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Submitted by (lucia.rodrigues@ufrpe.br) on 2016-12-22T13:48:31Z No. of bitstreams: 1 Marisangela Viana Barbosa.pdf: 782275 bytes, checksum: e0f60df2d84c34d378476085357848db (MD5) / Made available in DSpace on 2016-12-22T13:48:32Z (GMT). No. of bitstreams: 1 Marisangela Viana Barbosa.pdf: 782275 bytes, checksum: e0f60df2d84c34d378476085357848db (MD5) Previous issue date: 2013-02-28 / The use of agroforestry systems (SAF’s) has been an alternative to reduce environmental impacts and assist in the recovery of degraded areas. In this context, the aim of this study was to evaluate the effect of inoculation with rhizobia strains and arbuscular mycorrhizal fungi associated with legume trees intercropped with cowpea [Vigna unguiculata (L.) Walp] in SAF's. Seedling production was carried out in the greenhouse of UFRPE / UAST. Using seeds of leucaena (Leucaena leucocephala (Lam.) de Wit) and mimosa (Mimosa caesalpiniifolia Benth.). The seeds were disinfected and inoculated with strains of native rhizobia (S1LRJ and S1003) and recommended by EMBRAPA (Semia 6069 and BR 3405) for leucaena and mimosa respectively, sown in containers with soil. After 100 days of emergency were planted in an experimental area of IFPE, Campus Belo Jardim, PE. The plot was composed of eight trees with spacing of 4.0 x 2.5 m, half inoculated with Gigaspora margarita. The experimental design was in randomized block (DBC) in factorial 2x2x4(with and without mycorrhiza, native and recommended rhizobia, and four times of assessment) with 3 blocks in split plot, each species being assessed separately. Evaluations were performed at implantation, at 60, 120 and 180 days by determining: plant height (AP), stem diameter of plants (DC) and the ratio of the height and diameter (RAPDC). At 60 days, was planted cowpea (Vigna unguiculata (L.) Walp.) Cultivar IPA 206, inoculated with strain (BR 3267) at a spacing of 0.5 x 0.5 m. Assessing the effect of different treatments on beans in DBC with factorial 4x2x2 (two trees with native and recommended rhizobia, with and without mycorrhiza and with and without rhizobia strains to cowpea) in split split plot. Determined shoot dry mass (MSPA), yield (kg ha-1), shoot total N, soil microbial biomass (BMS) and organic carbon. Data were subjected to analysis of variance and means were compared by Tukey test at 5% probability. Was observed highest developing in mimosa seedlings, with no isolated effect of the treatments, occurring interaction to G. margarita and Rhizobium S1003. There wasno influence of treatments for yield, total N and MSPA of cowpea and soil organic C and BMS. This study shows the importance of understanding the interactions micro-organism/plant to optimize the application of biotechnology in crop production. / A utilização de sistemas agroflorestais (SAFs), tem sido uma alternativa para reduzir os impactos ambientais e auxiliar na recuperação de áreas degradadas. Neste contexto, o objetivo deste estudo foi avaliar o efeito da inoculação de estirpes de rizóbios e fungos micorrizicos arbusculares associados a leguminosas arbóreas consorciadas com o feijão caupi [Vigna unguiculata (L.) Walp] em SAF’s. A produção de mudas foi realizada no viveiro da UFRPE/UAST. Utilizando sementes de leucena (Leucaena leucocephala (Lam.) de Wit) e sabiá (Mimosa caesalpiniifolia Benth.). As sementes foram desinfetadas e inoculadas com estirpes de rizóbios nativos (S1LRJ e S1003) e recomendados pela EMBRAPA (Semia 6069 e BR 3405) para leucena e sabiá respectivamente, semeadas em recipientes com solo. Após 100 dias de emergência foram plantadas em uma área experimental do IFPE, Campus de Belo Jardim, PE. A parcela foi composta por 8 arbóreas com espaçamento de 4,0 x 2,5 m, metade inoculada com Gigaspora margarita. O delineamento foi em blocos casualisados (DBC) em fatorial 2x2x4 (com e sem micorriza, rizóbios nativos e recomendados, e quatro épocas de avaliação) 3 blocos, em parcelas subdivididas, sendo avaliada cada espécie isoladamente. As avaliações foram realizadas na implantação, aos 60, 120 e 180 dias determinando: altura de planta (AP), diâmetro do colo das plantas (DC) e a relação da altura a planta pelo diâmetro RAPDC. Aos 60 dias, foi plantado o caupi (Vigna unguiculata (L.) Walp.) cultivar IPA 206, inoculada com a estirpe (BR 3267) em um espaçamento de 0,5 x 0,5 m. Avaliando o efeito dos diferentes tratamentos sobre o feijão em DBC com fatorial 4x2x2 (duas arbóreas, com e sem micorriza e com e sem estirpes de rizóbios) em parcela subsudivididas. Determinou-se a massa seca da parte aérea (MSPA), produtividade (Kg ha-1), N total da parte aérea, biomassa microbiana do solo (BMS) e carbono orgânico. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% probabilidade. Foi observado um maior desenvolvimento para as mudas de sabiá, não havendo efeito isolado dos tratamentos, observando-se interação para G. margarita e rizóbio S1003. Não houve influência dos tratamentos para produtividade, N total e MSPA do caupi e para o solo C orgânico e BMS. Este estudo mostra a importância do conhecimento das interações micro-organismo/planta, para otimizar a aplicação da biotecnologia na produção vegetal.

Hedgerows of the fodder tree legume Leucaena leucocephala (Lam.) de Wit ssp. glabrata (Rose Zárate) (leucaena) planted with companion grass (leucaena-grass pasture) form a productive, profitable and sustainable tropical pasture in northern Australia. Leucaena is renowned for its longevity (>30 years) and productivity under regular grazing, and this is a key factor in its profitability. To-date graziers and researchers have not been concerned about the sustainability of commercial leucaena-grass pastures, which are rarely fertilized. However, nutrient depletion could be expected after many years of nutrient removal under heavy grazing without replenishment, even on soils of moderate initial fertility. This study investigated the long-term productivity of leucaena-grass pastures in relation to nutrient depletion in Queensland. Experimental trials were conducted at 3 research stations and 6 commercial cattle properties. Prior to conducting field trials, a postal survey of leucaena growers ascertained perceived changes in leucaena, grass and livestock productivity over time. Physical and management factors influencing long-term pasture productivity were also explored. Graziers reported that leucaena productivity had declined in 58% of aging pastures. Lower livestock productivity was associated with declining leucaena growth, even though grass growth remained vigorous. Leucaena growth decline was more frequent on soil types of marginal initial fertility. Maintenance fertilizer was not applied to most (98%) leucaena pastures surveyed despite significant amounts of nutrient removal, particularly phosphorus (P) and sulphur (S), occurring over prolonged periods of moderate to high grazing pressure. It was predicted that under current management practices large areas of commercial leucaena pasture will be affected by soil nutrient depletion over the next 10 years. The effect of age of leucaena plants on pasture productivity was investigated in pastures aged from 8 to 38 years. Leucaena growth, expressed as rainfall use efficiency (RUE), declined with age (from 4.0 to 1.9 kg total dry matter (DM)/ha/mm), as did leaf nitrogen (N), P and S concentrations. Leucaena productivity decline was attributed to P and S deficiency restricting growth and symbiotic dinitrogen (N2) fixation. Composition of interrow grass changed from native grass dominance before leucaena establishment to green panic (Panicum maximum var. trichoglume) dominance in the aging leucaena pastures, particularly adjacent to leucaena hedgerows. This was attributed to increased soil Navailability. Leucaena and grass roots were concentrated in the topsoil; however, leucaena roots did extend beyond 1 m depth while grass roots did not. Changes in topsoil organic carbon (OC) and total nitrogen (TN) resulting from the planting of leucaena hedgerows into native grass pastures and previously cropped soils were studied. Topsoil OC and TN contents increased significantly under leucaena pasture (OC from 81-290 kg/ha/year and TN from 12-24 kg/ha/yr). Since TN and OC showed similar trends, there was no significant effect on carbon:N ratios. Leucaena contributed to soil OC both directly via plant part decomposition, and indirectly, via enhanced grass growth in the inter-row. Lower topsoil OC accumulation rates (81 kg/ha/yr) were observed in the older leucaena-grass pastures related to the decline in yield and vigour of leucaena in these aging pastures. The amount of carbon dioxide equivalent (CO2-e) accumulated in soil OC in productive leucaena-grass pasture was estimated to be higher than the amount of CO2-e emitted in methane from beef production from these pastures, thus positively impacting on their greenhouse gas balance. Leucaena responses to P and/or S applications were evaluated in a 30 year-old leucaenagrass pasture. Leucaena RUE and symbiotic N2 fixation were restricted by S deficiency. Sulfur concentration in leaf tissue and high N:S ratio were useful indicators of S deficiency. Although leucaena growth and its nutritional status were little affected by P application, symbiotic N2 fixation did respond significantly to P application. Leucaena and grass responses to fertiliser applications were further evaluated at a variety of soil types and environments on 8 sites in Queensland. Increased leucaena RUE (from 3.1 to 4.6 kg total DM/ha/mm) and enhanced nutritional status at most sites showed that leucaena plants were restricted by P and/or S deficiency. The major factors contributing to the P and S deficiencies were: a) inherent low soil P and/or S fertility, b) nutrient removal by cropping and grazing, c) shallow soils, d) acid soils, and e) grass competition for available water and nutrients. Inter-row cultivation (with or without fertiliser) had little effect on leucaena growth but significantly increased grass RUE (from 4.7 to 7.0 kg total DM/ha/mm) at some sites probably due to enhanced mineralization of N. Leaf P and S concentrations were not reliable indicators of deficiencies of these nutrients, possibly due to inadequate leaf sampling conditions. The effects of ambient temperature, water stress and phenological development of plant on nutrient concentrations in leucaena leaf was investigated to determine whether leaf tissueanalysis can reliably predict nutrient deficiencies. The youngest fully expanded leaf (YFEL) was established as the most appropriate leaf tissue for predicting nutritional status of leucaena plants since the YFEL: (a) was an easily identifiable tissue in which nutrient shifts were at a minimum; (b) provided information for readily mobile (N, P and potassium) and variably mobile (S, copper and zinc) nutrients, thus simplifying leaf collection; and (c) facilitated comparison of data from leaves of similar physiological age in different growing conditions and sites. Nutrient concentrations in YFEL were significantly influenced by water stress and phenological stage of plant development (particularly flowering and pod filling) through the mechanism of rate of leaf appearance. Chronological age of the YFEL, an indicator of leaf appearance, varied from 12 to >70 days depending upon plant phenological stage, being >140 days under prolonged water stress. It was found that nutrient concentrations in leucaena YFEL can only be interpreted against critical concentrations if plants are actively growing (October-April) in a vegetative stage and YFEL are <20 days old. This will occur if there is no water stress for ≥28 days prior to sampling. A close correlation existed between chronological age of YFEL and leaf calcium (Ca) concentration. Calcium concentration could be used to assess the age of YFEL and thereby determine the suitability of tissue samples for nutrient analysis and interpretation. Leaves with Ca concentrations >0.7% DM should be discarded as they are likely to be too old (>20 days). The research program has identified that leucaena established on non-alluvial soils need to be provided with regular maintenance P and S fertiliser to promote symbiotic N2 fixation and to maintain high RUE. At present, many leucaena pastures are likely to be suffering undiagnosed nutrient deficiencies that will be limiting pasture and animal productivity and enterprise profitability. Youngest fully expanded leaf analysis can be used as a predictive tool to diagnose nutrient deficiencies provided the recommended protocol is followed. Further investigation is required to: a) assess the duration of responses to applied fertiliser to determine frequency of application; b) investigate the rate of maintenance fertiliser P and S that has to be applied to maintain leucaena symbiotic N2 fixation and RUE at a desired level to benefit both forage quality and quantity, and soil fertility; c) study methods of fertiliser placement for adequate and timely supply of nutrients, particularly P, to leucaena roots; and d) confirm the use of Ca concentration in YFEL as a predictor of optimum leaf age for the range of soils and areas where leucaena is grown.