The biodiversity is distributed heterogeneously across the Earth. Although the discussion about which factors determine the spatial patterns of species diversity remains controversial, to know the components of biodiversity themselves is a challenge even bigger in certain regions. So, to know how much still remains to be studied or discovered is fundamental to the science, and the lack of knowledge about the species geographical distribution is known as one of the main problems faced in biodiversity research, especially in “Megadiverse” countries like Brazil. Historically, the Caatinga biome has been recognized as one of the most unknown and less valued according to its biodiversity, because the erroneous idea that the biome would have low diversity and endemism rates, and high degrees of degradation. Considering the dominance of the Family Fabaceae in the Caatinga, in both richness and abundance, we investigated the spatial pattern of Fabaceae species richness on the biome looking for determine which are the factors responsible for the spatial variation on its species richness. Moreover, we elaborated a spatial statistical model for the diversity of Fabaceae in the Caatinga, utilizing the spatial structure of the know assemblages and their environmental determinants, in order to estimate the shortfall of knowledge about the distribution (Wallacean shortfall) of the family in the Caatinga. We obtained 220,781 registers, less than 25% were valid. From these registers, we found 1,310 species in 198 genera. The predict richness vary from 92 to 283 species across the space and was better described by the sampling effort, the soil properties and the topography. With the measure of discrepancy between predicted and the observed values of species richness, we estimated the Wallacean shortfall, reaching 192 species in one single locality. The total number of species found in this work represents an expressive improvement on the know species richness of the family in the Caatinga. The selection of non-climatic factors as the main predictors of richness indicate the major influence of topography and soil on regional scale. The importance of substrate on the establishment of plant communities on the semiarid, as well. The estimated Wallacean shortfall evidences a chronical and spatially heterogeneous deficiency on knowledge of the regional flora. The persistence of such expressive gaps on the knowledge, plus the reduced coverage of protected areas on the biome shows a currently risk of significantly losses of biological diversity, with serious implications for the conservation of the biome. / A biodiversidade é distribuída de forma heterogênea através do planeta Terra. Embora a discussão sobre quais fatores determinam os padrões espaciais da biodiversidade continue controversa, o simples conhecimento dos seus componentes é um desafio ainda maior em algumas regiões. Assim, conhecer o quanto ainda há para ser estudado ou descoberto é fundamental para a ciência, e a falta de conhecimento sobre a distribuição geográfica das espécies é considerado um dos principais problemas enfrentados em estudos sobre a biodiversidade, especialmente em países “megadiversos” como o Brasil. O Bioma Caatinga tem sido historicamente reconhecido com um dos menos conhecidos e valorizados quanto a diversidade biológica, devido à ideia equivocada de sua baixa diversidade e endemismo e elevado grau de antropização. Considerando a dominância da família Fabaceae na Caatinga, quanto à riqueza e abundância regional, investigamos o padrão espacial da riqueza de espécies de Fabaceae no bioma, buscando determinar quais os fatores ambientais responsáveis pela variação espacial da sua riqueza de espécies. Além disso, elaboramos um modelo estatístico espacial de diversidade de Fabaceae na Caatinga a partir da estrutura espacial das assembleias conhecidas e dos seus determinantes ambientais, a fim de estimar o déficit de conhecimento sobre a distribuição (déficit wallaceano) da Família na Caatinga. Obtivemos 220.781 registros, dos quais menos de 25% foram válidos. A partir desses registros, encontramos o total de 1.310 espécies de 198 gêneros. A riqueza predita pelo modelo espacial variou de 92 a 283 espécies ao longo do espaço e foi melhor descrita pelo esforço amostral, aspectos do solo e topografia. A partir da medida de discrepância entre valores preditos e observados de riqueza de espécies, estimamos valores de déficit Wallaceano, chegando a 192 espécies em uma única localidade. O número total de espécies encontrado neste trabalho representa um incremento expressivo na riqueza conhecida de espécies da família na Caatinga. A seleção de fatores não climático como principais preditores de riqueza indica maior influência da topografia e do solo na escala regional. E também a importância do substrato no estabelecimento de comunidades vegetais no semiárido. O déficit Wallaceano estimado evidencia uma deficiência crônica e espacialmente heterogênea no conhecimento da flora regional. A persistência de lacunas tão expressivas no conhecimento, somada a cobertura reduzida de áreas protegidas no Bioma evidencia um risco corrente de perdas significativas de diversidade biológica com sérias implicações para a conservação do Bioma.

Submitted by (edna.saturno@ufrpe.br) on 2017-05-17T15:31:54Z No. of bitstreams: 1 Marta Gerusa Soares da Silva.pdf: 1019521 bytes, checksum: dafe6a7ce15446dca593cbcc3e9179b2 (MD5) / Made available in DSpace on 2017-05-17T15:31:54Z (GMT). No. of bitstreams: 1 Marta Gerusa Soares da Silva.pdf: 1019521 bytes, checksum: dafe6a7ce15446dca593cbcc3e9179b2 (MD5) Previous issue date: 2010-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The aim of this study was to evaluate the dynamics of the association of „capim-de-raiz‟ (Chloris orthonoton Doell.) and „capim-milhã‟ [Brachiaria plantaginea (Link.) Hitchc.], concerning growth, persistence and production, as well to morphanatomically characterize the legume „orelha de onça‟ (Macroptilium martii Benth.). In order to evaluate the dynamics of the association „capim-de-raiz‟ and „capim-milhã‟, two experiments were carried out: I. Evaluation of deferred native pasture concerning botanical composition and forage mass; II. Growth dynamics of „capim-milhã‟ and „capim-de-raiz‟. Experiment I was conducted at the Experimental Station of IPA, in São Bento do Una - PE from 2007 to 2008 with different evaluation periods for forage mass and botanical composition. Experiment II was conducted at a greenhouse in the Animal Science Department - UFRPE, from 09.26.06 to 07.26.07. Soil blocks with the plant community were taken from native pasture area of the Experimental Station of Instituto Agronômico de Pernambuco - IPA, in São Bento do Una - PE, and placed in plastic pots remaining at a greenhouse in UFRPE. Pots were submitted to four irrigation schedules: Irrigation I - irrigation at the beginning of the experiment; Irrigation II - started two months after Irrigation I; Irrigation III - started four months after irrigation I and Irrigation IV - started six months after irrigation I. After the initial irrigation of each period, all pots were irrigated every seven days until drainage and regrowth number, seedling number, plant number and inflorescence number were evaluated. Morphanatomical characterization of „orelha de onça‟ leaf was analyzed with optical microscopy in cross-sections confectioned laminae. 10 families, 15 genera and 18 species were identified in the deferred pasture. In botanical composition from May to August 2007, „capim-milhã‟ was the main component from 60 to 90 days with 46.75 and 52.09%, respectively. In August 2007, other species participated with 57.75% of the botanical composition; at the end of evaluation in year 2008 other species occupied 100% of the composition. The highest forage mass (kg DM/ha) for „capim-milhã‟ (2.736) occurred at 90 days, for other species (3.141) and „capim-de-raiz‟ (2.701) at 120 days. In soil blocks it was observed that regrowth occurred only after 30 days of assessment for initial irrigation and the highest number of seedlings to the pots occurred at 30 days. It was observed at 60 days the largest number of grasses for irrigation III and at 90 days for irrigation IV, and that most of inflorescence appeared at 90 days. In deferred area the use of stockpiled forage should preferably take place from 60 to 90 days. The main form of establishment of „capim-de-raiz‟ was by germination and at 150 days it was observed population growth of other species. It was observed paracytic and amphistomatic stomata, simple and uniseriate hairs, palisade and spongy chlorophyll parenchyma in „orelha de onça‟ leaf blade. In stem vascular system it was observed a range of libero-ligneous beams in the internodes area, separating cortex of medulla. Foliar and stem anatomical characteristics are common to legumes. / O objetivo deste trabalho foi avaliar a dinâmica da associação capim-de-raiz (Chloris orthonoton Doell.) e capim-milhã [Brachiaria plantaginea (Link.) Hitchc.], quanto ao crescimento, persistência e produção, bem como caracterizar morfoanatomicamente a leguminosa orelha de onça (Macroptilium martii Benth.). Para avaliar a dinâmica da associação capim-de-raiz e capim-milhã, foram realizados dois experimentos: I. Avaliação de um pasto nativo diferido quanto à composição botânica e massa de forragem; II. Dinâmica do crescimento do capim-milhã e capim-de-raiz. O experimento I foi conduzido na Estação Experimental do IPA, no município de São Bento do Una - PE, de 2007 a 2008, sendo utilizados diferentes períodos para avaliação da massa de forragem e composição botânica. O experimento II foi realizado em telado no Departamento de Zootecnia - UFRPE, durante o período de 26.09.06 a 26.07.07. Cubos de solos com a comunidade vegetal foram retirados de área de pastagem nativa, da Estação Experimental do Instituto Agronômico de Pernambuco - IPA, no município de São Bento do Una - PE, e colocados em vasos plásticos permanecendo em telado da UFRPE. Os vasos foram submetidos a quatro épocas de início de irrigação: Irrigação I ¿ irrigação por ocasião da implantação do experimento; Irrigação II ¿ iniciada dois meses após a irrigação I; Irrigação III ¿ iniciada quatro meses após a irrigação I e Irrigação IV ¿ iniciada seis meses após a irrigação I. Após a irrigação inicial de cada período, todos os vasos foram irrigados a cada sete dias até drenagem e foram avaliados o número de rebrotes, número de plântulas, número de plantas e número de inflorescências. A caracterização morfoanatômica foliar da orelha de onça foi analisada em microscopia óptica em lâminas confeccionadas em secções transversais. Foram identificadas 10 famílias, 15 gêneros e 18 espécies no pasto diferido. Na composição botânica de maio a agosto de 2007, o capim-milhã foi o componente principal dos 60 aos 90 dias com 46,75 e 52,09%, respectivamente. Em agosto de 2007, outras espécies participaram com 57,75% da composição botânica; no ano de 2008 ao final da avaliação, outras espécies ocuparam 100% da composição. As maiores massas de forragem (kg de MS/ha) para o capim-milhã (2.736) foram aos 90 dias, e para outras espécies (3.141) e capim-de-raiz (2.701) aos 120 dias. Nos cubos de solo, observou-se que o rebrote ocorreu apenas aos 30 dias de avaliação para irrigação inicial e o maior número de plântulas para os vasos ocorreu aos 30 dias. Foi observado aos 60 dias o maior número de gramíneas para irrigação III e aos 90 dias para irrigação IV, e que a maioria das inflorescências surgiu aos 90 dias. Em área diferida, o aproveitamento da forragem acumulada deve ocorrer preferencialmente dos 60 aos 90 dias. A principal forma de estabelecimento foi por germinação de sementes e aos 150 dias observou-se crescimento populacional de outras espécies. Foram observados na lâmina foliar da orelha de onça estômatos paracíticos e anfiestomáticos, pelos simples e unisseriados, parênquima clorofiliano em paliçada e esponjoso. Nos sistemas vasculares do caule observou-se, nas áreas dos entrenós, uma faixa de feixes líbero-lenhosos separando o córtex da medula. As características anatômicas foliares e caulinares são comuns às leguminosas.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Os diferentes solos e manejos culturais afetam o equilÃbrio entre solo e organismos endÃgenos, os quais, por sua vez afetam a sustentabilidade do solo. Desse modo acredita-se que a diversidade dos organismos do solo tenha uma relaÃÃo estreita com a diversidade de outros organismos, tanto na superfÃcie, quanto no prÃprio solo e que as interaÃÃes dessa diversidade microbiana possam levar a uma alteraÃÃo de funÃÃo reduzindo ou ampliando a sustentabilidade dos ecossistemas. InteraÃÃes mutualÃsticas sÃo muito comuns na natureza e desempenham importante papel em muitos processos de diversos ecossistemas. Desse modo, a identificaÃÃo dos padrÃes da estrutura espacial e abundÃncia de microrganismos à um elemento importante e, necessÃrio para identificar esse processo.AssociaÃÃes mutualÃsticas entre plantas e organismos do solo sÃo essenciais para a sobrevivÃncia e crescimento das plantas na maioria dos ecossistemas terrestres. Assim, o uso combinado de leguminosas e microrganismos na reabilitaÃÃo de solos deteriorados à um processo efetivo na reestabilizaÃÃo dos ciclos de nutrientes nesse sistema, pois a estrutura alimentar do solo pode afetar o desenvolvimento da vegetaÃÃo. O mutualismo entre rizÃbios e leguminosas à possÃvel de manipulaÃÃo experimental. Diferente de alguns mutualistas, rizÃbios podem crescer e ser cultivados em meios seletivos. AlÃm disso, seu comportamento mutualista dentro dos nÃdulos pode ser manipulado e monitorado de modo nÃo invasivo. objetivo deste trabalho foi avaliar a diversidade de estirpes nativas de rizÃbio e a relaÃÃo com algumas espÃcies de leguminosas arbÃreas nativas ocorrentes na Reserva Particular do PatrimÃnio Natural (RPPN) Serra das Almas (05 00â a 05 20â S e 40 48 a 41 12â W) no estado do Cearà (Brasil),em uma Ãrea de caatinga no municÃpio de CrateÃs-Ce, dista 390 Km de Fortaleza, entre cotas de 300 a 350 m de altitude, e que caracteriza-se pro apresentar clima semi Ãrido e pluviosidade mÃdia de 881 mm anuais distribuÃda de Janeiro a Abril. Foram identificadas oito espÃcies de leguminosas arbÃreas, que apresentaramassociaÃÃes com rizÃbios: Anadenanthera colubrina var. cebil (Griseb)Altschu (Angico), Bauhinia cheilantha (Bong.) Stend (MororÃ), Poincianella pyramidalis (Tul.) L.P. Queiroz (Catingueira), Erythrina velutina Willd. (Mulungu), Mimosa caesalpiniifolia Benth (SabiÃ), Minosa acustistipula (Mart.) Benth (Juremabranca), Mimosa tenuiflora (Willd.) Poir (Jurema-preta), Amburana Cearensis (AllemÃo) A.C. Smith (Emburana). Foram coletados nÃdulos e solo rizosfÃrico para a identificaÃÃo de bactÃrias diazotrÃficas, em dois perÃodos, na estaÃÃo chuvosa e na seca. Foi realizado o cultivo destes rizÃbios nas plantas-isca, Macropitillium atropurpureum (DC) Urban, Vigna unguiculata (L., Walp.), Cajanus cajan var. flavus DC e Mimosa pudica L, bem como a caracterizaÃÃo cultural caracterizaÃÃo cultural de estirpes de rizÃbio isolados, testes de tolerÃncia a nÃveis crescentes de NaCl e a altas temperaturas.Verificou-se que 92,42% dos isolados apresentara crescimento rÃpido e 52,24% acidificaram o meio 79. Um total de 84,93% isolados possuem tolerÃncia a altas temperaturas (45 C), e 90,75% isolados apresentaram tolerÃncia Ãs concentraÃÃes salinas a 5%.Os resultados obtidos demonstraram que hà relaÃÃo entre a tolerÃncia à salinidade e à temperatura quando avaliado in vitro para os isolados testados

O presente estudo teve como objetivo avaliar o efeito da inoculação com rizóbio no estabelecimento, crescimento inicial e em alguns aspectos da dinâmica de N em folhas de leguminosas (Fabaceae) arbóreas nativas plantadas por semeadura direta no campo, em área de mata ciliar no Estado de São Paulo. Foi avaliada a emergência de plântulas (% em relação ao número de sementes plantadas) até os 3 meses após a semeadura (MAS) e o crescimento em altura aos 13 MAS. O fracionamento isotópico do N foliar também foi avaliado, pelo método da abundância natural do 15N, além da concentração de N e a razão C/N foliar. Acacia polyphylla foi usada como planta-referência não-fixadora de N2. Em relação ao desenvolvimento inicial, houve grande variação entre as espécies estudadas. Acacia polyphylla e Enterolobium contortisiliquum apresentaram taxa de germinação mediana e rápido crescimento. Mimosa bimucronata e Parapiptadenia rigida tiveram crescimento relativamente rápido, porém baixo potencial germinativo. Erythrina speciosa e Poecilanthe parviflora, com crescimento lento, apresentaram germinação elevada no campo. As espécies fixadoras de N2 mostraram &#948;15 N médio de 2,7&#8240;, enquanto que a referência Acacia polyphylla se mostrou cerca de 4,0&#8240; mais enriquecida em 15N . Erythrina speciosa e Ormosia arborea apresentaram os menores valores de &#948;15N, enquanto que Parapiptadenia rigida, enriquecida em 15N, mostrou estar obtendo N exclusivamente do solo. Poecilanthe parviflora, Mimosa bimucronata e Enterolobium contortisiliquum apresentaram valores intermediários de &#948;15N, com grande variação entre os indivíduos amostrados. A concentração de N nos tecidos foliares variou entre 1,5% e 3,6%. De forma geral, esta variável não mostrou relação direta com o &#948;15N das plantas. A menor razão C/N foi observada em Enterolobium contortisiliquum e Erythrina speciosa, seguida por M. bimucronata. Nas condições experimentais locais, as plantas não responderam à inoculação com rizóbio em nenhum dos parâmetros avaliados (estabelecimento, crescimento inicial, &#948;15N, concentração de N e razão C/N). As espécies de crescimento mais lento e com alta incidência de herbivoria observados no campo (E. speciosa e O. arborea) foram também as que apresentaram &#948;15N na faixa considerada como de ocorrência da fixação biológica de nitrogênio. Os resultados indicam, para as outras espécies, maior aquisição de N proveniente do solo. / The aim of this work was to assess the effect of rhizobia inoculation on the establishment, early growth and some aspects of N dynamics in direct-seeded native legume (Fabaceae) trees in a riparian zone of São Paulo State, Southeastern Brazil. Seedling emergency (% of total planted seeds) was evaluated until three months after sowing (MAS), and the height of the trees were measured at 13 MAS. Isotopic N fractionation was also assessed by the 15N natural abundance method, as well as foliar N content and C/N ratio. Acacia polyphylla was used as a non-N2-fixing reference plant. Acacia polyphylla and Enterolobium contortisiliquum grew most rapidly, with moderate germination rate. Mimosa bimucronata and Parapiptadenia rigida were fast-growing but with low establishment rate. Erythrina speciosa and Poecilanthe parviflora showed low growing rate, but high germination potential. The N2-fixers showed an average foliar &#948;15N of 2,7&#8240;, while the reference-plant was 4,0&#8240; more <sup15>N enriched. Erythrina speciosa and Ormosia arborea showed the lowest &#948;15N values. The high &#948;15N of Parapiptadenia rigida probably indicated that it is obtaining N exclusively from the soil. Poecilanthe parviflora, Mimosa bimucronata and Enterolobium contortisiliquum showed intermediate &#948;15N values, with strong variations among the sampled individuals. Foliar N concentrations varied from 1,5% to 3,6%. In general, N concentrations were not correlated with foliar &#948;15N . The lowest C/N ratio was observed on E. contortisiliquum and E. speciosa , followed by M. bimucronata. In this field trial conditions, rhizobia inoculation did not show differences in all surveyed parameters (establishment, early growth, foliar &#948;15N, total N content and C/N ratio of trees). The slow-growing species, E. speciosa and O. arborea , that also had a high herbivore attack observed in the field, showed foliar &#948;15N in the biological N2 fixation range. The results suggested, for the other species, a larger soil N acquisition.

Made available in DSpace on 2017-07-10T17:47:58Z (GMT). No. of bitstreams: 1 Camila_Ducati.pdf: 1229241 bytes, checksum: 0880bcc64cf9d89389cf4eef6e2a7e0b (MD5) Previous issue date: 2014-02-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Were conducted for two years, with two studies to evaluate the use of oat long cycle Iapar 61 single or grown in association with legumes birdsfoot trefoil, with planting of corn in succession as a summer crop. The first study evaluated the structural, production characteristics, nutritional value of oat (Avena strigosa Iapar 61) grown single or associated with birdsfoot trefoil (Lotus corniculatus cv. St. Gabriel). The second experiment was conducted in two years with the aim to evaluate the structural , production characteristics , gas exchange IRGA (Infra Red Gas Analyser , Li - 6400XT , Licor , Lincoln , Nebraska) and chlorophyll content (SPAD index) of maize grown in succession to winter crops mentioned above . In the first experiment, two courts of oats in the first year and grazing periods in the second year, with average intervals of 30 days. The experimental design was a randomized complete block design with split plot, with the first year: two cropping systems: single or intercropped with birdsfoot trefoil with two periods of four replicates and oats oatmeal. In the second year, four tillage systems: conventional tillage oats, oat stubble tillage on corn, oats overseeded area of birdsfoot trefoil and single, with three cycles of growth and four replications. In the second study with corn, the experimental design used in the first and second year was a randomized split plot with blocks respectively. The following winter crops Corn was studied in succession: oat conventional tillage, no-till oats, oats in combination with birdsfoot trefoil, birdsfoot single, oats associated with nitrogen fertilization on ryegrass and oats associated with ryegrass nitrogen fertilization, with four replications. After planting corn the second year, we assessed the structural features for 70 days. Before the corn harvest, were picked manually ears of corn in three rows of four meters, which evaluated the number of grain rows, number of kernels per row, ear diameter, ear length, subsequent to these reviews, was made the threshing of grain for measurement of productivity data. The findings of the first study show that oats have reduced their production when combined with birdsfoot dry matter, but the total production (oat + birdsfoot trefoil) equates to the other treatments. In the first year dry matter yield of oats was higher when associated with birdsfoot the second cut (3750 kg ha - 1) compared to that obtained in the tillage of oat (2599 kg ha -1). In the second year, the highest dry matter production of oat occurred before the second grazing under no-tillage (4451.98 kg ha - 1). Oats elevates the apical meristem with the succession of grazing or cutting. The oat presents before the first grazing, high nutritional value, with high average levels of protein (22.25 %) for all treatments. However, at the end of its cycle the association of birdsfoot trefoil with oats, helped to raise the crude protein content of forage as this is in the final stage of its cycle. In vitro digestibility of DM was high for both oat grown under conventional tillage (73.04 %) and direct (77.05 %), and for birdsfoot trefoil (78.37 %), but decreased at the end of the cycle oat. There was no benefit to the cultivation of corn grown after legume and should performed new tests assessing possible causes, including allelopathic effect and competition among plants / Foram conduzidos por dois anos, dois estudos com o objetivo de avaliar o uso da aveia preta de ciclo longo Iapar 61 cultivada solteira ou em associação com a leguminosa cornichão, com plantio do milho em sucessão como cultura de verão. No primeiro estudo avaliaram-se as características estruturais, produtivas, valor nutricional da aveia preta (Avena strigosa Iapar 61) cultivada solteira ou associada ao cornichão (Lotus corniculatus cv. São Gabriel). O segundo experimento foi conduzido em dois anos com o objetivo de avaliar as características estruturais, produtivas, trocas gasosas IRGA (Infra Red Gas Analyser, Li-6400XT, Licor, Lincoln, Nebrasca) e teor de clorofila (Índice SPAD), do milho cultivado em sucessão aos cultivos de inverno citados anteriormente. No primeiro experimento avaliou-se dois cortes da aveia preta no primeiro ano e períodos de pastejo no segundo ano, com intervalos médios de 30 dias. O delineamento experimental foi em blocos casualizados com parcelas subdivididas no tempo, sendo no primeiro ano: dois sistemas de cultivo: aveia solteira ou aveia consorciada com cornichão com dois períodos de avaliação e quatro repetições. No segundo ano, quatro sistemas de cultivo: aveia plantio convencional, aveia plantio direto sobre palhada do milho, aveia sobressemeada em área de cornichão e cornichão solteiro, com três ciclos de crescimento e quatro repetições. No segundo estudo com milho, o delineamento experimental adotado no primeiro e segundo ano foi em blocos casualizados com parcelas subdivididas no tempo respectivamente. O milho foi estudado em sucessão as seguintes culturas de inverno: aveia preta plantio convencional, aveia preta plantio direto, aveia em associação com cornichão, cornichão solteiro, aveia associada com azevém com adubação nitrogenada e aveia associada com azevém sem adubação nitrogenada, com quatro repetições. Após o plantio do milho do segundo ano, avaliou-se as características estruturais por 70 dias. Antes da colheita do milho, colheram-se manualmente as espigas de três fileiras de milho em quatro metros, onde avaliaram-se o número de fileira de grãos, número de grãos por fileira, diâmetro de espiga, comprimento de espiga, posterior a essas avaliações, foi realizada a trilhagem das espigas para mensuração dos dados de produtividade. Os resultados encontrados no primeiro estudo demonstram que a aveia tem sua produção de matéria seca reduzida quando em associação com o cornichão, mas a produção total (aveia+cornichão) iguala-se aos demais tratamentos. No primeiro ano a produção de matéria seca da aveia preta foi superior quando associada com cornichão no segundo corte (3750 kg ha-1) em comparação ao obtido no sistema de plantio direto da aveia preta (2599 kg ha-1). No segundo ano, a maior produção de matéria seca da aveia preta ocorreu antes do segundo pastejo sob sistema de plantio direto (4451,98 kg ha-1). A aveia eleva o meristema apical com a sucessão de pastejos ou cortes. A aveia preta apresenta antes dos primeiros pastejos, elevado valor nutricional, com altos teores médios de proteína (22,25%) em todos os tratamentos. Entretanto, no final do seu ciclo a associação do cornichão com a aveia, contribuiu para elevar os teores de proteína bruta da forragem visto que esta encontra-se em estágio final do seu ciclo. A digestibilidade in vitro da MS foi elevada tanto para aveia preta cultivada sob sistema de plantio convencional (73,04%) e direto (77,05%), quanto para o cornichão (78,37%), decrescendo com o final do ciclo da aveia. Não foi verificado benefícios para o cultivo do milho em sucessão a leguminosa, devendo realizados novos ensaios avaliando possíveis causas, entre elas efeito alelopático e competição entre plantas

Made available in DSpace on 2016-04-26T19:39:29Z (GMT). No. of bitstreams: 1 2006-Luciano Lopes Reis.pdf: 1765828 bytes, checksum: e031c34734485e7d84bd20e5fcc0d59b (MD5) Previous issue date: 2006-02-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This study had as objective to monitor the process of environmental reclamation of tanks filled with residues from bauxite washings, vegetated by hydro-sowing legume trees species inoculated with rhizobia, and asbuscular mycorrhizal fungi. Nutrient fertilizers, without nitrogen, were added at the mixture at sowing. Later it was planted a mixture of native tree species seedlings, with a high proportion of N2-fixing legumes, in an experiment with additional increasing levels of fertilizers and liming, except for nitrogen. The deposits of sterile bauxite subsoil, vegetated with the mix of native species, with high proportion of legumes capable of N2 fixation and mineral fertilization, were evaluated at different periods of time, for the chemical and biological attributes of soil and plants. Samples of soil, leaves, litter, and soil invertebrates fauna were taken in 2002, 2003 and 2004, to measure nutrient availability in soil; foliar nutrient level of indicator plants; soil microbial biomass and activity; soil fauna activity, diversity and ecological indexes; and evaluation of vegetal coverage of the SP1 residue tank. The results of foliar analyses indicated that even at the highest level of fertilizer and lime additions in the SP1 residue tank were not sufficient to meet the adequate plant nutrition requirements, indicating the need of higher input of nutrients. By using multivariate statistical analyses of the data, it was possible to distribute the studied systems along Cartesian axis, where the native forest area, used as testimony, and old vegetated mining sites (planted in 1984, 1992 and 1994) were clustered together; while the most recent vegetated mining sites and the tanks filled with residues formed a distant cluster. Among the index attributes studied Al+3, total C, total N, K, soil pH, microbial carbon and respiration; and Ca and Mg from litter were the principal factors determining the ordering and distinction between reclamation sites. The reclamation methodology used in the residue tank SP1, which combined the hydro-sowing with application of low solubility fertilizers, using a mix of seeds from medium cycle legume trees inoculated and with mycorrhizae, with later planting of native seedlings and manual dispersion of seeds, showed to be an important technique to stimulate natural vegetation growth. Also, the technique resulted in a high capacity of addition of decidual material, and the legume tree Acacia holosericea showed the best capacity for soil coverage and input of nutrients. / Com o objetivo de monitorar o processo de recupera??o ambiental de tanques de dep?sito de rejeito da lavagem da bauxita, revegetados atrav?s da hidrossemeadura de leguminosas fixadoras de N2 e com adi??o de fungos micorrizicos, mais aporte de nutrientes. Posteriormente, foi feito o plantio de mudas nativas em experimento de n?veis de aduba??o e calagem, sem aplica??o de nitrog?nio. Os dep?sitos de subsolo est?ril em bauxita revegetados com mistura de esp?cies nativas, com grande propor??o de leguminosas fixadoras de N2 e aduba??o mineral na cova, avaliados em diferentes idades, foram utilizados atributos qu?micos e biol?gicos do solo e planta. Foram realizadas coletas de solo, de folhas, de serapilheira e da fauna de invertebrados do solo, nos anos de 2002, 2003 e 2004, para determina??o da disponibilidade de nutrientes no solo; dos teores foliares de nutrientes das plantas indicadoras; da biomassa e atividade microbiana; da atividade, diversidade de grupos e ?ndices ecol?gicos da comunidade da fauna do solo; e avalia??o da cobertura vegetal do tanque de rejeito SP1. Os resultados da an?lise foliar das esp?cies indicadoras e de disponibilidade de nutrientes no solo indicaram que nem os maiores n?veis de aduba??o e calagem utilizados no experimento do tanque de rejeito SP1 foram suficientes para permitir uma adequada nutri??o ?s plantas, indicando a necessidade de novos aportes de nutrientes. Atrav?s da aplica??o de ferramentas de estat?stica multivariada aos dados, foi poss?vel ordenar os sistemas estudados ao longo de eixos cartesianos, onde a ?rea de mata nativa, usada como testemunha, e reflorestamentos sobre res?duos de minera??o com maior idade (realizados nos anos de 1984, 1992 e 1994) se ordenam pr?ximos uns dos outros, enquanto que os reflorestamentos sobre est?ril mais recentes e ?reas dos tanques de rejeito se ordenam distantes destes, formando grupamentos entre si. Dentre os atributos indicadores utilizados, o Al+3, C total, N total, K e pH do solo; a respira??o e carbono microbiano; e o Ca e Mg da serapilheira foram os mais determinantes para o ordenamento e distin??o entre os sistemas em recupera??o. A metodologia de recupera??o utilizada no tanque de rejeito SP1 que combinou a pr?tica da hidrossemeadura com aplica??o de formas de adubos pouco sol?veis, utiliza??o de coquetel de sementes de leguminosas arb?reas de ciclo m?dio inoculadas e micorrizadas, posterior plantio de mudas nativas e lan?amento manual de sementes, mostrou-se como importante t?cnica propulsora da regenera??o natural. A t?cnica tamb?m resultou em elevada capacidade de aporte de material decidual, sendo a leguminosa arb?rea Acacia holosericea, a esp?cie que apresentou melhor capacidade de cobertura do solo e aporte de nutrientes.

La séquestration du C dans les sols réduit les effets du changement climatique, et améliore la qualité du sol. L'introduction des prairies temporaires dans le cycle des cultures pourrait améliorer les matières organiques du sol (SOM). L'objectif de la thèse était d'évaluer l'impact des modes de gestion de prairies temporaires sur la quantité, la composition et les processus de stabilisation des SOM et les émissions de gaz à effet de serre (GHG).Mes résultats montrent un arrière effet de la gestion des prairies temporaires sur les SOM après 3 ans de culture. La durée des prairies influence la quantité et la composition de la biomasse microbienne ainsi que la nature des SOM. La fertilisation en N de la prairie est nécessaire à la séquestration du C dans le sol sans augmenter les émissions de GHG.Pour remplacer la fertilisation en N minérale, des légumineuses peuvent être utilisées. En conséquence, je me suis intéressée à l'effet de la luzerne sur les formes de C, de N et de P dans les sols sous mélanges luzerne-graminées. Mes résultats indiquent une absence d'augmentation du stock de C dans les sols sous mélanges comparés aux monocultures de graminées fertilisées, malgré une plus forte productivité de la luzerne. Les biomarqueurs moléculaires indiquent que l'introduction de la luzerne en prairie influence la dégradation des SOM plus que leur stabilisation. De plus, la luzerne influence fortement les formes du P dans les sols sous mélanges.Ainsi, lors de l'introduction de prairie dans les cycles de culture, il est important d'optimiser les modes de gestion afin de faire le bon compromis entre le stockage du C, les émissions de GHG et l'utilisation d'engrais. / Soil C sequestration reduces the effects of climate change, improves soil quality and food security. Soil organic matter (SOM) could be enhanced by introduction of ley grassland into the cropping cycle. The objective of this PhD thesis was to evaluate the effect of management practices of ley grassland on the quantity, composition and stabilization processes of SOM and greenhouse gas emissions (GHG). My data showed legacy effects of duration and fertilization of the temporary grassland phase on SOM after 3 years of cropping. The duration of grassland phase influenced the quantity and composition of the microbial biomass as well as the nature of SOM. N fertilization during the grassland phase is necessary for soil C sequestration in soil without increasing GHG emissions.To replace mineral N fertilization, legumes may be used in forage production systems. Consequently, I was interested in the effect of introduction of lucerne on C, N and P forms in soils under lucerne-grass mixtures. My results indicate similar soil C stocks under mixtures and grass monocultures, despite the high productivity of lucerne. Molecular biomarkers indicated that the introduction of lucerne in grassland influenced the degradation of the SOM more than its stabilization. Moreover, the presence of lucerne influenced P forms in soils under mixtures.In conclusion, the introduction of ley grasslands into cropping cycles requires careful evaluation of the management practices in order to optimize C storage, GHG emissions and N fertilizer use.

Lectins are multivalent carbohydrate binding proteins that specifically recognise diverse sugar structures and mediate a variety of biological processes, such as cell-cell and host-pathogen interactions, serum glycoprotein turnover and innate immune responses. Lectins have received considerable attention in recent years on account of their properties leading to wide use in research and biomedical applications. Seeds of leguminous plants are mainly rich sources of lectins, but lectins are also found in all classes and families of organisms. Legume lectins have similar tertiary structures, but exhibit a large variety of quaternary structures. The carbohydrate binding site in them is made up of four loops, the first three of which are highly conserved in all legume lectins. The fourth loop, which is variable, is implicated in conferring specificity. Legume lectins which share the same monosaccharide specificity often exhibit markedly different oligosaccharide specificities. This thesis primarily concerns with structure solution and analysis of lectins from the legume and β-prism II fold families using X-ray crystallography. Apart from having the property of specifically and reversibly binding to carbohydrates, lectins are also interesting models to study sequence-structure relationships, especially of how minor change in the sequence may bring about major changes in oligomerization and binding. Chapter 1 gives an overview of different structural types of plant lectins and describes in detail, their carbohydrate binding features. The details of the various experimental procedures employed during the course of this research, are explained in Chapter 2. Chapter 3 describes the crystal structure of a β-prism II fold lectin (RVL), from Remusatia vivipara, an epiphytic plant of traditional medicinal value, and analysis of its binding properties. This lectin was established to have distinct binding properties and has nematicidal activity against a root-knot nematode with the localization site identified as the high-mannose displaying gut-lining in the nematode. The crystal structure of RVL revealed a new quaternary association of this homodimeric lectin, different from those of reported β-prism II lectins. Functional studies on RVL showed that it fails to bind to simple mannose moieties yet showed agglutination with rabbit blood cells (which have mannose moieties on the surface) and some high mannose containing glycoproteins like mucin and asialofetuin. Further, ELISA and glycan array experiments indicated that RVL has high affinity to N-glycans like trimannose pentasaccharide such as in gp120, a capsid glycoprotein of HIV virus, necessary in virus-association with the host cell. The structural basis for this N-glycan binding was revealed through structure analysis and molecular modelling, and it was demonstrated that there are two distinct binding sites per monomer, making RVL a truly multivalent lectin. Evolutionary phylogeny revealed the divergence in the β-prism II fold proteins with regards to the number of sugar-binding regions per domain, oligomerization and specificity. Chapter 4 deals with the structural studies on a galactose-specific legume lectin (DLL-II) from Dolichos lablab, a leguminous plant. The lectin was found to be a planar tetramer in the crystal structures of the native and ligand bound forms, as expected from our solution studies and phylogenetic analysis. The protein is a heterotetramer with subunits differing only in the presence or absence of a C-terminal helical region at the core of the tetramer. Due to the static disorder in all the crystals, the central helix could be oriented in either direction. Structure analysis of DLL-II proved to be an interesting endeavour as static disorder compounded with twinning in the crystal made the data processing and structure solution a challenging process. Subsequent structure and sequence alignments led to the identification of an adenine-binding pocket in the hydrophobic core of the tetramer. Based on this, DLL-II lectin was co-crystallized with adenine and the structure revealed the presence of adenine at the predicted binding site. Chapter 5 describes the identification and analysis of potential plant lectins/lectin-like domains in the genome of Oryza sativa, using bioinformatics approaches. This project was initiated to study the occurrence of legume-lectin like domains (a predominant dicot feature) in O. sativa, which is a monocot. Later, a large scale genome analysis for all types of lectin domains was carried out through exhaustive PSI-BLAST, profile matching by HMMer, CDD and MulPSSM. The final validation was carried out by assessing the carbohydrate binding potential of the domain by examining the sugar binding sites. The primary interest in undertaking this work was to find the occurrence of association of these domains with other domains as in protein receptor kinases, where lectin is the receptor domain. Though primarily initiated as a bioinformatics project, further structural characterization was attempted by cloning, expression and purification of some of the annotated lectin proteins using prokaryotic expression systems. The protein expression was attained in reasonable amounts for a few of the annotated legume lectin homologs, however purification is yet to be achieved as the expressed proteins are insoluble. A part of the results described in this thesis and the other related projects that the author was involved are reported in the following publications. 1) Purification, characterization and molecular cloning of a monocot mannose-binding lectin from Remusatia vivipara with nematicidal activity Bhat GG, Shetty KN, Nagre NN, Neekhra VV, Lingaraju S, Bhat RS, Inamdar SR, Suguna K, Swamy BM. 2010. Glycoconjugate J. 27(3):309-320 2) Modification of the sugar specificity of a plant lectin: structural studies on a point mutant of Erythrina corallodendron lectin Thamotharan S, Karthikeyan T, Kulkarni KA, Shetty KN, Surolia A, Vijayan M & Suguna K. 2011. Acta Crystallographica D 67(3):218-227 3) Crystal structure of a β-prism II lectin from Remusatia vivipara Shetty KN, Bhat GG, Inamdar SR, Swamy BM, Suguna K. 2012. Glycobiology 22(1): 56-69. 4) Structure of a galactose binding lectin from Dolichos lablab Shetty KN, Lavanyalatha V, Rao RN, SivaKumar N & Suguna K (Under review) 5) Occurrence of lectin-like domains: Oryza sativa genome analysis. Shetty KN & Suguna K. (Manuscript in preparation)

Les légumineuses peuvent interagir avec les bactéries du sol de la famille des Rhizobiaceae. Cette interaction aboutit à la formation d'un organe spécialisé appelé nodosité. Au sein des cellules symbiotiques des nodosités, les rhizobia sont capables de fixer l'azote atmosphérique et de la convertir en ammoniac, qui est une source d'azote assimilable par les plantes. Chez la Légumineuse Medicago truncatula, les cellules symbiotiques produisent une large famille de peptides riches en cystéines appelées (NCRs) spécifiquement exprimés dans les nodosités. Ces NCRs induisent la différenciation des bactéroïdes qui se traduit par un allongement cellulaire couplé à une forte endoréplication du génome (les bactéroïdes deviennent polyploïdes) contribuant ainsi à une augmentation importante de la taille des cellules, ainsi qu’une perméabilité membranaire accrue et une perte de toute capacité reproductrice. Les peptides NCRs ressemblent à des défensines, des peptides antimicrobiens, acteurs clés de l’immunité innée. L'analyse de l'expression de 334 gènes NCR dans 267 différentes conditions expérimentales en utilisant la base de données MtGEA (Medicago truncatula Gene Expression Atlas) a révélé que l'ensemble des gènes NCR testés (sauf quatre) n'est exprimé que dans les nodosités, ils ne sont pas exprimés dans d’autres organes de la plante, ni lors d’une infection par des agents pathogènes. De plus l’expression des NCRs n’est induite en réponse à aucune interaction biotique ou abiotique testée ou à des facteurs Nod. Les gènes NCR sont activés en vagues successives au cours de l’organogenèse nodulaire et ce profil temporel est en corrélation avec une localisation spatiale spécifique de leurs transcrit de la zone apicale à la partie proximale de nodosités. En outre, nous avons montré que les NCRs ne sont pas induites pendant la sénescence des nodules. Ces analyses expérimentales ensemble avec des calculs d’entropie de Shannon, une métric pour la spécificité d’expression, montrent que les gènes NCR sont parmi les gènes les plus fortement et le plus spécifiquement exprimés chez M. truncatula. Ainsi, l'expression des NCRs est soumise à une régulation extrêmement stricte et ils sont activés exclusivement pendant l’organogenèse et au cours du développement nodulaire dans les cellules symbiotiques polyploïdes. Cette analyse a suggéré l'implication de la régulation épigénétique des gènes NCR. La formation des cellules symbiotiques s'exerce par une endoreplication et est associée à une reprogrammation transcriptionnelle. En utilisant le tri par cytométrie en flux des noyaux, en fonction de leur contenu en ADN, nous avons montré que les vagues transcriptionnelles sont en correlation avec les niveaux croissants de ploïdie et resultent des modifications épigénétiques durant les cycles d’endoréplication. Nous avons étudié la méthylation de l'ADN génomique et l'accessibilité à la chromatine, ainsi que la présence des marqueurs répresseurs (H3K27me3) ou activateurs transcriptionnels (H3K9ac) sur des gènes spécifiques des nodosités. La méthylation différentielle de l'ADN n'a été trouvée que dans un petit sous-ensemble de gènes symbiotiques spécifiques aux nodosités. Néanmoins, plus que la moitié des gènes NCR était différentiellement méthyles. D'autre part, l'expression des gènes était corrélée avec la décondensation de la chromatine (ouverture), un enrichissement du marqueur H3K9ac et une diminution du marqueur H3K27me3. Nos résultats suggèrent que l’endoréplication, pendant la différenciation cellulaire dans les nodosités, fasse partie des mécanismes qui lèvent l’inactivation transcriptionnelle des gènes spécifiques des nodosités, ceci résultant de modifications des codes épigénétiques au niveau de la chromatine. / Legume plants are able to interact with soil bacteria from the Rhizobiaceae family. This interaction leads to the development of a specialized organ called root nodule. Inside the symbiotic nodule cells, rhizobia are capable to fix atmospheric nitrogen and convert it to ammonia, which is a usable nitrogen source for the plant. In the legume Medicago truncatula the symbiotic cells produce high amounts of Nodule-Specific Cysteine-Rich (NCR) peptides which induce differentiation of the rhizobia into enlarged, polyploid and non-cultivable bacterial cells. NCRs are similar to innate immunity antimicrobial peptides. The NCR gene family is extremely large in Medicago with about 600 genes. The expression analysis of 334 NCR genes in 267 different experimental conditions using the Medicago truncatula Gene Expression Atlas (MtGEA) revealed that all the NCR genes except five are exclusively expressed in nodules. No NCR expression is induced in any other plant organ or in response to biotic, abiotic stress tested or to Nod factors. The NCR genes are activated in consecutive waves during nodule organogenesis, which correlated with a specific spatial localization of their transcripts from the apical to the proximal nodule zones. Moreover, we showed that NCRs are not induced during nodule senescence. According to their Shannon entropy, a metric for tissue specificity, NCR genes are among the most specifically and highest expressed genes in M. truncatula. Thus, NCR gene expression is subject to an extreme tight regulation since they are only activated during nodule organogenesis in the polyploid symbiotic cells. This analysis suggested the involvement of epigenetic regulation of the NCR genes. The formation of the symbiotic cells is driven by endoreduplication and is associated with transcriptional reprogramming. Using sorted nodule nuclei according to their DNA content, we demonstrated that the transcriptional waves correlate with growing ploidy levels and investigated how the epigenome changes during endoreduplication cycles. We studied genome-wide DNA methylation and chromatin accessibility as well as the presence of repressive H3K27me3 and activating H3K9ac histone tail modifications on selected genes. Differential DNA methylation was found only in a small subset of symbiotic nodule-specific genes, including over half of the NCR genes, while in most genes DNA methylation was unaffected by the ploidy levels and was independent of the genes’ active or repressed state. On the other hand, expression of these genes correlated with ploidy-dependent opening of the chromatin and in a subset of tested genes with reduced H3K27me3 levels combined with enhanced H3K9ac levels. Our results suggest that endoreduplication-dependent epigenetic changes contribute to transcriptional reprogramming in differentiation of symbiotic cells.

Thesis (Ph.D. Agriculture (Plant Production)) -- University of Limpopo, 2022 / Livestock has evolved to serve as the foundation and backbone of human well-being, and it is an important component of South Africa's agricultural sector. The small stock such as sheep (Ovis aries) in Limpopo province has remained a significant and multifunctional livelihood strategy for the majority of the rural and resource-poor people. Factors such as population growth, urbanization, rising per capita income and changes in consumer tastes and preferences are all contributing to gradual increases in livestock product consumption and demand. According to the 2019 Abstract of Agricultural Statistics, South Africa is an importer of sheep and sheep products. If the sheep production industry in the province could pursue this opportunity and realize its full production potential then increased production could stimulate economic growth and development, particularly from the communal and smallholder sector. Objective one of the study seeks to describe the demographic and socio-economic characteristics of communal and smallholder sheep farmers, identify sheep feeding practices and describe the constraints that hinder the sustainable productive growth of communal and smallholder sheep systems. Data were collected from one hundred and twenty (120) sheep farmers using a structured questionnaire across three agro-ecological zones of Limpopo province. Results revealed that overall, the majority of sheep farmers were males (78%) and farmers were above 60 years old (48%). Mean sheep flock size differed significantly between communal (24.74) and smallholder (62.36) farmers. Indigenous crossbreeds were the dominant breed kept by communal (86%) and smallholder (77%) farmers. The majority of communal and smallholder farmers (90% and 96%, respectively) reared their sheep under an extensive system with rangelands as the main source of feed. As a result, they experience a critical feed gap during June and September, the mid-winter to early spring until the first rains. The findings of the study revealed that feed shortages and diseases were ranked as the first and second production constraints by sheep farmers in both the production systems. In rangeland-dependent feeding systems, insufficient feed to meet animal demands create a feed gap, which is a critical factor that limits sheep productivity and causes xxi land degradation through overgrazing. Improved forages have been widely advocated as a critical step toward resolving this challenge. However, the adoption and utilization of improved technologies such as on-farm forage legume production by these farmers have been very low, contributing to the province's low sheep productivity. An extension of objective one of this study used primary data which was collected from a sample of 120 sheep farmers to determine the factors that influence the adoption of on-farm forage legume production and the perceived barriers to adoption by communal and smallholder sheep farmers in the Limpopo province. A Probit regression model and Principal Component Analysis (PCA) were used to analyze the data. The study revealed that the adoption of on-farm forage production by communal and smallholder sheep farmers is influenced by several factors, including gender, farming experience, knowledge of forage legume production, source of income, membership in farmer associations, access to extension services and farm size. Farmer perceived barriers to adoption of on-farm forage legume production identified by this study were low institutional support, lack of resources, lack of knowledge, shortage of water and objectives of the farmer. It is therefore recommended that intensive and high-quality extension support in partnership with industry associations and stakeholders is required for communal and smallholder farmers to improve forage technology awareness, training and promote on-farm forage production to transform communal and smallholder sheep feeding practices. In the face of climate change, identifying forage species with a high potential to mitigate winter feed gap challenges under more variable climatic conditions is critical. Trifolium and Vicia species are forage legumes well known for producing high-quality forage, particularly protein, which is deficient in the majority of feed resources used for sheep feeding during the winter season. Climate change-induced stresses from rising temperatures, which these winter annual forage legumes are likely to face, necessitate agronomic and breeding approaches to improve their adaptability. Lack of knowledge on how these climate change mitigation approaches influence the productivity of winter annual forage legumes in the Pietersburg Plateau of Limpopo province prompted objective two of this study. A three-year field experiment laid in a split-split plot design with four replications was conducted to measure the effects of planting date, cultivar and harvest stage on the physiological traits associated with biomass production, forage quality, nodulation activity and xxii nutritive value of annual clover and vetch species. The results showed that the planting date and harvest stage had a significant effect on leaf gaseous exchange and biomass production. A non-significant effect of planting date on nutritive value was observed. Intercellular CO2 concentration, transpiration rate, stomatal conductance, instantaneous water use efficiency and intrinsic water use efficiency in cultivars increased with delayed planting, while a decrease in photosynthetic rate, shoot DM, root DM and nodule DM was observed. Overall among the cultivars, Resal, Alex, Elite, Laser and Dr Baumans showed more consistency in terms of leaf gaseous exchange, biomass production and quality traits under planting date 1 and varying harvest stages. Investment in the year-round fodder flow establishment with high-quality forages is important in supporting sustainable sheep production. Forage legume-grass rotation systems are important not only for green fodder production of high crude protein, mineral and vitamin content throughout the year but also for enhanced soil fertility to reduce the nitrogen (N) fertilizer requirements. Accurate estimates of forage yields on the farm are required for fodder flow planning to ensure the seasonal distribution of fodder throughout the year. Objective three of the study was a no-tillage, short-term rotation experiment conducted to determine the growth and nutritive value of forage sorghum, planted after the winter annual forage legumes in combination with nitrogen application and to validate the performance of the APSIM-grain sorghum crop model in simulating forage sorghum growth and biomass production under different N rates. The treatments were planting date (January and February) and N source from inorganic N fertilizer (0 kg N ha-1, 60 kg N ha-1, 120 kg N ha-1, 180 kg N ha-1) and forage legume N residues (Alex, Capello, Dr Baumans, Elite, Hanka, Laser, Linkarus, Opolska, Resal and Timok) arranged in a randomized complete block design with four replicates. The findings of this study showed a significant response of forage sorghum growth and nutritive value to planting date. Delayed planting reduced plant height (11%), stem diameter (18%), LAI (6.7%), chlorophyll content (18%), NDVI (2.5%), photosynthetic rate (38%) and biomass production (8%). Delayed planting further reduced crude protein, acid detergent fiber and N yield. Nitrogen source from inorganic N at 60 kg N ha-1, 120 kg N ha-1, 180 kg N ha-1 and residual N from annual clover and vetch cultivars had a significant effect on morphological, physiological, yield and nutritive value parameters of forage sorghum. xxiii Generally, legume N residue effects on all the studied parameters of forage sorghum were similar to the inorganic N fertilizer of 60 kg N ha-1. However, the effects differed widely according to the species and cultivar of the legume. Resal, Laser, Elite Capello and Dr Baumans N residue consistently showed greater effects than other legume residues. They consistently outperformed inorganic 60 kg N ha-1 on the most measured parameters. The results confirm that annual clover-forage sorghum and vetch-forage sorghum rotation have huge potential to reduce the cost and negative environmental effects associated with inorganic N use in forage prediction systems. Regarding the evaluation of the potential of the APSIM grain legume model to simulate forage legume DM and plant height, in general, the model performed well and accurately in predicting the shoot dry matter accumulation and plant height under 0 kg N ha-1, 60 kg N ha-1 and 120 kg N ha-1. However, it underestimated both these parameters at 180 kg N ha-1 implying that the application of N up to 180 kg N ha-1 is not necessary. APSIM-grain module was able to accurately predict forage biomass production under N rates up to 120 kg N ha-1 and it is therefore considered reliable to support the N nutrition in the forage sorghum fodder production systems. / University of Limpopo, research office under the UCDP program and National Research Foundation-Thuthuka