior em gs do que em PN após rega, com um aumento correspondente de Ci, indicando possíveis danos no aparato fotossintético. Este evento ocorreu de forma mais clara em OB, o qual demonstrou redução progressiva de PN após 3 CR e os menores valores de &#936; (-2,0 MPa) ao final de 6 CR. A sobrevivência dos cultivares foi de 80% em 3 CR e 70% em 6 CR. As alterações dos padrões de trocas gasosas nos cultivares AC, MN e OB podem indicar que os exemplares foram potencialmente rustificados. Após o plantio de MN e OB rustificados e controle (sem prévia rustificação) em campo, com 180 dias de idade, foi observado no tratamento rustificado valores significativamente (p<0,05) maiores do acúmulo de biomassa e do número de componentes estruturais da copa. A rustificação prévia proporcionou maior acumulo de biomassa de folhas, de caule e de raízes que nas plantas controle em ambos os cultivares. O diâmetro do caule, a altura, o número de folhas e o número de ramos também foram significativamente maiores (p<0,05) nos indivíduos previamente rustificados. As maiores diferenças da estrutura da copa e da biomassa acumulada entre plantas controle e rustificadas foram encontradas principalmente após o primeiro período de rezudida disponibilidade hídrica (210 dias em condições de campo). O maior número de folhas e a maior área foliar em copas mais ramificadas podem proporcionar um aumento da assimilação de carbono por planta e maior produção de grãos nas plantas rustificadas. Em termos práticos, 3 CR antes do crescimento em campo são suficientes para mudar consistentemente o padrão de trocas gasosas foliares nos 3 cultivares estudados, mantendo o aparato fotossintético livre de danos e proporcionando maior sobrevivência. A prática de rustificação prévia antes do plantio deve ser adotada nos cultivares estudados, pois o custo é reduzido e o desenvolvimento vegetativo inicial é fortemente favorecido após o transplante sob condições de campo.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Avaliou-se as trocas gasosas, o fluxo de biomassa e as caracterÃsticas estruturais do capim-aruana pastejado sob lotaÃÃo rotativa por ovinos Morada Nova submetidos a quatro nÃveis de suplementaÃÃo concentrada (0,0; 0,6; 1,2 e 1,8% do PC), com perÃodo de ocupaÃÃo de quatro dias e descanso quando da interceptaÃÃo de 90% da radiaÃÃo fotossinteticamente ativa (IRFA), num delineamento inteiramente casualizado, num arranjo em parcelas subdivididas, sendo os nÃveis de suplementaÃÃo as parcelas e os ciclos de pastejo as subparcelas. A condiÃÃo de pÃs-pastejo consistiu em um Ãndice de Ãrea foliar de 1,0. Constatou-se efeito linear crescente para a taxa de alongamento das hastes e taxa de aparecimento foliar em funÃÃo dos nÃveis de suplementaÃÃo. As taxas de produÃÃo e acÃmulo de forragem foram incrementadas pelos nÃveis de suplementaÃÃo. As variÃveis das trocas gasosas das folhas recÃm-expandidas: transpiraÃÃo, condutÃncia estomÃtica, taxa de fotossÃntese foliar, mostraram efeito somente de ciclo de pastejo. NÃo houve nenhum efeito significativo sobre as variÃveis das trocas gasosas das folhas emergentes. Os componentes da biomassa pÃs-pastejo registraram efeito significativo da interaÃÃo nÃveis de suplementaÃÃo e ciclos de pastejo para biomassa de forragem verde residual (BFVr), lÃmina foliar verde residual (BLVr), colmo verde residual (BCVr) e relaÃÃo folha:colmo (F_Cr) residual, estas variÃveis, com exceÃÃo da F_Cr apresentaram efeito quadrÃtico nos ciclos dois e trÃs, confirmando o efeito substitutivo, a partir do nÃvel de suplementaÃÃo de 0,86%, com o mÃnimo estimado de 257,53 Kgâha-Ââano-1, para a BLVr. A relaÃÃo material vivo_ material morto residual apresentou efeito linear crescente em funÃÃo dos nÃveis de suplementaÃÃo. A altura do pasto e a densidade populacional de perfilhos residual foram afetadas somente pelos ciclos de pastejo. A biomassa de forragem verde (BFV) e de lÃmina foliar verde (BLV) apresentaram efeito da interaÃÃo nÃveis de suplementaÃÃo e ciclos de pastejo. A BLV registrou efeito quadrÃtico para os ciclos dois e trÃs, onde os maiores valores foram de 1489,47, no nÃvel de 0,62, do segundo ciclo e de 1554,95 Kgâha-Ââano-1no ciclo trÃs com nÃvel de suplementaÃÃo de 0,14 %. As trocas gasosas nÃo sÃo afetadas pelos nÃveis de suplementaÃÃo. As caracterÃsticas morfogÃnicas do pasto de capim-aruana sÃo afetadas linearmente pelos nÃveis crescentes de suplementaÃÃo. Os componentes estruturais do pasto de capim-aruana sÃo afetados pelos nÃveis crescentes de suplementaÃÃo concentrada, registrando efeito substitutivo do suplemento. / This study evaluated the gas exchange, the biomass flow and the structural characteristics of Panicum maximum cv. Aruana grazed by Morada Nova sheep under rotational stocking and supplied with four concentrate supplementation levels (0.0; 0.6; 1.2 and 1.8% body weight), using four day-grazing periods and rest when the interception of 90% of the photosynthetic active radiation (PAR). The experiment was a completely randomized split-plot design with supplementation levels as plots and grazing cycles as subplots. The post-grazing condition consisted of a leaf area index of 1.0. We observed an increasing linear effect for stem elongation rate and leaf appearance rate according to the supplementation levels. The production and accumulation rates of forage also increased according to the supplementation levels. The different grazing cycles affected the variables of gas exchange of the recently expanded leaves, namely transpiration, stomatal conductance, leaf photosynthesis rate. In turn, no significant effect was detected for the gas exchange variables of emergent leaves. Biomass components during the post-grazing period showed a significant effect of the interaction between supplementation levels and grazing cycles for residual green forage biomass (BFVr), residual green leaf biomass (BLVr), residual green stem biomass (BCVr) and residual leaf:stem ratio (F_Cr). All these variables, with the exception of F_Cr, presented a quadratic effect in the cycles two and three, confirming the substitutive effect from the supplementation level of 0.86%, with the minimum estimated at 257.53 Kgâha-Ââyear-1, for BLVr. The ratio between living and senescent material showed an increasing linear response as a function of the supplementation levels. The pasture height and the residual tiller population density were affected only by grazing cycles. Green forage biomass (BFV) and green leaf biomass (BLV) presented a quadratic effect of the supplementation levels and grazing cycles. BLV showed a quadratic effect for the cycles two and three, where the higher values were 1489.47, at the level of 0.62, in the second cycle, and 1554.95 Kgâha-Ââyear-1 in the third cycle with a supplementation level of 0.14%. Gas exchange was not influenced by the supplementation levels. Morphogenetic traits of the aruana grass pasture are linearly affected by increasing levels of supplementation. The structural components of the aruana grass pasture are influenced by the increasing levels of concentrate supplementation, with a substitutive effect of the supplement.

Submitted by (edna.saturno@ufrpe.br) on 2017-03-23T12:40:14Z No. of bitstreams: 1 Bruno Leal Viana.pdf: 1623265 bytes, checksum: 5707cff554bc2506977fb551f2f6b45e (MD5) / Made available in DSpace on 2017-03-23T12:40:14Z (GMT). No. of bitstreams: 1 Bruno Leal Viana.pdf: 1623265 bytes, checksum: 5707cff554bc2506977fb551f2f6b45e (MD5) Previous issue date: 2009-07-27 / The research was conducted at the Experimental Station of the Agronomic Institute of Pernambuco (IPA) located in Itambé, dry rainforest region of Pernambuco. The objective was to estimate the coefficients of repeatability, of determination (R2) and the number of measures needed to predict the real value [using principal component analysis (PCA)] to variable morphophysiological and productive, and the responses dwarf elephant grass pasture under grazing sheep. The experiment was carried out in a randomized block design with five Pennisetum purpureum clones were evaluated: Taiwan A-146 2.27, Taiwan A-146 2.37, Taiwan A-146 2114, Merker Mexico MX 6.31 and Mott. Evaluations were performed during five grazing cycles, from September 2008 to April 2009. Twenty five sheep (42 kg average liveweight) were used in a mobgrazing protocol, leaving the paddock at 30 cm of residual stubble height. The clones were managed under rotational stocking, with 32 days of resting period and three days of grazing period for cycles 1, 2, and 5, and 64 days of resting period and two days ofgrazing period for cycles 3 and 4. Response variables analyzed at pre- and post-grazing included leaf area index, light interception, leaf angle, average sward height, green portion of herbage mass (DM basis). In addition, we estimated net herbage accumulation (ALF), in kg DM ha-1 cycle-1, and net herbage accumulation rate (TALF), in kg DM ha-1 day-1. Data were analyzed by univariate or multivariate analysis of repeated measures over time in the SAS. Means were compared by Tukey test at 5% probability. According to the PCA, for the variables LAI and LI in cycles of shorter period of regrowth, and height of plants in the cycles of higher period of rest is needed only one measurement (R2=0.80), classifying them among the characteristics evaluatedas the easiest prediction in elephant grass clones. Assessments for NHA and NHAR size of dwarf elephant grass, under grazing, need long experimental periods. / Esta pesquisa foi realizada na Estação Experimental do Instituto Agronômico de Pernambuco (IPA), no município de Itambé, Zona da Mata Seca de Pernambuco, com o objetivo de estimar os coeficientes de repetibilidade, de determinação (R2) e o número mínimo de medições necessárias para predizer o valor real [pela análise dos componentes principais (ACP)] para variáveis morfofisiológicas e produtivas, bem como as respostas dos pastos de capim elefante de porte baixo sob o pastejo de ovinos. O experimento foi conduzido no delineamento em blocos casualizados, com cinco clones de Pennisetum purpureum (Taiwan A-146 2.27, Taiwan A-146 2.37, Taiwan-146 2.114, Merker México MX 6.31, e Mott). As avaliações foram realizadas em cinco ciclos de pastejo, compreendidos entre os meses de setembro de 2008 a abril de 2009. Foram utilizados 25 ovinos, com peso médio de 42 kg, como animais pastejadores em “mobgrazing”, buscando-se a altura de 30 cm de resíduo pós-pastejo. Os clones foram manejados sob lotação intermitente, sendo 32 dias de descanso e três de pastejo para os ciclos 1, 2 e 5 e 64 dias de descanso e dois de pastejo para os ciclos 3 e 4. As variáveisanalisadas foram índice de área foliar, interceptação luminosa, ângulos foliares médios realizados, alturas médias do dossel e massa de forragem seca verde (MSV), no pré e pós pastejo. Foram estimados ainda o acúmulo líquido de forragem (ALF), em kg MS ha-1 ciclo-1 e a taxa de acúmulo líquido de forragem (TALF), em kg MS ha-1 dia-1. Os dados foram analisados por meio de análise univariada ou multivariada de medidas repetidas no tempo no SAS. Para comparação das médias foi utilizado o teste de Tukey a 5% de probabilidade. De acordo com a ACP, para as variáveis IAF e IL nos ciclos de menor período de rebrota, e altura média de plantas nos ciclos de maior período de descanso é necessário apenas uma medição (R2=0,80), classificando-as entre às características avaliadas como as de mais fácil predição em clones de capim elefante. Avaliações de ALF e de TALF para capim elefante de porte baixo, sob pastejo, necessitam de períodos experimentais mais longos.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Plant functional types defined from morphological attributes are fundamental to understanding functioning of grasslands communities. Thus, to build a classification based solely on grasses (family of greater biomass contribution), it is necessary for increasing the knowledge about complex ecosystems. This work aims to characterize vegetation dynamics by species and by functional types of grasses of two RS physiographic regions (Depressão Central-Santa Maria and Campanha-Bagé) under different managements. The evaluated treatments were: natural pasture and natural pasture overseeded with cool season species (Bagé) and natural pasture submitted to burning and grazing treatments (Santa Maria). For this, permanent transects were used in order to represent the different communities at paddock level. Vegetation dynamics was evaluated using procedures of BOTANAL method. Tillers of grasses with contributions exceeding 3% of total aboveground biomass were collected for subsequent measurement of the attributes specific leaf area (AFE) and leaves dry matter content (TMS). Burned treatments presented greater contribution of Andropogon lateralis, while in grazed treatments there was a greater species diversity. Introduction of cool season species combined with fertilizer promotes an increase of species characterized by resources´ capture. TMS was more stable for species linked to capturing resources strategy and AFE was more robust for species characterized by resources conservation. Therefore, until a regional data basis were developed, it is recommended to use both attributes for future research. / Tipos funcionais de plantas definidos a partir de atributos morfológicos são fundamentais para o entendimento do funcionamento de comunidades campestres. Desta maneira, a construção de uma tipologia baseada apenas em gramíneas (família de maior contribuição), torna-se necessária para o avanço do conhecimento sobre ecossistemas complexos. Este trabalho tem por objetivo caracterizar duas regiões fisiográficas do RS (Depressão Central-Santa Maria e Campanha-Bagé) sob distintos manejos quanto à dinâmica vegetacional por espécies e por tipos funcionais de gramíneas. Os tratamentos avaliados foram: pastagem natural e pastagem natural com introdução de espécies hibernais (Bagé) e pastagem natural submetida a tratamentos de queima e pastejo (Santa Maria). Para isto, foram dispostas transectas fixas de modo a representar as diferentes comunidades em nível de potreiro. Foi avaliada a dinâmica vegetacional utilizando os procedimentos do método BOTANAL. Foram coletados afilhos das gramíneas com contribuição superior a 3% da biomassa aérea total para posterior medida dos atributos área foliar específica (AFE) e teor de matéria seca da folha (TMS). Os tratamentos queimados tiveram maior contribuição de Andropogon lateralis, enquanto nos tratamentos pastejados houve uma maior diversidade de espécies. A introdução de espécies de estação fria, aliada à adubação, promove um acréscimo das espécies caracterizadas por captura de recursos. O TMS se mostrou mais estável para espécies ligadas à estratégia de captura de recursos e a AFE mais robusta para as espécies caracterizadas pela conservação de recursos. Por tanto, até que se desenvolva uma base regional de dados, recomenda-se que futuras pesquisas continuem a utilizar os dois atributos.

Le suivi des variables biophysiques à l’échelle globale sur de longues périodes de temps est essentiellepour répondre aux nouveaux enjeux que constituent le changement climatique et la sécurité alimentaire. L’indice foliaire (LAI) est une variable de structure définissant la surface d’interception du rayonnement incident et d’échanges gazeux avec l’atmosphère. Le LAI est donc une variable importante des modèles d’écosystèmes et a d’ailleurs été reconnue comme variable climatique essentielle (ECV). Cette thèse a pour objectif de fournir des estimations globales et continues de LAI à partir d’observations satellitaires en temps quasi-réel en réponse aux besoins des utilisateurs pour fournir des diagnostiques et pronostiques de l’état et du fonctionnement de la végétation. Quelques produits LAI sont déjà disponibles mais montrent des désaccords et des limitations en termes de cohérence et de continuité. Cette thèse a pour objectif de lever ces limitations. Dans un premier temps, on essaiera de mieux définir la nature des estimations de LAI à partir d’observations satellitaires. Puis, différentes méthodes de lissage te bouchage des séries temporelles ont été analysées pour réduire le bruit et les discontinuités principalement liées à la couverture nuageuse. Finalement quelques méthodes d’estimation temps quasi réel ont été évaluées en considérant le niveau de bruit et les données manquantes.Les résultats obtenus dans la première partie de cette thèse montrent que la LAI effectif et bien mieux estimé que la valeur réelle de LAI du fait de l’agrégation des feuilles observée au niveau du couvert. L’utilisation d’observations multidirectionnelles n’améliore que marginalement les performances d’estimation. L’étude montre également que les performances d’estimation optimales sont obtenues quand les solutions sont recherchées à l’intérieur d’une enveloppe définie par l’incertitude associée aux mesures radiométriques. Dans la deuxième partie consacrée à l’amélioration de la continuité et la cohérence des séries temporelles, les méthodes basées sur une fenêtre temporelle locale mais de largeur dépendant du nombre d’observations présentes, et utilisant la climatologie comme information a priori s’avèrent les plus intéressantes autorisant également l’estimation en temps quasi réel. / Monitoring biophysical variables at a global scale over long time periods is vital to address the climatechange and food security challenges. Leaf Area Index (LAI) is a structure variable giving a measure of the canopysurface for radiation interception and canopy-atmosphere interactions. LAI is an important variable in manyecosystem models and it has been recognized as an Essential Climate Variable. This thesis aims to provide globaland continuous estimates of LAI from satellite observations in near-real time according to user requirements to beused for diagnostic and prognostic evaluations of vegetation state and functioning. There are already someavailable LAI products which show however some important discrepancies in terms of magnitude and somelimitations in terms of continuity and consistency. This thesis addresses these important issues. First, the nature ofthe LAI estimated from these satellite observations was investigated to address the existing differences in thedefinition of products. Then, different temporal smoothing and gap filling methods were analyzed to reduce noiseand discontinuities in the time series mainly due to cloud cover. Finally, different methods for near real timeestimation of LAI were evaluated. Such comparison assessment as a function of the level of noise and gaps werelacking for LAI.Results achieved within the first part of the thesis show that the effective LAI is more accurately retrievedfrom satellite data than the actual LAI due to leaf clumping in the canopies. Further, the study has demonstratedthat multi-view observations provide only marginal improvements on LAI retrieval. The study also found that foroptimal retrievals the size of the uncertainty envelope over a set of possible solutions to be approximately equal tothat in the reflectance measurements. The results achieved in the second part of the thesis found the method withlocally adaptive temporal window, depending on amount of available observations and Climatology as backgroundestimation to be more robust to noise and missing data for smoothing, gap-filling and near real time estimationswith satellite time series.