Field experiments were conducted on an Alfisol in the semi-arid tropics of northern Australia to investigate nitrogen (N) cycling in the leucaena (Leucaena leucocephala) alley cropping system. This is a farming system in which maize (Zea mays L.) is grown in alleys formed by leucaena hedgerows spaced 4.5 metres apart. Mineralization of N from Ieucaena (prunings) and maize residues was studied under field conditions. Response of maize growth to addition of N fertilizer and plant residues was evaluated both in field plot and microplot experiments. The fate of fertilizer N and leucaena N was examined over four consecutive seasons. The decomposition (loss of mass) of dry, cut 15N-labelled leucaena residues differed from that of intact fresh leucaena prunings in the first cropping season although no difference was detected after one year. At the end of one cropping season, 3 months after application, 58-72% of 15N-labelled leucaena had decomposed compared to only 34-36% of fresh leucaena prunings. Similar trends occurred at 20 and 52 days after application. The extent of decomposition of fresh leucaena prunings (28-33%) was similar at two loading rates (2.4 and 4.7 t DM ha -1) by 3 months after addition. About 72% of young 15N labelled maize residues was decomposed by 3 months after addition in the presence of fresh leucaena prunings. Decomposition of 15N-labelled leucaena residues and unlabelled fresh prunings was 91% and 88% respectively 14 months after addition. After 2 years the corresponding values were 96% and 94%. When N content of the recovered residues was taken into account, the values were 95% and 94% after 14 months, and the same (97%) after 2 years. Maize yield and N uptake were significantly increased following addition of either unlabelled fresh leucaena residues or 15N-labelled thy Ieucaena residues. Application of N ferilizer produced a thither increase in the presence of the residues. The maize yield and N uptake with the 15N-labelled leucaena were not different from those with the unlabelled residues. There was a significant positive interaction between N fertilizer and leucaena prunings which increased maize production. Addition of maize residues decreased the yield and N uptake of maize compared with that obtained in the presence of N fertilizer at 40 kg N ha~1 and leucaena residues (2.4 t DM ha-1). There was a marked residual benefit of N fertilizer applied in the first season at 36 kgN hat in the presence of leucaena prunings on the second maize crop yield and N uptake, but not on the third crop. However, a significant residual benefit of leucaena prunings added in the first season was found in DM yield and N uptake of the second and third maize crop. The short-term fate of 15N applied in plant residues was examined during two separate cropping seasons. By 20 days after application of separate 15N-labelled leucaena leaves, stems and petioles, 3-9% of the added 15N could be found in maize plants, 33-49% was in surface residues, 36-48% in the 2 m soil proffle and 0.3-22% unaccounted for. In a separate experiment when leucaena components were not separated, 5% of 15N applied in leucaena residues was taken up by maize 52 days after addition, 45% was in residues, 25% was in soil and 25% was unaccounted for. Jn another experiment, maize recovered 6% of added leucaena 15N after 2 months, 39% remained in residues, 28% was in soil and 27% was not recovered. Incorporation of 15N-labelled leucaena residues in the soil did not increase recoveiy of leucaena 15N by maize compared with placement of the residues on the soil surface. By the end of one cropping season (3 months after application), 9% of added 15N was recovered by maize from 15N-labelled leucaena. There was a similar 15N recoveiy from 15N-labelled maize residues applied as mulch at 1.7 t DM ha1 together with unlabelled leucaena prunings at 2.4 t DM ha ~. In both cases, 30-32% of added 15N was detected in soil, 28% in residues, and 31-34% apparently lost. The short-term fate of fertilizer 15N was different from that of 15N added in plant residues. In a 52-day experiment, maize recovered 65-79% of fertilizer 15N applied at low rates (6.1 and 12.2 kg N ha -1) in the presence of leucaena prunings, 21-34% was present in soil, and less than 1% was not recovered. By 2 months after application, recoveiy of fertilizer 15N by maize was 41% from N fertilizer added at 80 kg N ha -1, 35% from N fertilizer at 40 kg N ha -1 in the presence of leucaena prunings, and 24% from N fertilizer at 40 kg N ha -1 in the presence of maize residues and leucaena prunings. The corresponding deficits (unaccounted-for 15N) were 37%, 38% and 47% respectively. A small but significant amount of the fertilizer 15N was present in the unlabelled leucaena residues (3%) and in the mixture of unlabelled leucaena and maize residues (7%) present on the soil surface. However, application of the plant residues did not affect recoveiy of the fertilizer 15N in soil (21-24%). When N fertilizer was applied at 40 kg N hi1 in the presence of leucaena prunings, 43% of fertilizer 15N was recovered by maize at the end of cropping season, 20% in soil, 2% in residues, and 35% unaccounted for. The long-term fate of fertilizer 15N was compared with that of leucaena 15N in an experiment over four cropping seasons. In the first season, maize tops recovered 50% of the fertilizer 15N but only 4% of the leucaena 15N. In the second, third and fourth seasons, maize (tops + roots) recovered 0.7%, 0.4% and 0.3% of the initial fertilizer 15N compared with 2.6%, 1.8% and 1.4% of the initial leucaena 15N. In the second, third and fourth seasons, recovery of the initial fertilizer 15N (12-14%) in soil was much lower than that of the initial leucaena 15N (38-40%). There was no further loss of the fertilizer 15N after the first season. However, the cumulative 15N deficit for the leucaena 1N in the first two seasons was 50%--thissuggested an additional loss of 23% since the end of the first season. There was no further loss of 15N from either residual fertilizer 15N or residual leucaena 15N in the third and fourth seasons. In conclusion, application of leucaena prunings could substantially increase maize yield and N uptake although some supplementary N fertilizer may be required to achieve maximum crop yield. Maize recovered only a small amount of added leucaena N in the first year. Most of the leucaena residue N was present in the soil and remaining residues after one season. This residue N would be gradually available for plant uptake by subsequent crops. Of course, annual additions of leucaena prunings would appreciably increase the pool of available N over time. Thus, application of leucaena prunings could substantially improve soil fertility in the long term.

Two methods of estimating the intake of a 25% leucaena : 75% grass hay diet by young male Boer goats were assessed, (a) The purine derivative technique which uses the urinary excretion of purine derivatives (expressed relative to creatinine concentration in the same sample) as an index of feed intake, and (b) the conventional marker method, utilizing chromic oxide (Cr₂O₃) contained in gelatin capsules and dosed twice daily, as the marker. Following a prerun the two techniques were compared in three runs of an indoor experiment. In each run 10 goats were randomly allocated to five feeding levels (500 to 1100 g fodder d ¯¹ on air dried basis). A preliminary and an adaptation period during which goats were dosed with the Cr₂O₃ and fed their daily feed allowance, was followed by a 4 day collection period during which spot samples of urine were collected and analysed for allantoin and creatinine (allantoin being used instead of total PDs) and faecal samples were collected for chromium analysis and percentage dry matter determination. For the first two runs, two grab samples per day for each goat were bulked and analysed for chromium content. For the last run, the total daily faecal collection was subsampled and analysed for chromium. Work was done in metabolic crates to determine the effect of time of collection on the ratio of allantoin : creatinine (A/C) in spot urine samples and it was found to non-significant (P>0.05). Linear regressions of: (a) feed intake expressed per unit metabolic mass (g.d ¯¹.LW ¯°∙⁷⁵ (I_mmass)) against A/C ratio; (b) faecal output (g d ¯¹) against feed intake (g d ¯¹); and (c) faecal chromium concentration (mg kg ¯¹) against faecal output (g d ¯¹) were fitted to the data. During the prerun, only regression (a) was fitted and was non-significant (P>0.05), showing no trend at all. For the first true run, the regression of I_mmass against A/C ratio was significant and the correlation was high (P≤ 0.001, R² [A] 0.715, n = 10) but for the second and third runs, the correlations only became significant when the apparent outliers were discarded from the data. (Run 2: P≤ 0.001, R² [A] 0.824, n = 8; Run 3: P≤ 0.05, R² [A] 0.430, n = 9). It was concluded that the relation between I_mmass and A/C ratio is not well enough defined to be used for predictive purposes. When regression (b) was investigated, all the runs produced significant results (P≤0.001, P≤0.01, P≤ 0.001 for runs 1,2 and 3 respectively) however the correlations were not as high as expected (R² [A] being 0.714, 0.565 and 0.863 respectively). For the regression of faecal Cr concentration against faecal output (regression c), all runs showed significant relations (P< 0.001, P< 0.0001, P:s 0.001 for runs 1,2 and 3 respectively) and the correlations were high (R²[A] being 0.836, 0.837 and 0.912 respectively). The data from the three runs were pooled and single equations established for regressions (b) and (c) to allow for the prediction of intake from faecal chromium concentration. Faecal output = feed intake * 0.448 + 19.341 (P≤ 0.001, r 0.853, R² [A] 0.718, SE 25.664, n - 30) Faecal chromium concentration = faecal output * -241.547 + 1.315E+05 (Ps 0.001, r 0.904, R² [A] 0.811, SE 5603.788, n = 30). In vitro figures were determined for a range of leucaena : hay mixes but no apparent trend was found between percentage leucaena in the mix and the digestibility of the mix. These results compared favourably with in vivo results obtained for a 25% leucaena : 75% hay mix. Neither technique proved entirely satisfactory, but the external marker method was found to be more effective than the purine derivative technique. More work is required especially with respect to the latter method. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.

Thesis (Ph. D.)--Oregon State University, 1997. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Comportamento meiótico e fertilidade do pólen foram estudados em um total de 49 acessos de 14 taxa do gênero Leucaena, leguminosas arbóreas fixadoras de nitrogênio nativas da América Centrai. As dipióides L. macrophytia, L. pulverulenta, L. retusa, L. salvadorensis, L. shannonii e L. trichandra apresentaram pareamento cromossõmico regular, preferencialmente em bivalentes, mas quadrivaientes e outras anormalidades foram observados em freqüências variadas. Nas tetrapióides L. confertiflora, L. diversifoiia, L. invoiucrata, L. feucocephaia, L. paiiida e no híbrido L. x spontanea a associação cromossomica mais comum também foram bivalentes, mas quadrivalentes e outras anormalidades foram observadas em freqüências variadas. O acesso L. ? hybrid apresentou predominantemente várias irregularidades, como univaientes, muitivalentes e aderências cromossõmicas. Nas espécies dipióides a ocorrência de quadrivalentes pode apoiar sua origem paleopoliplóide. A presença de quadrivalentes nas espécies polipioides apóia urna origem aiotetrapióide "segmentar', mas a autopoiipioidia com subseqüente diploidização não pode ser totalmente descartada. O índice meiótico foi superior a 80% na maioria dos acessos, refletindo a regularidade meiótica. A fertilidade do pólen variou de 71 a 98%, com algumas exceções. A presença de até 19% de díades e tríades e de macropóiens em espécies dipióides e tetrapioides (até de 7% em L. trichandra) demonstram que gametas não reduzidos não são raros em Leucaena. Estes resultados apresentam peia primeira vez uma análise meiótica detalhada e abrangente para Leucaena e demonstram como a citogenética clássica pode fornecer dados importantes para estudos taxonõmicos, evolutivos e no melhoramento de plantas. / Meiotic behavior and poiien tertffity were studied in a total of 49 accessions of 14 taxa of the Central American nitrogen fixing muitipurpose tree genus Leucaena. The dipioid L. macrophylla, L. pulverulenta, L. recusa, L. saivadorensis, L. shannonii and L. trichandra presented regular chromosome pairing, mostiy in bivalents, but quadrivaients and other abnormaiities were observed in varying frequencies. In tetrapioid L. confertitiora, L. diversifolia, L. involucraã, L ieucocephaia, L. pallida and the hybrid L. x spontanea bivalents were also the most common chromosome associations, but quadrivaients and others abnormaiities were observed in varying frequencies. The L. ? hybrid accession presented a predominance of severa! irreguiarities, such as univalents, muitivalents and chromosome stickiness. In dipioid species the commom occurrence of quadrivalents couid support their paleopoiypioid origin. The presence of quadrivaients in poiypioid species supports a segmentai aiiotetrapioid origin, but autopolypioidy with subsequent diplodization cannot be ruled out. Meiotic indexes were mostiy over 80% refiecting the rather regular meiotic behavior. Poilen fertility ranged from 71 to 98%, with some exceptions. The presence of up to 19% dyads and triads and of "giant" poiien grains in dipioid and tetraploid species (up to 7% in L. trichandra) shows that unreduced gametes are not uncommon in Leucaena. These resuits present for the first time a detaiied and comprehensive meiotic analysis for these Leucaena species and show how ciassicai cytogenetics may generate important data to be used in taxonomy, evolutionary studies and plant breeding.

Comportamento meiótico e fertilidade do pólen foram estudados em um total de 49 acessos de 14 taxa do gênero Leucaena, leguminosas arbóreas fixadoras de nitrogênio nativas da América Centrai. As dipióides L. macrophytia, L. pulverulenta, L. retusa, L. salvadorensis, L. shannonii e L. trichandra apresentaram pareamento cromossõmico regular, preferencialmente em bivalentes, mas quadrivaientes e outras anormalidades foram observados em freqüências variadas. Nas tetrapióides L. confertiflora, L. diversifoiia, L. invoiucrata, L. feucocephaia, L. paiiida e no híbrido L. x spontanea a associação cromossomica mais comum também foram bivalentes, mas quadrivalentes e outras anormalidades foram observadas em freqüências variadas. O acesso L. ? hybrid apresentou predominantemente várias irregularidades, como univaientes, muitivalentes e aderências cromossõmicas. Nas espécies dipióides a ocorrência de quadrivalentes pode apoiar sua origem paleopoliplóide. A presença de quadrivalentes nas espécies polipioides apóia urna origem aiotetrapióide "segmentar', mas a autopoiipioidia com subseqüente diploidização não pode ser totalmente descartada. O índice meiótico foi superior a 80% na maioria dos acessos, refletindo a regularidade meiótica. A fertilidade do pólen variou de 71 a 98%, com algumas exceções. A presença de até 19% de díades e tríades e de macropóiens em espécies dipióides e tetrapioides (até de 7% em L. trichandra) demonstram que gametas não reduzidos não são raros em Leucaena. Estes resultados apresentam peia primeira vez uma análise meiótica detalhada e abrangente para Leucaena e demonstram como a citogenética clássica pode fornecer dados importantes para estudos taxonõmicos, evolutivos e no melhoramento de plantas. / Meiotic behavior and poiien tertffity were studied in a total of 49 accessions of 14 taxa of the Central American nitrogen fixing muitipurpose tree genus Leucaena. The dipioid L. macrophylla, L. pulverulenta, L. recusa, L. saivadorensis, L. shannonii and L. trichandra presented regular chromosome pairing, mostiy in bivalents, but quadrivaients and other abnormaiities were observed in varying frequencies. In tetrapioid L. confertitiora, L. diversifolia, L. involucraã, L ieucocephaia, L. pallida and the hybrid L. x spontanea bivalents were also the most common chromosome associations, but quadrivaients and others abnormaiities were observed in varying frequencies. The L. ? hybrid accession presented a predominance of severa! irreguiarities, such as univalents, muitivalents and chromosome stickiness. In dipioid species the commom occurrence of quadrivalents couid support their paleopoiypioid origin. The presence of quadrivaients in poiypioid species supports a segmentai aiiotetrapioid origin, but autopolypioidy with subsequent diplodization cannot be ruled out. Meiotic indexes were mostiy over 80% refiecting the rather regular meiotic behavior. Poilen fertility ranged from 71 to 98%, with some exceptions. The presence of up to 19% dyads and triads and of "giant" poiien grains in dipioid and tetraploid species (up to 7% in L. trichandra) shows that unreduced gametes are not uncommon in Leucaena. These resuits present for the first time a detaiied and comprehensive meiotic analysis for these Leucaena species and show how ciassicai cytogenetics may generate important data to be used in taxonomy, evolutionary studies and plant breeding.

This study was undertaken to determine the effects and nutritive value of Leucaena leucocephala when it was incorporated in a total mixed ration (TMR) fed to milk goats. This was to test the use of Leucaena to substitute for oilseed cake meals (OSCM) which are believed to be expensive and generally unavailable in many parts of the rural areas of South Africa. Four trials were conducted at the University of Pretoria Research Farm and analyses were carried out at the Nutrition laboratory of the University of Pretoria. Leucaena forage contained enough nutrients to allow it to be used as a substitute for OSCM and to a large extent was also the source of protein and roughage in the TMR. The leaves of Leucaena had a higher crude protein, mineral and mimosine concentration but lower fibre content than the pods and twigs; while the air dried Leucaena forage had a higher crude protein and lower fibre content than sun dried forage. This study showed that there was a higher crude protein and mimosine concentration but a lower fibre concentration from the Leucaena harvested in summer than that harvested in autumn. Milk yield and quality was not adversely affected by the inclusion of Leucaena in the milk goat diet at the rate of 25% of the DM, with the exception of milk urea nitrogen. The inclusion of Leucaena decreased the milk urea nitrogen as compared to that shown from TMR without Leucaena. The body weight and body condition of lactating goats were also not affected by inclusion of Leucaena during the three phases of the lactation period. Therefore, the inclusion of Leucaena in the milk goat diet has been shown to support production of milk in terms of yield and quality which was similar to that of goats fed a commercial diet. There was no significant difference in milk composition in terms of milk lactose and milk protein for milk produced in the morning and afternoon between goats fed the two diets, even though the morning milk yield was higher than the afternoon yield because of the unequal milking intervals. However, the milk composition in terms of milk urea nitrogen, milk fat and somatic cell counts varied greatly between morning and afternoon milking. The apparent digestibility, average daily gain and feed conversion ratio of Saanen male goats were not affected by the inclusion of Leucaena in the TMR, as compared to the TMR without Leucaena. However the voluntary dry matter and nutrients intake were improved by the inclusion of Leucaena in the TMR. No toxicity of mimosine was observed during this study. The results of this study also showed that the inclusion of Leucaena in the total mixed ration had no effect on the carcass characteristics and meat quality of goats as compared to those fed a TMR containing OSCM. / Dissertation (MSc(Agric))--University of Pretoria, 2011. / Animal and Wildlife Sciences / unrestricted

Made available in DSpace on 2016-08-10T10:44:45Z (GMT). No. of bitstreams: 1 MAX VINICIUS DE PAULA ABREU.pdf: 1697992 bytes, checksum: ce7b9a79a60a8a03cf9c71827e0052c9 (MD5) Previous issue date: 2015-02-27 / The objective of this study was to investigate and evaluate the influence of different nickel concentrations on germination and initial growth of Leucaena leucocephala (Lam.) thee Wit., aiming its use in restoration projects of contaminated areas. Initially defined five treatments for nickel concentrations, A-0 mg.L-1(control), B-40 mg.L-1, C-80 mg.L-1, D-120 mg.L-1e E-200 mg.L-1. Each treatment had ten repetitions, where each experimental unit was considered as a plastic container (350 ML) containing, two filter paper discs and twenty scarified seeds of the species. Each recipient received 10 ML of nickel nitrate solution (Ni(NO3)2) according to its concentration and then were placed in a bench of plant Biology Laboratory at PUC-Goiás, until the collection of data on germination and early growth. The nickel containing different concentrations were obtained by diluting a standard stock solution (100.0 mg L-1) using (Ni(NO3)2). To verify the effect of nickel on the growth of L. leucocephala seedlings was mounted a second experiment using plants with 120 days after germination. For this, was performed the production of 80 seedlings in 40 plastic bags (20x15 cm) containing a mixture of sand and organic substrate (1.1), 2 seedlings being allocated in each plastic bag. The seedlings remain in the nursery of the Plant Biology Laboratory at PUC-Goiás for a period of 180 days and periodically received water and nutrient solution complete of Hoagland Fortnightly. Four treatments were set for nickel concentrations, A-0 mg.L-1 (control), B-100 mg.L-1 C-200 mg.L-1,D-400 mg.L-1, with 10 replicates for each treatment. The data were analyzed using ANOVA and Tukey at 5% significance level. The results showed that the germination and initial growth of L. leucocephala plants was not significantly affected by different concentrations of nickel, revealing that the species under study has considerable tolerance to this Heavy Metal without damage to their physiology and development, making promising its use in the recovery of areas contaminated by this element and creating sustainable alternative for remediation of these areas though Phytoremediation. / O objetivo deste estudo foi investigar e avaliar a influência de diferentes concentrações de níquel sobre a germinação e crescimento inicial de Leucaena leucocephala (Lam.) de Wit., visando sua utilização em projetos de recuperação de áreas contaminadas. Foram definidos cinco tratamentos em relação às concentrações de níquel: A-0 mg.L-1 (controle); B-40 mg.L-1, C-80 mg.L-1, D-120 mg.L-1 e E-200 mg.L-1. Cada tratamento teve dez repetições, onde cada unidade experimental foi considerada como sendo um recipiente plástico (350 mL) contendo dois discos de papel de filtro e vinte sementes escarificadas da espécie. Cada recipiente recebeu 10 mL de solução de nitrato de níquel (Ni(NO3)2) de acordo com a respectiva concentração e foram colocados em bancada do laboratório de Biologia Vegetal da PUC-Goiás até a coleta dos dados referentes à germinação e crescimento inicial. As diferentes concentrações contendo níquel foram obtidas pela diluição de uma solução estoque padronizada (100,0 mg.L-1 utilizando (Ni(NO3)2). Para verificar o efeito do níquel sobre o crescimento das mudas de L. leucocephala foi conduzido um segundo experimento utilizando plantas com 120 dias após a germinação. Para isso, foi realizada a produção de 80 mudas em 40 sacos plásticos (20x15 cm) contendo uma mistura de areia e substrato orgânico (1:1), com duas mudas em cada saco plástico. As mudas permaneceram no viveiro do Laboratório de Biologia Vegetal da PUC-Goiás por um período de 180 dias e receberam água periodicamente e solução nutritiva completa de Hoagland quinzenalmente. Foram definidos quatro tratamentos em relação às concentrações de níquel: A- 0 mg.L-1 (controle); B-100 mg.L-1, C-200 mg.L-1 e E-400 mg.L-1, sendo 10 repetições para cada tratamento. Os dados foram analisados através do teste de ANOVA e de Tukey ao nível de 5% de significância. Os resultados demonstraram que a germinação e crescimento inicial das plantas de L. leucocephala não foram afetadas significativamente pelas diferentes concentrações de níquel, revelando que a espécie em estudo possui considerável resistência a este metal pesado sem que haja danos à sua fisiologia e desenvolvimento, tornando promissor o seu emprego na recuperação de áreas contaminadas por este elemento e criando alternativa sustentável para remediação dessas áreas através da fitorremediação.

Made available in DSpace on 2017-07-10T17:37:09Z (GMT). No. of bitstreams: 1 Valdemir Aleixo.pdf: 13557960 bytes, checksum: cdf0545cf265f7d10d1a23d077c3da31 (MD5) Previous issue date: 2006-07-27 / Concern with increase carbon dioxide emissions has fostered several studies throughout scientific knowledge. The greenhouse effect is recognized as necessary for Earth surface colonization. However, modern day carbon dioxide and other greenhouse effect gases are blamed for atmosphere warming and its catastrophic effects. Both the Kyoto treat and the policy of Mechanism of Clean Development have instigated new approaches to reward actions that result in carbon sequestration. The objective of this study was to calculate simple allometric equations in order to estimate above and below ground dry biomass from Leucaena leucocephala individuals of various sizes from the Marechal Candido Rondon county. The results indicated that the decreasing order of leucaena biomass are stem > branches > roots > leaves. Independently of individual size, 24 % of total dry biomass sampled in this study was located below ground and 76 % above ground. Log transformed linear equations using CBH (circumference at breast height) as independent variable was statistically significant (P<0.05) to estimate leucaena total dry biomass / Atualmente, a preocupação com as emissões do dióxido de carbono (CO2) e o seu elevado nível de concentração na atmosfera tem impulsionado muitos estudos nas mais diversas áreas do conhecimento, com o intuito de barrar ou diminuir esse, que se torna, cada vez mais, um grande problema para a sociedade moderna. É de conhecimento que o CO2 contribui com o efeito estufa e, sem ele, não seria possível o desenvolvimento da vida na terra como a conhecemos hoje. Mas, a concentração dos gases efeito estufa chegou a níveis elevados e sua conseqüência certamente será desastrosa. O efeito estufa causa o aquecimento global do planeta terra e, em conseqüência disso, o descongelamento de geleiras, a desregulação climática, entre outros fatores que influenciam diretamente na evolução natural dos ecossistemas. Essa problemática é tema de discussão de toda comunidade científica e se intensificou a partir de 1997 com o estabelecimento do Protocolo de Kyoto (atualmente Tratado de Kyoto), que contempla em suas premissas o MDL (Mecanismo de Desenvolvimento Limpo) que visa favorecer a quem estiver cultivando espécies florestais. Este propósito trouxe grande expectativa para muitos pesquisadores, que direcionaram seus trabalhos a fim de construir modelos e sistemas para quantificação de biomassa e determinação do carbono fixado em espécies florestais. Este ensaio foi desenvolvido no Município de Marechal Cândido Rondon PR, com o objetivo de ajustar equações que permitam estimar a biomassa aérea e subterrânea (biomassa total) para Leucaena Leucocephala (Lam.) De Wit em diferentes tamanhos. A L. leucocephala é uma leguminosa perene, originária da América Central e foi dispersada para outras partes do mundo devido ao seu rápido crescimento, boa adaptação e grande diversidade na utilização. Por ser uma espécie exótica e invasora, atualmente a L. leucocephala vem dominando os ecossistemas, o que pode ser considerado um grande problema do ponto de vista biológico. Não foi encontrado na literatura informações sobre a quantificação de biomassa L. Ieucocephala, além de suas utilidades, principalmente como suplementação protéica na alimentação de animais. A fim de contribuir com informações sobre a biometria para L. leucocephala, o trabalho foi realizado por método direto (destrutivo), com posterior análise dos dados e ajuste de equações simples que tornaram possível estimar a biomassa em diferentes componentes e tamanhos. Para estimar a potencialidade da L. leucocephala na fixação do carbono, foi utilizado o fator de conversão 0,5, ou seja, 50% da biomassa é composta por carbono. Do total da biomassa e do carbono para L. leucocephala em diferentes tamanhos, 24% corresponde à porção da raiz, e 76% corresponde à porção aérea. De forma geral a biomassa total apresentou a seguinte distribuição: fuste > galhos > raízes > folhas

O presente trabalho tem por objetivo principal apresentar um processo de qualificação de peças estruturais das espécies emergentes Leucaena leucocephala, Corymbia maculata e híbrido torelliodora: Corymbia torelliana x Corymbia citriodora, através de ensaios simplificados a fim de profissionalizar o uso generalizado da madeira. O mercado madeireiro não dispõe de recursos técnicos e econômicos para oferecer, com critério de segurança, novas alternativas de madeiras. Cumpriu-se um exigente programa de métodos de ensaios laboratoriais conhecidos em normas e de novos procedimentos de ensaio de obra aliando vantagens econômicas, segurança e tempo. São apresentados ensaios de flexão não destrutivos e destrutivos em peças na condição real de uso em máquina universal de ensaio, em obra e em corpos de provas segundo recomendações da norma brasileira NBR 7190/97. Não houve diferenças significativas entre os métodos de ensaio, concluindo-se, por um lado, que dificilmente se conseguem corpos de prova totalmente isentos de defeitos e, por outro lado, que os ensaios de obra são plenamente confiáveis. Estabeleceram-se correlações entre módulo de elasticidade (EM0) e o módulo de ruptura (fM) e entre resistência à compressão (fc0) e o módulo de ruptura (fM), módulo de elasticidade (EM0), módulo de elasticidade na compressão (Ec0), resistência ao cisalhamento (fv0) e densidade aparente, a fim de determinarem-se as propriedades mecânicas obtidas por ensaios mais complicados a partir de ensaios mais simples e, assim minimizar custos e tempo. Os resultados corroboraram para que a madeira seja comercializada e qualificada pelo módulo de elasticidade (EM0) e módulo de ruptura (fM) para cálculos e dimensionamentos de estruturas de madeira, possibilitando otimização de material e maior segurança nas estruturas. As espécies estudadas são aptas para o mercado de madeira estrutural ficando evidenciado que o ensaio de obra constitui-se numa metodologia que pode ser facilmente utilizada a nível comercial e de obra. / The current study aims to present a qualification process of structural wood pieces of emerging species Leucaena leucocephala, Corymbia maculata and hybrid torelliodora (Corymbia torelliana x C. citriodora), through simplified tests to professionalize the generalized timber uses. The wood market, due to lack of technical and economic resources, cannot offer, with safety criteria, alternatives to timber sources. A demanding program of standard laboratory testing protocols was followed and new test procedures for field tests combining economic advantages, security and time were developed. Nondestructive and destructive bending tests are presented in timber pieces in the real use condition in the universal testing machine, in field tests and in specimens according to recommendations of the Brazilian standard NBR 7190/97. No significant differences between the test methods were observed, which implies, from one side, that is almost impossible to obtain entirely defect-free specimens and, from the other side, the field tests are fully reliable. Correlations were established between modulus of elasticity (EM0) and modulus of rupture (fM); and between compression strength (fc0) and modulus of rupture (fM), modulus of elasticity (EM0), modulus of elasticity in compression in parallel to the grain (Ec0), shear strength (fv0) and apparent density to determine the more complex mechanical properties from those simpler and thus reducing costs and time. The results contribute to timber marketing and qualification by the modulus of elasticity (EM0) and modulus of rupture module (fM) for calculations and dimensioning of wooden structures, enabling material optimization and higher structural safety. The studied species are suitable for the structural wood market becoming an evidence that the field tests constitute a methodology that can be easily used in commercial level and construction.

O presente trabalho tem por objetivo principal apresentar um processo de qualificação de peças estruturais das espécies emergentes Leucaena leucocephala, Corymbia maculata e híbrido torelliodora: Corymbia torelliana x Corymbia citriodora, através de ensaios simplificados a fim de profissionalizar o uso generalizado da madeira. O mercado madeireiro não dispõe de recursos técnicos e econômicos para oferecer, com critério de segurança, novas alternativas de madeiras. Cumpriu-se um exigente programa de métodos de ensaios laboratoriais conhecidos em normas e de novos procedimentos de ensaio de obra aliando vantagens econômicas, segurança e tempo. São apresentados ensaios de flexão não destrutivos e destrutivos em peças na condição real de uso em máquina universal de ensaio, em obra e em corpos de provas segundo recomendações da norma brasileira NBR 7190/97. Não houve diferenças significativas entre os métodos de ensaio, concluindo-se, por um lado, que dificilmente se conseguem corpos de prova totalmente isentos de defeitos e, por outro lado, que os ensaios de obra são plenamente confiáveis. Estabeleceram-se correlações entre módulo de elasticidade (EM0) e o módulo de ruptura (fM) e entre resistência à compressão (fc0) e o módulo de ruptura (fM), módulo de elasticidade (EM0), módulo de elasticidade na compressão (Ec0), resistência ao cisalhamento (fv0) e densidade aparente, a fim de determinarem-se as propriedades mecânicas obtidas por ensaios mais complicados a partir de ensaios mais simples e, assim minimizar custos e tempo. Os resultados corroboraram para que a madeira seja comercializada e qualificada pelo módulo de elasticidade (EM0) e módulo de ruptura (fM) para cálculos e dimensionamentos de estruturas de madeira, possibilitando otimização de material e maior segurança nas estruturas. As espécies estudadas são aptas para o mercado de madeira estrutural ficando evidenciado que o ensaio de obra constitui-se numa metodologia que pode ser facilmente utilizada a nível comercial e de obra. / The current study aims to present a qualification process of structural wood pieces of emerging species Leucaena leucocephala, Corymbia maculata and hybrid torelliodora (Corymbia torelliana x C. citriodora), through simplified tests to professionalize the generalized timber uses. The wood market, due to lack of technical and economic resources, cannot offer, with safety criteria, alternatives to timber sources. A demanding program of standard laboratory testing protocols was followed and new test procedures for field tests combining economic advantages, security and time were developed. Nondestructive and destructive bending tests are presented in timber pieces in the real use condition in the universal testing machine, in field tests and in specimens according to recommendations of the Brazilian standard NBR 7190/97. No significant differences between the test methods were observed, which implies, from one side, that is almost impossible to obtain entirely defect-free specimens and, from the other side, the field tests are fully reliable. Correlations were established between modulus of elasticity (EM0) and modulus of rupture (fM); and between compression strength (fc0) and modulus of rupture (fM), modulus of elasticity (EM0), modulus of elasticity in compression in parallel to the grain (Ec0), shear strength (fv0) and apparent density to determine the more complex mechanical properties from those simpler and thus reducing costs and time. The results contribute to timber marketing and qualification by the modulus of elasticity (EM0) and modulus of rupture module (fM) for calculations and dimensioning of wooden structures, enabling material optimization and higher structural safety. The studied species are suitable for the structural wood market becoming an evidence that the field tests constitute a methodology that can be easily used in commercial level and construction.