Soil organic carbon (SOC) is important not only for improving soil quality but also for contributing to climate change mitigation in agriculture. However, net greenhouse gas (GHG) balances, including methane (CH4) and nitrous oxide (N2O), need to be considered, as practices that increase SOC might increase GHG emissions. Sustainable use of soil resources needs to be assessed over long time periods and across spatial scales; biogeochemical models are useful tools to estimate GHG emissions and corresponding mitigation potentials. A process-based, ecosystem model DayCent that simulates soil carbon and nitrogen dynamics from diverse agroecosystems, has been applied to observe SOC sequestration, GHG emissions and yield in a contrasting climatic region UK and Bangladesh agriculture. The study mainly focus on determination of GHG mitigation potentials under improved management practices in rice based cropland Bangladesh. We hypothesized that alternative management would increase SOC and reduce net GHG emissions. As crop yield is the most important variable for Bangladesh, it was includes in the simulations. Since site test simulations under different management using the DayCent model were satisfactory, the model was used to simulate GHG covering 64 districts of Bangladesh, considering climate, soil and SOC content for the period 1996-2015. An integrated management scenario consisting of irrigation, tillage with residue management, reduced mineral nitrogen fertilizer and manure application increased annual SOC stocks, and offset net GHG emissions while maintaining yield. The model outcome suggests that the “4 per mille” target is feasible for Bangladesh. It is also possible to contribute to the GHG reduction target by 2030 set by policy makers.

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Orientador: Marcelo Andreotti / Banca: Salatier Buzetti / Banca: Elcio Hiroyoshi Yano / Banca: Ciniro Costa / Banca: Agnaldo José Freitas Leal / Resumo: Sistemas produtivos conservacionistas, como integração Lavoura-Pecuária (ILP) e plantio direto (SPD), proporcionam além de aumento na produtividade, a conservação do solo. Desta forma, objetivou em um LATOSSOLO VERMELHO Distroférrico sob condições irrigadas no Cerrado, avaliar: 1) o desempenho produtivo e a qualidade bromatológica das silagens produzidas nos diferentes sistemas de produção avaliados; 2) os componentes da produção e a produtividade do milho em consórcio, nos diferentes espaçamentos e da forragem remanescente; 3) em cortes do outono à primavera, a produtividade de forragem e a sua composição bromatológica após a colheita da silagem; 4) no último corte, verificar além da produtividade de forragem, os teores de macronutrientes e a decomposição da palhada das forrageiras após a dessecação na primavera e seu efeito na soja em sucessão; 5) analisar durante a condução dos sistemas de produção, as alterações nos atributos químicos e densidade do solo na camada de 0 a 0,10 e 0,10 a 0,20 m, ao final de cada ciclo produtivo, além da determinação do estoque de carbono; 6) avaliar o desempenho econômico da ILP sob SPD durante o período de estudo, visando constatar a sustentabilidade e lucratividade de cada sistema. Constatou-se que para produção de grãos ou silagem de grãos úmidos recomenda-se o consórcio do milho com capim-Xaraés, independentemente se em espaçamento entrelinhas de 0,90 ou 0,45 m. Enquanto que, para a produção de silagem de planta inteira, recomenda-se o consórcio do milho com o capim-Tanzânia. A variação de tempo para colheita do milho para produção de silagens ou grãos não interferiu na produção ou composição químico-bromatológica dos capins Xaraés e Tanzânia estabelecidos no consórcio com milho. A adubação nitrogenada das forrageiras após o consórcio com milho não refletiu em incremento na produtividade de... / Abstract: Production systems that enable sustainability in agriculture as integration Crop-Livestock (ILP) and no-tillage (NT), as well as provide increased productivity, the full soil conservation. Thus, aimed in an Oxisol under irrigated conditions LATOSOL the Cerrado, to evaluate: 1) the productive performance and the chemical quality of the silage produced in different production systems; 2) the components of the production and productivity of maize in consortium in different spacing and the remaining forage; 3) to evaluate every autumn cut the spring, forage yield and its chemical composition after harvest of silage; 4) in the last cut, check beyond the forage yield, macronutrient contents and the decomposition of straw fodder after desiccation in the spring and its effect on soybean crop; 5) while driving in production systems, changes in chemical properties and density in the layer 0 to 0,10 and from 0,10 to 0,20 m at the end of each production cycle, in addition to the determination of stock carbon; 6) the ILP's economic performance under no till during the study period, in order to verify the sustainability and profitability of each system. It was found that for grain yield or silage moisture grains recommendes to the consortium of corn with Xaraés grass, whether in row spacing of 0,90 or 0,45 m. For the production of the whole plant silage, it is recommended consortium with corn Tanzaniagrass. The variation in time to harvest corn for silage or grain production did not affect the production or chemical composition of Xaraés and Tanzania grasses set out in consortium with corn. Nitrogen fertilization of forage after the consortium with corn not reflected in an increase in dry matter production and nutritional and chemical composition of grasses in area under nine years in no-tillage system. In irrigated conditions in the Cerrado, aiming increasing soybean yield in succession to tropical forages, ... / Doutor

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This thesis investigates dynamics of determinants of government bond spreads in EMU and non-EMU countries, using non-linear Markov-switching method and Dynamic model averaging. Utilizing Dynamic model averaging we found evidence of three bond pricing regimes - pre-crisis, crisis and post Outright monetary transaction announcements. These three regimes are characteristic for all EMU countries (except Slovak Republic) and Czech Republic. Announcements of OMTs triggered post OMTs announcement regime also in Slovak republic. Third regime is not present in Poland, Hungary and United Kingdom. Moreover United Kingdom has only one regime and is dominated solely by market expectations. We found that there is heterogeneity in the determinants of bond spreads across all examined countries. Moreover we found that spreads are significantly related to market and economic sentiments. JEL Classification F12, F21, F23, H25, H71, H87 Keywords Bond yields, bond spreads, DMA Author's e-mail jan.popadak@fsv.cuni.cz Supervisor's e-mail jaromir.baxa@fsv.cuni.cz

From Cache Valley Dairy Association in Smithfield, Utah, milk from two to three cheese vats plus the corresponding Swiss cheese trimmings, salted cheese, and whey were sampled each week from October 1981 to October 1982. The weights of the Swiss Cheese were recorded. Milk samples were analyzed for fat and protein; cheese samples were analyzed for fat, protein, and moisture; whey samples were analyzed for fat. By using Gauss-Newton nonlinear Least Squares method of iteration, the data was analyzed. Two formulas for predicting Swiss cheese yield were derived. A good relationship was found to exist between Swiss cheese yield and fat and protein. In this study it was found that the season affected the percentage of fat and protein in the milk and thereby the cheese yield. The highest cheese yields corresponded with the months with highest protein and fat percentage in the milk.

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Bibliography: leaves 187-203. Evaluates critically a number of physiological traits which may be related to drought resistance in cereals and examines the feasibility of using these screening techniques in selecting more drought resistant genotypes of barley for South Australia.

Winter wheat is commonly grown in dryland cropping systems in the Pacific Northwest region of semi-arid eastern Oregon. For agronomic, economic, and environmental reasons, it is important to understand the long-term sustainability of such dryland systems. The objective of this study was to evaluate the long-term effects of tillage, nitrogen (N), soil depth, and the influence of precipitation on wheat yields in dry land cropping systems of eastern Oregon. Data were taken from the Tillage/Fertility or "Balenger" experiment, which was established in 1940 by a Soil Conservation employee, and is one of the oldest replicated research experiments in the western United States. The experiment consisted of a winter wheat-summer fallow rotation arranged in a randomized block design with three replications. The main plot consisted of three primary tillage treatments (moldboard plow, offset disk, and subsurface sweep) and subplots consisted of six nitrogen treatments that changed over time and most recently ranged from 0 to 180 kg ha�����. Soil depth of individual plots ranged from 1.2- to 3.0-m. The study was divided into four main time periods (1940-1951, 1952-1961, 1962-1987, and 1988-1997) within which experimental treatments were consistently maintained. The moldboard plow tillage treatment significantly increased yields by more than 300 kg ha����� over the subsurface sweep tillage treatment in all four time periods. Yields with the moldboard plow system were significantly higher than with the offset disk system in time periods 3 and 4. The same trend was evident for mean yield in time periods 1 and 2, but differences were not statistically significant. In time periods 1, 2, and 3, mean yields were higher with the offset disk tillage treatment than the subsurface sweep tillage system, although the differences were not statistically significant. In time period 4, mean yield was higher for the subsurface sweep system than the offset disk treatment, but differences were not statistically significantly. The optimum amount of N for winter wheat differed from year to year, within, and between experiment periods. This was apparently in response to rainfall patterns and improved management factors, specifically more N responsive semi-dwarf varieties. For time period 1, the maximum fertilizer rate was 11.2 kg N ha�����, which tended to produce higher mean grain yields than an application rate of than 0 kg N ha�����, regardless of the quantity or distribution of precipitation. For time period 2, the maximum fertilizer rate was 33.7 kg N ha�����, which produced significantly higher grain yields than an application rate of than 0 kg N ha�����, regardless of the quantity or distribution of precipitation. For time period 3 (1962-1987), which had below-normal annual and growing season precipitation, yield increased with the addition of 45 kg N ha�����. For time period 4 (1988- 1997), which had above-normal annual and growing season precipitation, yield increased with the addition of 90 kg N ha�����. Yield increases at greater rates of N were insignificant. For time periods 3 and 4, maximum mean yield was obtained at an application rate of 135 kg N ha�����. The response of wheat yield to N during dry years was greater for deep (> 2.8 m) soils than for shallow soils. In addition to amount, rainfall distribution during the winter (October to March) and growing (April to June) season significantly affected yield. Results demonstrate the importance of rainfall and nitrogen to winter wheat production in eastern Oregon, and that the most environmentally sound tillage systems are not necessarily the most profitable from farmers' point of view. / Graduation date: 2000