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Para que o potencial de cultivares comumente usados como o Marandu {Brachiaria brizantha (Hochst. ex A. Rich.) RD Webster [syn. Urochloa brizantha (A. Rich.) Stapf]; CIAT 6297}, com alta produção como o Tifton 85 (Cynodon spp.), e recentemente lançados como o Mulato II (Convert HD 364®) (Brachiaria híbrida CIAT 36061) possa ser racionalmente e intensivamente explorado é necessário entender como as frequências de corte afetam as respostas produtivas, por meio de inferências fisiológicas. O objetivo foi avaliar e descrever o efeito de duas frequências (28 e 42 dias) sobre as características de análise de crescimento do Mulato II, Marandu, e Tifton 85, e características morfogênicas do Mulato II e Marandu. O experimento foi conduzido em Piracicaba, SP, o delineamento experimental foi de blocos completos casualizados, com quatro repetições. As respostas incluiram índice de área foliar (IAF), taxa de crescimento de cultura (TCC), taxa de crescimento relativo (TCR), taxa de assimilação líquida (TAL), razão de área foliar (RAF) e razão de peso foliar (RPF), filocrono, número de folhas vivas por perfilho (NFV), taxa de alongamento de folhas (TALF) e de colmos (TALC), taxa de aparecimento de folhas (TAPF), densidade populacional de perfilhos (DPP) e taxa de senescência de folhas (TSF). A TCC foi igual para o Mulato II e Tifton 85 mas a RPF foi maior para o Mulato II. O Tifton 85 com menor IAF residual apresentou altos valores de TAL e resultados semelhantes ao Mulato II de TCC. A TAPF e TALF foram maiores no Marandu do que no Mulato II. O filocrono foi maior no Mulato II comparado ao Marandu. Houve interação frequênca x ano para o filocrono, e aos 28 dias o menor filocrono foi no primeiro ano, e com 42 dias não houve diferença entre os dois anos. A TALF, TALC e TSF foram maiores com 42 dias. Houve interação frequência x ano e capim x frequência no NFV. Este foi maior no primeiro ano com 28 e 42 dias, e aos 42 dias nos dois anos. O NFV foi igual no Marandu e Mulato II com 28 dias e maior no Marandu com 42 dias. Tanto o Marandu quanto o Mulato II tiveram maior NFV com 42 dias. A TCC é similar no Mulato II e no Tifton 85, mas a RPF é maior no Mulato II. O Tifton 85 teve menor IAF residual, mas alta TAL e TCC similar ao Mulato II. O Mulato II e o Tifton 85 utilizaram mecanismos diferentes para alcançar a mesma TCC. 28 dias é melhor pois prioriza produção de folhas. Nas características morfogênicas, o Marandu é melhor pois apresentou maiores taxas de crescimento (TAPF, TALF ,NFV) e menor filocrono. Apesar do Marandu ser superior ao Mulato II isso não refletiu em maior acúmulo de forragem e valor nutritivo, devido à DPP ter sido maior no Mulato II. Houve maior TALC e TSF com 42 dias, portanto 28 dias é melhor para evitar altas TALC. Quando houver pluviosidade adequada é necessário a utilização de menor frequência (28 dias) para aumentar a eficiência de colheita da forragem. / For the potential of cultivars most commonly used as Marandu palisadegrass {Brachiaria brizantha (Hochst. ex A. Rich.) RD Webster [syn. Urochloa brizantha (A. Rich.) Stapf]; CIAT 6297}, with high forage production as Tifton 85 (Cynodon spp.), and grasses recently released as Mulato II (Convert HD 364®) (Brachiaria híbrid CIAT 36061) to be rationally and intensively explored it is necessary to understand how harvest frequency affects productive responses, under a physiological standpoint. The objective was to evaluate and describe the effect of harvest frequency on the growth characteristics of Mulato II, Marandu, and Tifton 85, as well as to study morphogenesis characteristics in Mulato II and Marandu. The experimental design was a randomized complete block with four replications. The trial was carried out in Piracicaba - SP. Response variables included leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and leaf weight ratio (LWR). In addition phyllocron, number of live leaves per tiller (NLL), stem (SER) and leaf elongation rate (LER), leaf appearance rate (LApR), tiller density population (TDP) and leaf senescence (LSR). Mulato II is a option to intensify and diversify pasture grasses in tropical areas due to its high LAI, CGR, LWR and LAR. CGR was similar between Mulato II and Tifton 85 but LWR was highest to Mulato II. On the other hand, Tifton 85 starts the lowest LAI but has high NAR and reaches the same CGR to Mulato II, showing also as good forage option. The LApR and LER were higher an Marandu than Mulato II. Phyllochron was higher in Mulato II compared to Marandu. There was an interaction harvest frequency x year to phyllochron, and with 28 days the lowest phyllochron was at first year, and with 42 days there was no difference between two years. The LER, SER and LSR were higher with 42 days of harvest frequency. There was interaction harvest frequencies x year and cultivars x harvest frequencies to NLL. This was higher in the first year with 28 and 42 days, and at 42 days in both years studied. NLL was equal in Marandu and Mulato II with 28 days and higher in Marandu with 42 days. Marandu and Mulato II had higher NLL with 42 days. CGR is similar in Mulato II and Tifton 85, but the LWR is highest in Mulato II. Tifton 85 had lowest residual LAI, but high NAR and CGR similar to Mulato II. Mulato II and Tifton 85 used different mechanisms to achieve the same CGR. 28 days prioritizes leaf production. In morphogenesis, Marandu is the best because it presented the highest growth rates (LApR, LER, NLL) and lowest phyllochron. Despite Marandu was better than Mulato II, it did not reflect in greater herbage accumulation and nutritive value, due greater TDP in Mulato II. There was highest SER and LSR with 42 days, so 28 days is best to avoid high SER. When there is adequate precipitation, lowest frequency (28 days) increase harvest efficiency.

The reemergence of Goss’s wilt of corn in the western Corn Belt in 2006, along with subsequent identification of the disease in 16 states, has led to renewed interest in the disease and its epidemiology. Goss’s wilt, caused by the bacterium Clavibacter nebraskensis, is currently the third-leading cause of yield loss in corn from diseases in the United States. Its impact is exacerbated by the fact that cultural control methods are the only current means for its control. The objectives of our research were to (1) determine the role that alternative hosts of the bacterium play in the disease cycle and epidemiology of Goss’s wilt, and (2) determine if postemergence herbicide use affects disease severity. Through a greenhouse experiment, we discovered three new weedy alternative hosts of the disease. In a series of field and greenhouse experiments, we found that C. nebraskensis can overwinter on alternative host and corn debris in Indiana. We found that C. nebraskensis did not become seed-borne in alternative hosts. In contrast to corn, no systemic infections were observed on alternative hosts, with the bacterium being restricted to inoculated leaf tissue. Using herbicides to control C. nebraskensis-infected weeds did not reduce the pathogenicity of the bacterium recovered from treated plants. The use of nicosulfuron, dicamba plus diflufenzopyr, and a 2X rate of glyphosate postemergence increased disease severity in one experiment, but postemergence herbicides did not influence disease severity in a second experiment. Corn yield was not affected. This indicates that herbicide use may play a role in the epidemiology of Goss’s wilt in some years, but ultimately corn yield is not affected. Our results demonstrate that the host range of C. nebraskensis is wider than previously thought, and that postemergence control of alternative hosts may not be sufficient in reducing inoculum levels. Our results suggest that failure to control alternative hosts could negate some of the benefits of crop rotation to reduce inoculum levels in a field, thus playing an important role in the epidemiology of Goss’s wilt. <br>

The thesis investigates the processes of the formation and functioning of Water Users Associations (WUAs) which have been implemented under the policy of Participatory Irrigation Management (PIM) in Maharashtra, Western India. The thesis explores (1) how social and economic hierarchies shape the process of participation in WUAs; (2) the roles played by the State and Non-Governmental Organisations in the process of participatory development; (3) the ways in which processes of neo-liberalisation have influenced water reforms in a developing country like India. The study draws on different critiques of neo-liberalism, and it explores theories of participation to provide a holistic understanding of PIM (Participatory Irrigation Management) reforms carried out in Maharashtra. The study uses a qualitative approach, based on ethnographic fieldwork carried out over twelve months at two Water Users Associations in a village in the Nashik district of Maharashtra. The study finds that processes of participation are complex, and characterized by the vested interests of the different actors involved in the process of the formation and functioning of WUAs in the village. The WUAs have been able to provide water to many farmers in the area. However, the policy has been unable to achieve much success in terms of resolving conflicts among farmers and enhancing the participation of small landholding and marginalized farmers in the WUAs. I found that the process of neo-liberalisation does not challenge or reform traditional institutions such as caste and gender, but rather that it uses them to entrench market reforms. The implementation of WUAs' policy in the wider neo-liberal context has increased the powers of the State and NGO intervention in the formulation and implementation of WUAs policy. Processes of WUAs' formation and functioning are significant examples of the ways in which neo-liberalisation is taking shape in India, including the commodification of water, and thereby, the reproduction of existing hierarchies and power imbalances. The study contributes towards developing an understanding of the wider processes of neo-liberal governance in the water sector.

This thesis examines how constitutional reforms relating to the right to water in Bolivia have affected water provision in peri-urban Cochabamba. This multi-sited ethnography explores how the right to water has framed reforms to the Bolivian water sector, how and why the right to water has been contested in Bolivia, the impact of reforms to the water sector on peri-urban water committees and emerging challenges and opportunities for sustainable water provision in peri-urban Bolivia. It demonstrates that despite the high profile role played by Bolivia in advancing the right to water at the international and national level, in practice the right to water continues to be a fairly nebulous concept. There is a disconnect between Bolivia's international stance on the human right to water and national reforms around the right to water. This thesis contends that the right to water is a banner under which the water sector has been reformed since the election of Evo Morales in 2006. Even though the constitution states that everyone has the right to water, in practice water often continues to be provided through community providers such as drinking water committees (DWCs), largely due to the failure of municipal water provision. Reforms and policy have focussed on (re)nationalising the sector and establishing new institutions to regulate and develop diverse water providers such as peri-urban DWCs. Through detailed ethnographic examination of peri-urban Cochabamba, the thesis demonstrates that activists and community-water providers in rural and peri-urban areas have contested reforms linked to the right to water. They have contended that reforms have the potential to undermine community water systems, and furthermore, that the state has failed to guarantee basic human rights and service provision. To date, the state and non-state initiatives to enhance the sustainability of DWCs have focussed on certain elements of sustainability, specifically protecting the aquifer and enhancing institutional sustainability of DWCs. By drawing on the experience and development of one DWC, this thesis also explores further elements that present challenges and opportunities to enhance sustainable water provision in peri-urban areas, namely building equitable access, and the reconciling of local power relations.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-02-15T12:44:24Z No. of bitstreams: 1 Jorge Serrao Pinto Filho.pdf: 1255280 bytes, checksum: b96b8cb8323e3c90862fc8d89ce64c78 (MD5) / Made available in DSpace on 2017-02-15T12:44:24Z (GMT). No. of bitstreams: 1 Jorge Serrao Pinto Filho.pdf: 1255280 bytes, checksum: b96b8cb8323e3c90862fc8d89ce64c78 (MD5) Previous issue date: 2016-02-26 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The objective was to evaluate the carcass characteristics and components non-carcass of sheep kept on native pasture semiarid region subjected to different offer levels forage (2.0, 2.5, 3.0, 3.5 kg DM / kg BW). The pasture was made up of Caatinga, enriched with grass búffel (Cenchrus ciliares L. cv Biloela) and grass corrente (Urochloa mosambicensis (Hack.) Dandy.), with the predominance of mainly native species such as mororó (Bauhinia cheilantha (Bong.) Steud.) and the Feijão bravo (Capparis flexuosa L.). The grazing season was held at two years (2013 and 2014) with a duration of 39 and 84 days, respectively, being animals slaughtered above after these periods. It was made skinning and gutting and then it was obtained the absolute weights not carcass components, the empty body weight (EBW), hot carcass weights (HCW). After the carcass were placed in a cold chamber at 4 ° C for 24 hours. The still entire carcass were evaluated its morphometry. In the left half carcass It was made the cuts commercials shoulder, neck, hand saw, rib, loin and ham. Was used a completely randomized designing in split plot. Occurred quadratic effect (P<0,05) between herbage allowance levels of the consumption of dry matter (CDM), the consumption of organic matter (COM), the consumption of neutral detergent fiber (CNDF), the consumption of acid detergent insoluble protein (CADIP), digestibility of dry matter (DDM), the total weight gain, the average daily gain weight, body weight at slaughter (BWS), the the empty body weight (EBW), hot carcass weight (HCW), the cold carcass weight (CCW) and cut loin showing better values between the average level of 2.83 (kg DM / kg BW). The herbage allowance levels of (kg DM / kg BW) do not alter the characteristics of the weight of components not sheep carcasses kept on native pasture Semiarid. / Objetivou-se avaliar as características de carcaça e os componentes não-carcaça de ovinos mantidos em pasto nativo do Semiárido submetidos a diferentes níveis de oferta de forragem (2,0; 2,5; 3,0; 3,5 kg MS/ kg PC). O pasto era constituído de Caatinga, enriquecida com capim búffel (Cenchrus ciliares L. cv Biloela) e capim corrente (Urochloa mosambicensis (Hack.) Dandy.), com o predomínio principalmente das espécies nativas como o mororó (Bauhinia cheilantha (Bong.) Steud.) e o Feijão bravo (Capparis flexuosa L.). A estação de pastejo foi realizada em dois anos (2013 e 2014) com duração de 39 e 84 dias, respectivamente, sendo os animais abatidos logo após estes períodos. Foi feito a esfola e evisceração, em seguida foi obtido os pesos absolutos dos componentes não carcaça, o peso corporal vazio (PCVZ), pesos de carcaça quente (PCQ). Após as carcaça foram colocadas em um câmara fria a 4 ºC por 24 horas. As carcaça ainda inteiras foram avaliadas sua morfometria. Na meia carcaça esquerda foi feito os cortes comerciais paleta, pescoço, serrote, costela, lombo e pernil. Utilizou-se o desenho experimental interiamente casualizado em parcelas subdivididas. Ocorreu efeito quadrático (P<0,05) entre os níveis de oferta de forragem sobre o consumo de matéria seca (CMS), o consumo de matéria orgânica (CMO), o consumo de fibra em detergente neutro (CFDN), o consumo de proteína insolúvel em detergente ácido (CPIDA), a disgestibilidade da matéria seca (DMS), o ganho de peso total, o ganho de peso médio diário, o peso corporal ao abate (PCA), o peso corporal vazio (PCVZ), o peso de carcaça quente (PCQ), o peso de carcaça fria (PCF) e o corte lombo apresentando melhores valores entre o nível médio de 2,83 (kg de MS/ kg de PC). Os níveis de oferta de forragem (kg de MS/ kg de PC) não alteraram nas características dos componentes não carcaça de ovinos mantidos em pasto nativo do Semiárido.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-02-20T13:27:48Z No. of bitstreams: 1 Helton Gregory Santos Arcanjo.pdf: 4191162 bytes, checksum: 452240cd8f0bf89315fa2e6185a06c0d (MD5) / Made available in DSpace on 2017-02-20T13:27:48Z (GMT). No. of bitstreams: 1 Helton Gregory Santos Arcanjo.pdf: 4191162 bytes, checksum: 452240cd8f0bf89315fa2e6185a06c0d (MD5) Previous issue date: 2014-02-26 / Considering all the knowledge about the variation of native grasses quality and quantity is dependent on the time of year, plus the unknowing and inability in determine the dry matter intake of goats, it sought with this research estimate the pasture intake by these animals. The experiment was conducted to evaluate the external markers chromium oxide (Cr2O3), titanium dioxide (TiO2) and insoluble lignin purified and enriched (LIPE®), such as internal markers: indigestible dry matter (MSi), neutral detergent fiber indigestible (NDFi) and acid detergent fiber indigestible (ADFi) to estimate the dry matter apparent digestibility, fecal dry matter production and estimated dry matter intake by goats kept on native pasture in the semiarid region. It worked with 20 castred males without defined breed, with average body weight of 26 ± 8.4 kg, when five of all were rumen fistulated and 15 did not. The field activity lasted 30 days, 15 days to adapt the animals and the other 15 to providing indicators and colect samples (feces and extrusa). The statistic experimental design was completely randomized (CRD), and the results submitted to the Tukey test at 5% for comparison of means. The internal markers were submitted to descriptive analysis with in vitro digestibility of dry matter (DM) through regression analysis. And then, the results presented that estimates of dry matter intake considering IVDMD, through internal markers were more precise and accurate when used MSi and NDFi, and the opposite being observed for ADFi and the equation. Although about the internal markers, IVDMD and equations were used to estimate the dry matter intake, but significant differences (P<0.05) were observed for the equations while the estimates fecal output through external markers differed significantly (P>0.05) from the result of the total collection. TiO2, Cr2O3 and LIPE ® markers presented statistically different estimate (P>0.05) from total collection, as well as the TiO2 from others markers. LIPE® and Cr2O3 underestimated the fecal output. Regarding the time and method of collection no statistical differences (P>0.05), for any marker and/or method. Therefore, even on native grazing, internal markers proved to be a relevant tool in obtaining data on digestibility and dry matter intake. Can thus supply management supplementation for goats when grazing in rangeland. / Com o conhecimento da oscilação da qualidade e quantidade do pasto nativo em função da época do ano, aliado ao desconhecimento e impossibilidade de determinar o consumo de matéria seca de caprinos, buscou-se com esse experimento estimar o consumo a pasto por esses animais. O experimento foi conduzido com o objetivo de avaliar os indicadores externos óxido de cromo (Cr2O3), dióxido de titânio (TiO2) e Lignina insolúvel purificada e enriquecida (LIPE®), como os internos matéria seca indigestível (MSi), fibra em detergente neutro indigestível (FDNi) e fibra em detergente ácido indigestível (FDAi) para estimativa da digestibilidade aparente da matéria seca, produção de matéria seca fecal e estimativa do consumo de matéria seca por caprinos mantidos em pasto nativo no semiárido. Foram utilizados 20 animais, machos, sem padrão racial definido, castrados, com peso corporal médio de 26±8,4 kg, sendo cinco animais fistulados no rúmen e 15 não fistulados. O experimento teve duração de 30 dias, 15 destinados à adaptação e 15 ao fornecimento dos indicadores e das coletas (fezes e extrusa). O delineamento utilizado foi o inteiramente casualizado (DIC), e os resultados submetidos ao teste de Tukey a 5% para comparação de médias. Os indicadores internos foram submetidos à análise descritiva com a digestibilidade in vitro da matéria seca (DIVMS) por meio da análise de regressão. De posse dos resultados, as estimativas do consumo de matéria seca considerando a DIVMS, por meio dos indicadores internos foram mais acuradas e precisas quando se fez uso da MSi e FDNi, não sendo observado o mesmo para a FDAi e pela equação. Ainda os indicadores internos, a DIVMS e as equações foram utilizados para a estimativa do consumo de matéria seca, porém diferenças significativas (P<0,05) foram observadas para as equações Já as estimativas da produção fecal por meio dos indicadores externos diferiram significativamente (P>0,05) do resultado da coleta total. Os indicadores TiO2, Cr2O3 e LIPE® apresentaram estimativa diferente estatisticamente (P>0,05) da coleta total, assim como o TiO2 dos outros indicadores. O LIPE® e o Cr2O3 subestimaram a produção fecal. Em relação aos horários e métodos de coleta, não foram observadas diferenças estatísticas (P>0,05), para nenhum indicador e/ou método utilizado. Portanto, mesmo em condições de pastejo nativo os indicadores internos mostraram ser uma ferramenta relevante na obtenção de dados sobre digestibilidade e consumo de matéria seca. Podendo assim, estabelecer planos de suplementação para caprinos quando em pastejo em pasto nativo.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-03-14T13:22:51Z No. of bitstreams: 1 Paulo Ferreira da Silva.pdf: 1871633 bytes, checksum: e99149f8fc75908f1d9ee5e36ea3b553 (MD5) / Made available in DSpace on 2017-03-14T13:22:51Z (GMT). No. of bitstreams: 1 Paulo Ferreira da Silva.pdf: 1871633 bytes, checksum: e99149f8fc75908f1d9ee5e36ea3b553 (MD5) Previous issue date: 2015-07-20 / The natural vegetation of Caatinga is relatively well adapted and tolerant to drought and to high temperatures. It is known that forest conversions to pasture and/or crop cultivation are human interventions, which affect energy exchanges, water and carbon between land surface and the atmosphere. However, up to the present moment, there is no study measuring these fluxes in the caatinga and pastures areas in the Brazilian semiarid lands. Thus, this paper aimed at determining the fluxes of energy, H2O and CO2 in areas of caatinga and pastures, as well as at analyzing the seasonal variability patterns of these fluxes. The land activities were carried out in two areas, one of them located on the Buenos Aires farm (7° 59’ 31’’ S and 38° 17’ 59’’ O), and the other located on the Lagoinha farm (07° 56’ 50,4’’ S and 38° 23’ 29’’ O), cultivated with pasture of grass chain (Urochloa mosambicensis), both properties located in the city of Serra Talhada, state of Pernambuco, Brazil. In order to determine the fluxes of energy, H2O and CO2, a methodology of correlation of swirls was adopted, by means of micrometeorological towers, installed in the center of each experimental area. Along with the index of foliar area, we have also measured the aboveground phytomass of both the pasture and the caatinga herbaceous vegetation, as well as water storage in the soil, by means of TDR sensors. On the basis of the results, it has been found that the maximum production of dry pasture mass was in the order of 2,208 kg ha-1 and annual average of 832 kg ha-1. On the other hand, the caatinga dry mass was in the order of 2,559 kg ha-1 and the annual average was 626 kg ha-1. Water storage in the soil (0-40 cm) of pasture was 29% greater than the one of the caatinga. This fact was possibly attributed to the interception of rain by the caatinga canopy. In relation the fluxes of energy, radiation balance (Rb) was used mainly as sensitive flow of heat (H), with 51% in the pasture and 47% in the caatinga. The fraction of Rb used as flow of latent heat (LE) was of 23% in the pasture and 32% in the caatinga. In relation to the evapotranspiration, the caatinga had total values (523 mm) and average values (1,4 mm d-1) greater than the pasture (389 mm and 1,1 mm d-1), possibly due to the greater depth of its radicular system. During the experimental period, the fluxes of daily average CO2 were ˗ 0,91 and ˗ 0,68 μmol m-2 s-1 for the caatinga and the pasture, respectively. Not only during the rainy season but also the dry season, the vegetation acted as atmospheric CO2 sink. The caatinga was more efficient than the pasture, sequestrating in average 14,6 kg of C ha-1 d-1, during the rainy season and 4,3 kg of C ha-1 d-1, in the dry season, while the pasture sequestrated 11,7 kg of C ha-1 d-1, in the rainy season and 2,5 kg of C ha-1 d-1, in the dry season. The caatinga has proved more efficient than the pasture in using soil water (greater ET) and in sequestrating atmospheric CO2. / A vegetação natural da Caatinga é relativamente bem adaptada e tolerante à seca e a altas temperaturas. Sabe-se que a conversão de florestas em pastagens e/ou cultivo de lavouras são intervenções humanas que afetam as trocas de energia, água e carbono entre a superfície da terra e a atmosfera. No entanto, até o momento não se tem nenhum estudo medindo esses fluxos em áreas de caatinga e de pastagens no semiárido brasileiro. Desse modo, este trabalho teve como objetivo determinar os fluxos de energia, H2O e CO2 em áreas de caatinga e de pastagens, além de analisar os padrões de variabilidade sazonal desses fluxos. A s atividades de campo foram realizadas em duas áreas, sendo uma localizada na Fazenda Buenos Aires (7º 59’ 31” S e 38º 17’ 59” O) e a outra localizada na Fazenda Lagoinha (07° 56’ 50,4”S e 38° 23’ 29” O), cultivada com a pastagem capim corrente (Urochloa mosambicensis), ambas propriedades localizadas no Município de Serra Talhada PE. Para a determinação dos fluxos de energia, H2O e CO2 foi usada a metodologia da correlação dos turbilhões, por meio de torres micrometeorológicas instaladas no centro de cada área experimental. Foram medidos o índice de área foliar e a biomassa áerea da pastagem e da vegetação herbácea da caatinga e o armazenamento de água no solo, por meio de sensores TDR. Dos resultados, verificou-se que a produção máxima de massa seca da pastagem foi de 2.208 kg ha-1 e média anual de 832 kg ha-1, já a massa seca máxima da caatinga foi de 2.559 kg ha-1 e a média anual de 626 kg ha-1. O armazenamento de água no solo (0-40 cm) da pastagem foi 29% maior que da caatinga, possivelmente devido a interceptação da chuva pelo dossel da caatinga. Com relação aos fluxos de energia, o saldo de radiação (Rn) foi utilizado principalmente como fluxo de calor sensível (H), com 51% na pastagem e 47% na caatinga. A fração do Rn usada como fluxo de calor latente (LE) foi de 23% na pastagem e 32% na caatinga. Com relação a evapotranspiração, a caatinga teve valores totais (523 mm) e médios (1,4 mm d-1) maiores que a pastagem (389 mm e 1,1 mm d-1), possivelmente, devido a maior profundidade de seu sistema radicular. Durante o período experimental os fluxos de CO2 médios diários foram de -0,91 e -0,68 mol m-2 s-1 para a caatinga e a pastagem, respectivamente. Tanto na estação chuvosa quanto na estação seca, ambas as vegetações atuaram como sumidouro de CO2 atmosférico. A caatinga foi mais eficiente que a pastagem, sequestrando em média 14,6 kg de C ha-1 d-1, na estação chuvosa e 4,3 kg de C ha-1 d-1, na estação seca; enquanto a pastagem sequestrou 11,7 kg de C ha-1 d-1, na estação chuvosa e 2,5 kg de C ha-1 d-1, na estação seca. A caatinga demonstrou ser mais eficiente em usar a água do solo (maior ET) e sequestrar CO2 atmosférico que a pastagem.

A Amazônia brasileira apresenta grande importância no processo de ciclagem de carbono na atmosfera, pois representa uma significativa parcela das florestas tropicais remanescentes. Porém, nos últimos 50 anos a Amazônia Legal Brasileira passou por intenso processo de mudança no uso da terra, fato que ocasionou aumento do desflorestamento na região. No Estado do Pará, o município de Paragominas foi considerado um dos principais responsáveis pelo desflorestamento até o ano de 2007. Tal cenário foi modificado após iniciativas de instituições públicas e empreendedores ligados ao setor rural do município, que em ações conjuntas modificaram a produção agropecuária de Paragominas, implantando sistemas produtivos mais eficientes. Atualmente o município é reconhecido como pólo de produção agropecuário sustentável na Amazônia. Neste trabalho, objetivou-se avaliar a dinâmica do carbono no solo sob diferentes usos, em uma cronossequência, no município de Paragominas. O solo da área de estudo é classificado como LATOSSOLO AMARELO Distrófico de textura argilosa. A pesquisa foi realizada na Fazenda Vitória, Paragominas - PA, onde foram avaliadas duas cronossequências distintas: (i) floresta natural (em 1992)-floresta secundária (em 1992, com 16 anos)-floresta secundária (em 2013, com 37 anos); (ii) floresta natural-pastagem degradada (em 1992, com 23 anos)-pastagem em sistema agrossilvipastoril com plantio direto (em 2013, com 4 anos). Na segunda cronossequência também foram avaliados dados de um sistema lavoura-pecuária sem plantio direto conduzido na área entre 2005 e 2008. Foram avaliados os teores de carbono e nitrogênio, a relação C:N, a densidade do solo, os estoques de carbono e nitrogênio e a composição isotópica do solo das áreas de estudo, nas camadas 0-10, 10-20, 20-30, 30-40, 40-60, 60-80, 80-100 cm. Observou-se que a floresta secundária, em pousio há 37 anos, apresentou os maiores incrementos de C e N, sendo superior ao encontrado no solo sob floresta nativa. Na mesma área, mesmo após 44 anos de condução de pastagem na mesma área, mais de 70% do carbono ainda era oriundo de plantas de ciclo fotossintético do tipo C3. A reforma da pastagem proporcionou alterações positivas nas características edáficas, pois houve aumento no estoque de carbono no solo após o manejo em sistema agrossilvipastoril com plantio direto na palha, também foi observado diminuição da densidade do solo neste período. Conclui-se que a adoção de técnicas agropecuárias, que fazem uso racional dos recursos naturais, são viáveis e ambientalmente corretas, pois observou-se que após a mudança no manejo da área ocorreu aumento do estoque de carbono no solo, sendo este um indicador de sustentabilidade em agropecuária de baixa emissão de carbono no Brasil. / The Amazon region plays a great role in the process of cycling carbon within the atmosphere because it represents a significant portion of the remaining tropical forests. However, in the last 50 years, several municipalities have passed through changes in land-use management which led to a significant increase in deforestation. In 2007, the municipality of Paragominas was considered one of the main areas responsible of the deforestation of the State of Para, Brazil. After many joint actions of public institutions and agricultural entrepreneurs, Paragominas went through a process of change of the scenario in its agricultural production system. Today this municipality is recognized as a responsible agricultural and livestock production center in the Amazon. The aim of this study was to assess the dynamics of soil carbon under different land-use management systems in a chronosequence. The soil of the site is classified as a clayey oxisol (dystrophic yellow Latosols, in the Brazilian classification system). The study was carried out in the ranch \"Fazenda Vitoria\", where, two distinct chronosequences were assessed: (i) a native forest (in 1992) - a secondary forest (16 year old in 1992) - a secondary forest (37 year old in 2013); and (ii) a native forest converted to degraded pasture (23 year old in 1992) - pasture in a no-till silvopastoral agroforestry system (4 year old in 2013). In the second chronosequence, data from a no-till crop-livestosk system was also assessed, which was carried out from 2005 to 2008. Soil carbon and nitrogen contents and stocks, C:N ratio, soil bulk density and their isotopic composition were evaluated. The secondary forest fallowed for 37 years, had the highest increments of C and N contents, with higher values than those found in the soil under native forest. It was observed that after 44 years of grazing on the same area more than 70% of carbon was originated from C3-phostosynthetic type plants. Pasture recovery led to positive changes in soil properties, as an increase in carbon stock associated to the reduction of soil bulk density after the implement of the no-till silvopastoral management system. Decrease in soil bulk density was also observed in this period. According to the results obtained in the evaluated production unit, it was observed that the adoption of agricultural techniques that make a rational use of natural resources is sustainable and environmentally friendly. It was observed that the change in management of the area induced an increase in carbon storage in the soil, this being an indicator of agricultural sustainability in relation to low-carbon management.

Este estudo teve como objetivo avaliar e quantificar o efeito do sombreamento artificial proporcionado por diferentes áreas de sombra sobre a fisiologia e o comportamento de novilhas leiteiras, em ambiente de pastagens. A pesquisa foi realizada no período de fevereiro a abril de 2008. A área experimental foi dividida em 20 parcelas adjacentes com 84m² para os tratamentos 1, 2 e 3 e com 70m² para os tratamentos 4 e 5. Foram comparados a testemunha (tratamento 1, sem sombra) com 4 áreas de sombreamento por animal, tratamento 2 (com 1,5m²), tratamento 3 (3,0m²), tratamento 4 (5,0m²) e tratamento 5 (8,0m²), As dimensões dos abrigos foram 1,0m x 1,5m x 3,5m (largura, comprimento e altura) (1,5m² de sombra.animal-1), 1,5m x 2,0m x 3,5m (3,0m² de sombra.animal-1), 2,0m x 2,5m x 3,5m (5,0m² de sombra.animal-1) e 2,0m x 4,0m x 3,5m (8,0m² de sombra.animal-1), sem paredes laterais. Foram utilizadas 20 novilhas mestiças, 3/4 Jersey, ½ Holandesa e Jersey e Holandesas puras, com idade entre 12 e 25 meses e peso médio variando de 240 a 360kg, pareadas em função da uniformidade de peso e idade. As novilhas permaneciam em piquetes de Penissetum purpureum e complementação da dieta no cocho, durante a noite e após as 8:00 horas eram conduzidas para as parcelas. A Tgn foi registrada por um minidatalogger da marca LOGEN LS 8856 ALPAX. As variáveis meteorológicas foram obtidas no posto agrometeorológico da ESALQ/USP. Durante nove dias não consecutivos foram registradas FR e TS. As observações comportamentais foram realizadas em dias não consecutivos (nove dias) no período das 10:00 ás 16:00 horas pelo método focal. As condições ambientais em 66,7% do período da pesquisa foram em condição de estresse térmico para as novilhas. Os valores de FR e TS foram menores sob a maior área de sombra (P<0,05) e semelhantes entre os 1,5m², 3,5m² e 5,0m² (P>0,05). Houve correlação da Tgn com a FR e a TS. Não foram observadas alterações comportamentais entre os tratamentos, os animais ficaram sob as sombras nas horas mais quentes do dia, preferencialmente em pé, o comportamento seguiu os padrões conhecidos para bovinos. Para novilhas leiteiras a melhor área de sombreamento artificial é de 3m². / This study had as objective to evaluate and quantify the effect of artificial shading proportioned by different shadow areas under physiology and behavior of milk heifers, in pastures. Research was realized in the period from February to April, 2008. Experimental area was divided in 20 adjacent parcels with 84m2 to treatments 1, 2 and 3 and with 70m2 to treatments 4 and 5. Were compared witness (treatment 1, no shadow) with 4 shading areas per animal, treatment 2 (with 1,5 m²), treatment 3 (3,0 m²), treatment 4 (5,0 m²) and treatment 5 (8,0 m²). Shelters dimensions were 1,0m x 1,5m x 3,5m (width, length and height) (1,5m² of shade.animal-1), 1,5m x 2,0m x 3,5m (3,0m² of shade.animal-1), 2,0m x 2,5m x 3,5m (5,0m² of shade.animal-1) and 2,0m x 4,0m x 3,5m (8,0m² of shade.animal-1), without walls in the sides. Twenty crossbred heifers were used, 3/4 Jersey, ½ Holstein and pure Jersey and Holstein, with ages among 12 and 25 months and average weight varying from 240 to 360 kg, paired in function of weight and age uniformity. Heifers remained in Penissetum purpureum paddocks and had a diet complementation in the trough, during the period of night and after 8:00am they were conducted to the parcels. Tgn was registered by a minidatalogger from LOGEN LS 8856 ALPAX trend. Meteorological variables were obtained in the agrometeorological post from ESALQ/USP. During nine non consecutive days were registered FR and TS. Behavioral observations were realized in non consecutive days (nine days) in the period from 10:00am to 16:00pm by the focal method. 66,7% of environmental conditions in the period of research were in thermal stress conditions to the heifers. Values of FR and TS were minor under the major area of (P<0,05) and similar among 1,5m², 3,5m² and 5,0m² (P>0,05). There was a correlation of Tgn with FR and TS. Behavioral alterations among the treatments were not observed, animals stayed under the shadow in the hotter hours of the day, preferably on foot, behavior followed the known patters to bovine. For milk heifers the better of artificial shading area is 3m².