Master of Science / Department of Agronomy / Johanna A. Dille / Corn yield potential is limited by water deficit stress and limited soil nitrogen. Field and greenhouse experiments were conducted near Manhattan, KS in 2005 and 2006. The field experiment evaluated the influence of nitrogen (N) rate and increasing Palmer amaranth (PA) density grown alone and in competition with corn in two moisture environments. In 2006 the dryland environment was very drought stressed, while 2005 had more intermediate conditions. Weed-free corn yields were approximately half in dryland environments compared to the irrigated environment across years. Increasing PA density increased corn yield loss similarly in both 2005 environments and in 2006 dryland environment across all N rates. In the 2006 irrigated environment corn yield loss was increased by decreasing N rate and increasing PA density. Maximum predicted yield loss at high PA densities in both 2005 environments was 20-54% while in 2006 dryland environment, maximum yield loss was 95% and in the irrigated environment was 62%. In general, soil moisture environment was more critical than N rate or PA density when determining potential corn yield. In the greenhouse study a factorial arrangement of two irrigation methods and five crop-weed combinations (corn, PA, GF, corn/PA, and corn/GF) was established with two replications and three runs conducted. Two plants were grown in 25.4 cm diameter PVC pipe cut into 91.5 cm lengths. Irrigation application method included a surface and subsurface application. Plants were harvested at the V10 corn growth stage. No differences were detected between irrigation methods with respect to above- or below ground biomass production. Corn aboveground biomass was decreased by the presence of corn or PA but not GF. Below ground biomass information was presented as column totals because species could not be separated. There was no impact on root to shoot ratio, total below ground biomass, rooting depth, or root area across the crop-weed combinations except for the GF monoculture columns which were lower than all other crop-weed combinations. Future research needs to examine the light interception of corn and PA when grown at different N rates along with examining the influence of surface and subsurface irrigation practices on crop weed interactions and weed seed germination in a field setting.

Made available in DSpace on 2016-05-02T13:55:26Z (GMT). No. of bitstreams: 1 Rodrigo de Oliveira Cesarino.pdf: 260466 bytes, checksum: 275938861302541a4ebf1c00bb87b762 (MD5) Previous issue date: 2006-05-11 / Coordenacao de Aperfeicoamento de Pessoal de Nïvel Superior / Corn silage is an alternative forage to feed cattle of good energy value and if it goes well prepared it can present equivalent nutritious value to that existed in original green material This research was led with the objective of evaluating agronomic characteristics and bromatological in corn for silage fertilized in covering with liquid dejections of swine (LDS) The experiment was installed in a private property in the municipal district of Alfenas - MG Double hybrid corn was used Geneze 2005 and corn variety (Al-Band) The experimental disign was of blocks casualized with five treatments and four blocks The treatments were T1-witness without covering manuring T2-Nitrogen and Potassium at 30-00-20 350 kg/ha T3-50 m3 LSD/ha T4-100 m3 LSD/ha and T5-150 m3 LSD/ha The obtained results were submitted to the variance analysis with test Scott-Knott at the level of significance of 5% It was evaluated the heights of plants and of ears of corn fallen ill plants or broken percentage of dry matter and production of dry matter pH rude protein (PB) fiber in neutral detergent (FDN) fiber in acid detergent (FDA) digestibility in vitro of the matter evaporates (DIVMS) lignine and ashes The largest averages of plants height were observed in treatments that received manure covering and chemical fertilizer The largest averages of corn ear height happened in the treatments that received chemical fertilizer and 100 m3 LSD/ha The largest percentage of fallen ill plants and broken it was verified in variety Al-Band (4,0%) For the cultivate Geneze 2005 the production of dry matter was 15,5% superior than the variety Al-Band The largest production of dry matter was observed in the chemical treatment (14.913 Kg MS/ha) followed by the treatment of 150 m3 LSD/ha (13.719 kg MS/ha) The medium values of dry matter were influenced by the treatments presenting variations of 30,93% (witness) and 33,83% (chemical) The pH values presented a width of 3,72 (Al-Band) to 3,75 (Geneze 2005) differentiating statistically to each other It was observed in cultivating Geneze 2005 a larger value of PB in the chemical treatment (5,98%) followed by the other treatments In the treatments witness and 150 m3 DLS/ha the largest values of FDN were observed compared with the smallest value observed in the chemical fertilizer (53,87%) The largest percentage of FDA was observed in cultivating Geneze 2005 in relation to variety Al-Band It was observed that the treatment that received the chemical fertilizer in covering presented a larger coefficient of DIVMS (54,44%) The largest values of DIVMS were observed for to cultivate Geneze 2005 in the chemical treatment suggesting relation to the largest participation of grains however the values observed for to cultivate Al-Band didn't show statistical difference Chemical fertilizer treatment showed lower statistic level for lignin in both cultivates of corn In Ash percentage the witness treatment for both corn cultivates were higher than the treatments with LDS The manure covering with liquid dejections of swine above 100 m3/ha provided satisfactory productivities and of good nutritional value in corn growing for silage This way the liquid dejections of swine can be an alternative in the manuring in covering in the culture of the corn The hybrid Geneze 2005 presented the largest productivities when compared to variety Al-Band / Esta pesquisa foi conduzida em propriedade rural particular localizada no município de Alfenas - MG, no período experimental de novembro de 2004 a março de 2005 Objetivou-se obter informações sobre a influência da adubação com dejetos líquidos de suínos em cobertura sobre características agronômicas composição bromatológica e valor nutritivo de cultivares de milho utilizados para ensilagem O delineamento experimental foi em blocos casualizados com cinco tratamentos e quatro repetições Foram utilizados duas cultivares de milho comerciais Geneze 2005 e AL-Band Os tratamentos foram T1- testemunha sem adubação de cobertura T2-NK na fórmula 30-00-20, 350 kg/ha T3- 50 m3 DLS/ha T4-100 m3 DLS/ha e T5-150 m3 DLS/ha Os resultados obtidos foram submetidos à análise de variância e as médias separadas pelo teste Scott-Knott a 5% Avaliou-se os dados agronomicos altura de plantas e de espigas plantas acamadas ou quebradas porcentagem de matéria seca e produção de matéria seca Na silagem avaliou-se o pH proteína bruta (PB) fibra em detergente neutro (FDN) fibra em detregente ácido (FDA) digestibilidade in vitro da matéria seca (DIVMS) lignina e cinzas As maiores médias de altura de plantas foram observadas nos tratamentos que receberam tanto a adubação química quanto os que receberam cobertura com DLS As maiores médias de altura de espiga ocorreram nos tratamentos que receberam adubação química e 100 m3 DLS/ha A maior porcentagem de plantas acamadas e quebradas foi verificada para a cultivar AL-Band (4,0 %) Para a cultivar Geneze 2005 observou-se uma produção média de MS 15,5% superior a encontrada para a cultivar AL-Band A maior produtividade de matéria seca foi observada no tratamento químico (14.913 kg MS /ha) seguida do tratamento 150 m3 DLS/ha (13.719 kg MS/ha) Os teores médios de matéria seca foram influenciados pelos tratamentos apresentando variações de 30,93% (testemunha) e 33,83% (químico) Os valores de pH apresentaram uma amplitude de 3,72 (AL-Band) a 3,75 (Geneze 2005) diferenciando estatisticamente entre si Observou-se na cultivar Geneze 2005 um maior teor de PB no tratamento químico (5,98%) seguido dos demais tratamentos Nos tratamentos testemunha e 150 m3 DLS/ha foram observados os maiores valores de FDN comparado com o menor valor observado no químico (53,87%) A maior porcentagem de FDA foi observado na cultivar Geneze 2005 em relação a cultivar AL-Band Observou-se que o tratamento que recebeu a adubação química em cobertura apresentou um maior coeficiente de DIVMS (54,44%) Os maiores valores de DIVMS foram observados para a cultivar Geneze 2005 no tratamento químico podendo ser em função da maior participação de grãos porém os valores observado para a cultivar Al-Band não apresentaram diferenças estatísticas Com a adubação química observou-se menores valores médios de lignina em relação às adubações em cobertura com DLS para ambas as cultivares Os valores médios da porcentagem de cinzas foram estatisticamente superiores para ambas cultivares no tratamento testemunha A adubação em cobertura com dejetos líquidos de suínos acima de 100 m3/ha proporcionou produtividades satisfatórias e de bom valor nutritivo em milho para silagem Desta forma os dejetos líquidos de suínos podem ser uma alternativa na adubação em cobertura na cultura do milho

Recent trends to develop farmland into improved irrigated pastures raise questions regarding the profitability of creep supplementing terminal-sired calves on these production systems. This study was initiated to answer these questions. Two previously established adjacent sprinkler-irrigated plots were separated into 2 paddocks. One plot (3.4 ha) consisted of a monoculture of Seine tall fescue while the other plot (3.9 ha) consisted of a mixture of Seine tall fescue, AC Grazeland Alfalfa, and Norcen birdsfoot trefoil. The mixture of the second plot consisted of 50% tall fescue, 37.5% alfalfa, and 12.5% birdsfoot trefoil. Plots were designated as monoculture no-creep supplement (MONOC) (1.7 ha), monoculture with creep supplement (MONOS) (1.7 ha), mixed forage no-creep supplement (MIXC) (1.95 ha), and mixed forage with creep supplement (MIXS) (1.95 ha). Twenty-four spring calving cow-calf pairs were stratified into 4 groups based on calf body weight, sex, breed, dam body weight, dam BCS, and breed. Management-intensive grazing practices were implemented with cattle receiving a new allotment of forage at 0800 daily. Cattle grazed in a west-to-east direction across the pasture completing a grazing circuit every 24 to 30 d. Pasture forage production was estimated using a 0.163 m2 clip-plot. Forage production each period was highest for cattle grazing MIXS (4492 kg DM/ha) followed by MIXC (4116 kg DM/ha) (P=.58). Production from the MIX plot differed from MONO plot (P<.0001). Similar to MIX pasture production MONOC (3154 kg/ha) and MONS (3058 kg/ha) did not vary (P=.4324). Carrying capacity differed among all treatments. The highest carrying capacity was observed in the MIXS group with 3.37 pair/ha. The next highest carrying capacity was in the MIXC group at 3.05 pair/ha, which differed from MIXS (P=.0404). There was a difference between MIXC and MONOS (2.38 pair/ha) (P=.0051). The lowest carrying capacity was observed in the MONOC group (2.07 pair/ha), differing from MONOS (P=.0450). Calf end weight was highest for the MIXS group (343 kg) and differed from MONOC group (298 kg) (P=.0272); no other groups differed. Profitability did not follow pasture productivity completely. Due to high supplemental feed costs MIXC was the most profitable management strategy ($72.03 cow/yr) and was $137.50 cow/yr more profitable than the least profitable strategy, MONOS. Results from this study show that grass-legume mixtures are much more productive than grass monocultures under irrigation and management-intensive grazing of cow-calf pairs. In addition, on these forage resources the practice of supplying creep supplementation to high-growth, terminal calves is not economically profitable.

This investigation involved three tillage treatments, fall plowed (conventional) (moldboard IS-centimeter depth), fall chiseled (ripped) (25-centimeter depth), and no-tillage (zero tillage) replicated four times on an established alfalfa field. Rye was planted in the fall and harvested prior to planting the corn. Soil samples contained an average of 5.9 ppm phosphorus in the 0-30 centimeter soil layer, indicating the need for additional phosphorus. Within each tillage treatment, six rows received 11 kilograms/hectare phosphorus with the seed and 34 kilograms/hectare phosphorus side-dressed. Six rows received 45 kilograms/hectare phosphorus side-dressed, and four rows received 0 phosphorus. All 16 rows received 64 kilograms/hectare of nitrogen to ensure it was a non-limiting factor. Yields were significantly higher in every tillage plot that received phosphorus compared to the 0 kilograms phosphorus/hectare treatments in the plots. There was a trend of higher yields with the treatments of 11 kilograms/hectare + 34 kilograms/hectare side-dressed compared to the 45 kilograms/ hectare phosphorus side-dressed treatments. However, these were not significantly higher. The no-till plots yielded higher than the ripped or plowed in each tillage treatment. The differences between the no-till and ripped plots were not significant. However, the no-till plots yielded significantly higher than the plowed plot. The no-till 11 kilograms phosphorus + 34 kilograms phosphorus plots averaged 3.1 Megegrams/hectare higher silage yield than the plowed 11 kilograms phosphorus + 34 kilograms phosphorus plots and 2. 5 Megegrams/hectare higher in the 45 kilograms phosphorus side -dressed plots. Phosphorus uptake was measured by leaf sampling and found to be significantly higher in the no-till plots compared to the ripped and plowed plots. TON and protein were also determined, however, no significant differences existed between any tillage treatments. The rye was intended to be cut prior to planting for forage use in a dairy or cattle feeding program. Although the average dry weight was only 598 kilograms/hectare due mainly to late planting, this method has great economical potential.

The economic impact of reducing the amount of nitrate leached out of the root zone under irrigation in the arid West was examined. A general introduction into the nature of the problem and a review of the literature was provided in chapter I. In chapter ll the economic incentives of irrigation management were evaluated under the assumptions of both profit-maximizing and utility-maximizing (in reducing cost and effort expended in irrigation) decision-making criteria. The results indicate that there is a coincidence of interests of the farmer and the environment. Both behaviors result in less nitrate leaching than less profitable or less utilityproducing irrigating practices. In chapter lli the economic impact of reducing the amount of nitrate leached out of the root zone under irrigation with various nitrogen sources and application methods was examined. The economic incentives of nitrogen management were evaluated under the assumption of profit-maximizing behavior. The results indicate that there is a coincidence of interests for irrigators who respond to economic incentives and environmentalists who wish to reduce nitrate residuals in irrigation drainage and the groundwater. Profit-maximizing behavior results in less nitrate leaching than less profitable irrigating practices when salt balance is not a major concern.

No description available.

O presente trabalho tem, por objetivo, avaliar um sistema de produção de gramíneas irrigadas sob a dinâmica de corte rotacionado, simulando um sistema de irrigação tipo pivô central, com diferentes capacidades de armazenamento de água no solo. O manejo da irrigação foi realizado com base em tensiômetros instalados em uma parcela de referência do sistema. Realizou-se o trabalho em casa de vegetação, no Departamento de Irrigação da ESALQ/USP. Foram estudadas quatro cultivares de gramíneas: Capim Tanzânia e Capim Tifton 85 e Grama Santo Agostinho e Grama Esmeralda, sob seis estratégias de manejo da irrigação: M1, M2, M3, M4, M5, M6, sendo M3 a parcela de referência (umidade na capacidade de campo). Cada cultivar esteve submetido a quatro níveis de capacidade de água disponível (CAD), que variava em função da profundidade do solo no interior da caixa: 40, 30, 20 e 10 cm, sendo denominadas de S40, S30, S20 e S10. O solo utilizado no experimento foi classificado como Latossolo Vermelho Amarelo, textura franco arenosa. A adubação foi realizada para corrigir e manter o sistema. O experimento foi avaliado durante um período de 11 meses (de dezembro de 2006 a outubro de 2007), tendo a freqüência de corte, estabelecido em 30 dias, induzindo uma defasagem de corte de 5 dias entre os manejos estudados. A irrigação controlada pelo manejo M3 obteve consumo de água mínimo, quando o IAF era mínimo, ou seja, quando o bloco de controle era cortado, causava estresse hídrico nos outros blocos com índices de área foliar maior, tendo como hipótese inicial que estes apresentariam a maior produção. O potencial hídrico foliar foi medido antes do corte de cada manejo, sempre ao amanhecer, para garantir o equilíbrio hídrico solo-planta. Observou-se que a produção de matéria seca (MS)(kg.m-2) da parcela de controle M3 não foi diferenciada estatisticamente, contrariando a hipótese inicial do trabalho. A profundidade do solo não teve influência na altura média das gramíneas. O potencial hídrico foliar médio foi diferente para as quatro gramíneas, mas não se correlacionou significativamente (p>0,05) com a profundidade do solo. O capim Tifton 85 foi o que apresentou o maior potencial hídrico foliar. O capim Tifton 85, comparado ao Tanzânia, produziu de 7 a 27% a mais de proteína bruta (PB)(%) em relação à época de corte. A produção de MS(kg.m-2) foi maior para o capim Tanzânia, a única gramínea afetada pela profundidade de solo disponível. / The present work aims to evaluate a production system of irrigated grasses under rotary pasture system with center pivot irrigation simulation, considering four different total available water (TAW) in the soil profile, being the irrigation scheduling accomplished with tensiometers installed at a reference plot in the field. The work was carried out under greenhouse conditions at the Agricultural Department - Irrigation Sector at the University of Sao Paulo, Brazil. Four varieties of grasses were studied: Tanzania, Tifton 85, Saint Agostinho and Esmerald, under six strategies of irrigation scheduling: M1, M2, M3, M4, M5, M6, being M3 the reference plot (soil moisture maintain at field capacity). Each grass variety was submitted to four levels of soil depth inside the box: 40, 30, 20 and 10 cm, being denominated S40, S30, S20 and S10 TAW treatments. The soil was classified as Red Yellow Latossolo (silt sandy texture). Traditional fertilizer doses were applied for initial correction and maintenance of the system. The experiment was evaluated during a period of 11 months (December 2006 to October of 2007). Cutting frequency was established at 30 days, with a 5 days delay between irrigation scheduling treatments (M1 to M6). The M3 irrigation plot presented the minimum consumption of water when the leaf area index (LAI) was minimum. Just after cutting the reference plot the following treatments (M4 - M6) with higher LAI were submited to water stress conditions. Considering the initial hypothesis, M3 treatment would present the highest production. The water leaf potential was measured before cutting always at predawn to assure the water equilibrium at soil-plant system. It was observed that the production of dry matter (DM) at the reference plot M3 was not statistical differentiated, contradicting the initial hypothesis of the experiment. The average water leaf potential was different among grasses analysed, being not correlated significantly (p>0,05) with the soil depth (irrigation management considered the soil depth of each plot). Tifton 85 grass presented the highest water leaf potential. Tifton 85 grass compared to Tanzania produced 7 to 27% higher level of gross protein (GP). Tanzania grass presented the highest dry matter production (DM) and was the only grass affected by soil depth (TAW).

O ambiente de terras baixas no sul do Brasil é predominantemente explorado com a cultura do arroz irrigado. Baseado em um sistema agrícola pouco diversificado, é comum o uso sucessivo das mesmas áreas ano após ano, com práticas de manejo que envolvem o revolvimento do solo. Isto acarreta em prejuízos tais como a degradação do solo e recursos naturais, além de recorrente baixa rentabilidade da atividade. O cultivo de espécies forrageiras hibernais, associado com o não revolvimento do solo, pode trazer melhorias ao sistema produtivo, seja com seu uso como plantas de cobertura ou com o pastejo animal. O objetivo deste trabalho foi avaliar os benefícios e potencialidades que a utilização destas espécies podem proporcionar e, para tanto, dois estudos principais foram realizados. O primeiro, conduzido no município de Cachoeirinha, RS, avaliou o estado de agregação e o incremento do teor de carbono orgânico do solo, comparando cultivos sucessivos de arroz irrigado em um experimento de longa duração. Os tratamentos foram um sistema manejado na forma convencional, com revolvimento do solo, e outros três sob semeadura direta, com coberturas de: azevém, cornichão e vegetação espontânea. Os resultados indicaram que, na camada de 0 a 5 cm de profundidade, os tratamentos sob semeadura direta apresentaram maiores teores de carbono orgânico e agregação do que o convencional. Já na camada de 5 a 10 cm, para os agregados, o tratamento azevém se destacou em relação aos demais. O segundo estudo foi conduzido no município de Cristal, RS. Foram avaliadas a produção animal e de forragem durante três anos no período hibernal, em diferentes combinações de sistemas integrados de produção agropecuária (SIPA). Os cultivos estivais trataram-se de arroz irrigado, soja, capim sudão e campo de sucessão, enquanto as pastagens hibernais consistiram de azevém e consórcios desta espécie com trevo branco e cornichão. Os resultados confirmaram a adaptabilidade destas espécies forrageiras ao ambiente de terras baixas e demonstraram as potencialidades que a exploração pecuária possui, sendo necessários, porém, novos estudos para o melhor ajuste do manejo das áreas. Por fim, foi realizado um terceiro estudo, comparando a relação entre a massa de forragem e altura de pastos hibernais em SIPA conduzidos em terras altas com SIPA em terras baixas. A relação no ambiente de terras baixas é menor, corroborando a necessidade de maiores estudos neste ambiente, visto que as alturas ótimas preconizadas para o manejo do pasto se originam de estudos conduzidos em terras altas. / The lowland environment in Southern Brazil is predominantly explored with the irrigated rice crop. Based on a very low diversified system, in such environment is very common the successive use of the same areas year after year, with management practices that involve soil tillage. This leads to damages such as the degradation of soil and natural resources, in addition to recurrent profitability problems. The insertion of winter pasture species associated with the no-till, as cover crops or for animal grazing, may bring improvements to the system. The objective of the current work was to evaluate the benefits and potentialities that the utilization of such plants can provide. For this, two main studies were performed. The first, conducted in the Cachoeirinha County (Rio Grande do Sul State – RS), evaluated the soil aggregation status and its organic carbon content, by comparing successive irrigated rice croppings in a long-term experiment. The treatments consisted of one system under conventional soil tillage and three others under no-till, being the treatments the following cover crops: Italian ryegrass, birdsfoot trefoil and spontaneous vegetation. The results indicated that, in 0 to 5 cm soil layer, the treatments under no-till presented higher organic carbon contents and greater aggregation, as compared to the conventional system. In the 5 to 10 cm soil layer, the treatment with Italian ryegrass has its aggregation highlighted among the others. The second study was conducted in the Cristal County (RS). The animal and pasture production was evaluated during three years in the winter season, under different combinations of integrated crop-livestock systems (ICLS). The summer croppings were irrigated rice, soybean, Sudan grass and a succession field (native pasture), while the winter pastures consisted of Italian ryegrass and its mix with white clover and birdsfoot trefoil. The results confirmed the adaptability and potentiality of such pasture species and livestock exploration in the lowland environment. However, it is needed further studies for a better management adjustment of the areas. Finally, a third study was performed, comparing the relationship between forage mass and winter pasture height in ICLS conducted in highland and lowland. It was demonstrated that in lowland such relationship is lower, corroborating the necessity of more studies in these conditions, because the optimum heights preconized for pasture management are originated from studies conducted in highlands.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A conversÃo de florestas em pastagens pode ter um impacto sobre as propriedades e funÃÃes do solo, especialmente em condiÃÃes irrigadas. Partindo da hipÃtese de que a conversÃo de Ãrea natural em Ãrea sob pastagem irrigada altera algumas propriedades do solo, objetivou-se avaliar propriedades quÃmicas, fÃsicas e microbiolÃgicas indicadoras da qualidade do solo, em Ãrea sob pastagem, comparando-a com sua condiÃÃo natural. Para tanto, foram analisados atributos quÃmicos (compartimentos de carbono e nitrogÃnio no solo e lipÃdeos); microbiolÃgicos (carbono e nitrogÃnio da biomassa microbiana, respirometria, populaÃÃes de fungos micorrÃzicos arbusculares e glomalina) e fÃsicos (estabilidade de agregados, curva de retenÃÃo da Ãgua no solo, Ãndice S, e IHO), em diferentes profundidades e classes de agregados, visando estabelecer ligaÃÃes que possibilitassem identificar as alteraÃÃes sofridas no solo. Observou-se de modo geral, que o manejo empregado està conseguindo manter a sustentabilidade do sistema. No entanto, deve-se ressaltar que caracterÃsticas intrÃnsecas, como a textura do solo e densidade radicular das gramÃneas, foram determinantes no comportamento de atributos selecionados, como por exemplo, estabilidade de agregados. Foram observadas alteraÃÃes nos atributos estudados, principalmente na distribuiÃÃo dos mesmos no perfil, promovendo o aumento dos compartimentos de carbono e nitrogÃnio do solo, alÃm do teor de lipÃdeos. Os atributos microbiolÃgicos nÃo sofreram alteraÃÃes significativas, indicando que a pastagem irrigada nÃo influencia negativamente tais atributos. Quanto aos atributos fÃsicos, como CRA, IHO e Ãndice S, houve interferÃncia de caracterÃsticas intrÃnsecas, como por exemplo, a textura na determinaÃÃo da qualidade do solo. / The conversion of forests into pastures may have an impact on the properties and functions of the soil, especially in irrigated conditions. Assuming that the conversion of natural area within the area under irrigated pasture alters some soil properties, aimed to evaluate the chemical, physical and microbiological indicators of soil quality in pasture area, comparing it to its natural condition. To this end, analized the chemical (carbon pools and nitrogen in the soil and lipids); microbiological (carbon and microbial biomass nitrogen, respirometry, populations of arbuscular mycorrhizal fungi and glomalin) and physical attributes (aggregate stability, water retention curve soil, S index and IHO) at different depths and aggregate classes, to establish connections that would enable to identify the changes that occurred in the soil. It was observed generally that the management employee is able to maintain the sustainability of the system. However, it should be noted that intrinsic characteristics such as soil texture and density of the grass root, were decisive in the behavior of selected attributes, such as aggregate stability. There were changes in the attributes studied, mainly in their distribution in the profile, promoting the increase of carbon pools and nitrogen from the soil, beyond the level of lipids. The microbiological attributes did not change significantly, indicating that the irrigated pasture does not adversely affect these attributes. The physical attributes, like CRA IHO and S index, the interference of characteristics, for example, in determining the texture of the soil.

Esta tese teve por objetivo verificar como expansões de área irrigada no país aumentariam o uso de água regional. Para isso, os cenários descritos no Plano Nacional de Recursos Hídricos (PNRH) foram utilizados como política de expansão para a irrigação no país. Os cenários descritos são cenário 1 (água para todos), cenário 2 (água para alguns) e cenário 3 (água para poucos), e são situações hipotéticas reportadas pelo plano. Estes cenários foram adaptados com as informações de áreas potencialmente irrigáveis descritas no estudo do Ministério da Integração Nacional (MI) sobre a Análise Territorial para o Desenvolvimento da Agricultura Irrigada. Para tal, utilizou-se um modelo computável de equilíbrio geral denominado TERM-BR, um modelo dinâmico, bottom-up, inter-regional para as simulações dos cenários de demanda futura para o uso da água. O método de Thornthwaite e Mather foi utilizado para estimar o balanço hídrico climatológico (CWB) para os estados do Nordeste e com isso avaliar a situação da disponibilidade hídrica em condições determinadas nessa região. Diversos trabalhos foram utilizados na elaboração da base de dados com informações municipais (agricultura e consumo humano) e informações estaduais (pecuária e indústria), produtividade das culturas, áreas plantadas e colhidas também foram utilizadas. Os resultados simulados sugerem que as expansões de área irrigada proporcionariam mudanças positivas nas variáveis macroeconômicos como consumo das famílias, investimento, gastos do governo, exportações, PIB para o país. Em relação as variáveis macroeconômicas regionais, o estado do Mato Grosso se destacaria em todos os cenários e apresentaria uma mudança no PIB e investimento maior no cenário 1. Expansões de área irrigada na região Centro-Oeste e Norte são viáveis em todos os cenários, especialmente nos estados do Mato Grosso, Goiás, Tocantins, Pará e Minas Gerais na região Sudeste. A maior mudança percentual no uso da água ocorreria na soja e no algodão e o maior volume de uso de água (milhões de metros cúbicos) ocorreria na cultura da cana de açúcar e no arroz. Os resultados da interação entre o modelo TERM-BR e o método de CWB para os estados do Nordeste indicam que os estados de Alagoas e Pernambuco seriam os mais propensos a ter problemas com a disponibilidade hídrica. O aumento no uso de água por região hidrográfica é condizente com o proposto no PNRH e esse aumento deveria ser maior nas regiões hidrográficas do Tocantins-Araguaia (Tocantins, Pará, Mato Grosso e Goiás) e no Atlântico Nordeste Ocidental nos estados do Maranhão e Pará. / This dissertation aimed to verify how expansions of irrigated area in the country would increase the regional water use. For this, the scenarios described in the National Water Resources Plan (PNRH in Portuguese) were used as policy for expansion of irrigation in the country. The scenarios related are scenario 1 (water for all), scenario 2 (water for some) and scenario 3 (water for few), and are hypothetical situations reported by the plan. These scenarios were adapted with the information about irrigable areas described by Ministry of National Integration (MI) on the Territorial Analysis for the Development of Irrigated Agriculture. A computable general equilibrium model namely TERM-BR was used in the simulation, this is dynamic, bottom-up, interregional model for simulations of scenarios for water. The Thornthwaite and Mather method was employed to estimate the Climatic Water Balance (CWB) for Northeastern states and to assess the water availability situation under specific conditions in that region. Several studies were compiled to elaborate the database; some with municipal information (agriculture and human consumption) and others with state information (livestock and industry). Crop productivity, and planted and harvested areas were also used. The results suggest that the expansions in the national irrigated areas would provide positive changes in macroeconomic variables such as household consumption, investment, government spending, exports, and national GDP. Mato Grosso state would stand out in all the scenarios regarding regional macroeconomic variables, and change in regional GDP and investment would be greater in scenario 1. Expansions in the Center-West and North regions are feasible in all scenarios, especially in Mato Grosso, Goiás, Tocantins, Pará and Minas Gerais state. The highest percentage change in water use would occur in soybeans and cotton crops and the largest volume of water use (millions of cubic meters) would occur in sugar cane and rice crop. The results for the interaction between the TERM-BR model and CWB method for the Northeastern states indicate that, Alagoas and Pernambuco state would be the most likely to have problems with water availability. The increase in water use by hydrographic region is consistent with that proposed in the PNRH, and this increase should be higher in the Tocantins-Araguaia hydrographic regions (Tocantins, Pará, Mato Grosso and Goiás) and in the Western Northeast Atlantic in Maranhão and Pará state.