109 resultados para Cereal products


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The DAYCENT biogeochemical model was used to investigate how the use of fertilizers coated with nitrification inhibitors and the introduction of legumes in the crop rotation can affect subtropical cereal production and {N2O} emissions. The model was validated using comprehensive multi-seasonal, high-frequency dataset from two field investigations conducted on an Oxisol, which is the most common soil type in subtropical regions. Different N fertilizer rates were tested for each N management strategy and simulated under varying weather conditions. DAYCENT was able to reliably predict soil N dynamics, seasonal {N2O} emissions and crop production, although some discrepancies were observed in the treatments with low or no added N inputs and in the simulation of daily {N2O} fluxes. Simulations highlighted that the high clay content and the relatively low C levels of the Oxisol analyzed in this study limit the chances for significant amounts of N to be lost via deep leaching or denitrification. The application of urea coated with a nitrification inhibitor was the most effective strategy to minimize {N2O} emissions. This strategy however did not increase yields since the nitrification inhibitor did not substantially decrease overall N losses compared to conventional urea. Simulations indicated that replacing part of crop N requirements with N mineralized by legume residues is the most effective strategy to reduce {N2O} emissions and support cereal productivity. The results of this study show that legumes have significant potential to enhance the sustainable and profitable intensification of subtropical cereal cropping systems in Oxisols.

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Alternative sources of N are required to bolster subtropical cereal production without increasing N2O emissions from these agro-ecosystems. The reintroduction of legumes in cereal cropping systems is a possible strategy to reduce synthetic N inputs but elevated N2O losses have sometimes been observed after the incorporation of legume residues. However, the magnitude of these losses is highly dependent on local conditions and very little data are available for subtropical regions. The aim of this study was to assess whether, under subtropical conditions, the N mineralised from legume residues can substantially decrease the synthetic N input required by the subsequent cereal crop and reduce overall N2O emissions during the cereal cropping phase. Using a fully automated measuring system, N2O emissions were monitored in a cereal crop (sorghum) following a legume pasture and compared to the same crop in rotation with a grass pasture. Each crop rotation included a nil and a fertilised treatment to assess the N availability of the residues. The incorporation of legumes provided enough readily available N to effectively support crop development but the low labile C left by these residues is likely to have limited denitrification and therefore N2O emissions. As a result, N2O emissions intensities (kg N2O-N yield−1 ha−1) were considerably lower in the legume histories than in the grass. Overall, these findings indicate that the C supplied by the crop residue can be more important than the soil NO3− content in stimulating denitrification and that introducing a legume pasture in a subtropical cereal cropping system is a sustainable practice from both environmental and agronomic perspectives.

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This research consists of a broad study in three parts of the social and environmental reporting practices of organisations operating in or sourcing products from a developing country, in this case Bangladesh. The first part of this study explores the social and environmental disclosure practices of the Bangladesh Garment Manufacturers and Exporters Association (BGMEA), the body responsible for organising the activities of 4,200 entities involved in the export of garments from Bangladesh. By way of interview, this part documents the opinions of numerous senior executives from the BGMEA with regard to any changes in the degree of social and environmental pressures since 1985. Utilising a complementary theoretical perspective that includes legitimacy theory, stakeholder theory and institutional theory this part then performs an analysis of the BGMEA's annual reports (1987-2005), t o explore the link between the perceived pressures and changes entailed therein and the social and environmental disclosure practices of the BGMEA across the period of analysis. The results show that the disclosure practices of BGMEA appear to be directly driven by the changing expectations of multinational buying companies- the group deemed to be the most powerful stakeholder group. This section is the first known study to interview managers from a large organisation in a developing country about shifting stakeholder expectations and then to link these changing expectations to annual report disclosures across an extended period of analysis. The findings then directly lead to the second major part of this thesis which investigates the social and environmental disclosure practices of two major multinational buying companies: Nike and H&M. Adopting a joint consideration of legitimacy theory and media agenda setting theory, this second part investigates the linkage between negative media attention and positive corporate social and environmental disclosures over a 19 year period. The results support the view that for those industry-related social and environmental issues that attract the greatest amount of negative media attention, these companies react by providing positive social and environmental disclosures. The results were particularly significant in relation to labour practices in developing countries-the issue that attracts the greatest amount of negative media attention for the companies in question. While the second part demonstrates that the media influences particular disclosure practices, the third part of the thesis shows what drives the media. Based on the speculation provided in the second part, the third part tests the proposition that the media is an important ally of NGOs in their quest to influence change in corporate accountabilities. Through the use of interviews, the results of this part of the study provide evidence to support previously untested perspectives about NGOs' utilisation of the m edia. The results reveal that NGOs use the media because the media is responsible for creating real changes in the operations and disclosure policies of organisations sourcing products from Bangladesh. The various pressures impacting the activities of organisations operating in or sourcing products from developing countries constitutes a fascinating area of investigation, and it is hoped that this study will motivate further research in this area.

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Although hundreds of thousands of organic products are traded on a daily basis, it is less known how imported organic products are evaluated by consumers in an importing country. The paper analyzes Japanese wine point of sale (POS) data to examine whether consumers differentiate between local and imported organic products. The results of our hedonic analyses show that the premium for imported organic red (white) wines is about 42.996 % (8.872 %) while that for domestic red (white) organic wines is about 6.440 % (1.214 %), implying that Japanese consumers pay higher premiums for imported organic agricultural products than for those produced in Japan.