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Registros recuperados: 24 | |
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Gaigne, Carl; Riou, Stephane; Thisse, Jacques-Francois. |
There is a wide consensus among international institutions and national governments in favor of compact (i.e. densely populated) cities as a way to improve the ecological performance of the transport system. Indeed, when both the intercity and intra-urban distributions of activities are given, a higher population density makes cities more environmentally friendly as the average commuting length is reduced. However, when we account for the possible relocation of activities within and between cities in response to a higher population density, the latter may cease to hold. Because changes in population density affect land rents and wages, firms and workers re-optimize and choose new locations. We show that this may reshape the urban system in a way that... |
Tipo: Working Paper |
Palavras-chave: Greenhouse gas; Commuting costs; Transport costs; Cities; Environmental Economics and Policy; D61; F12; Q54; Q58; R12. |
Ano: 2012 |
URL: http://purl.umn.edu/121692 |
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Weiler,Douglas Adams; Tornquist,Carlos Gustavo; Zschornack,Tiago; Ogle,Stephen Michael; Carlos,Filipe Selau; Bayer,Cimélio. |
ABSTRACT The DayCent ecosystem model, widely tested in upland agroecosystems, was recently updated to simulate waterlogged soils. We evaluated the new version in a paddy rice experiment in Southern Brazil. DayCent was used to simulate rice yield, soil organic carbon (SOC), and soil CH4 fluxes. Model calibration was conducted with a multiple-year dataset from the conventional tillage treatment, followed by a validation phase with data from the no-tillage treatment. Model performance was assessed with statistics commonly used in modeling studies: root mean square error (RMSE), model efficiency (EF), and mean difference (M). In general, DayCent slightly underestimated rice yields under no-tillage (by 0.07 Mg ha-1, or 9.2 %) and slightly overestimated soil C... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Modeling; Soil potential redox; Flooded soil; Greenhouse gas; Soil tillage. |
Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832018000100523 |
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McPhee, Malcolm J.; Edwards, Clare; Meckiff, Jim; Ballie, Neil; Schneider, Derek; Arnott, Paul; Cowie, Annette l.; Savage, Darryl; Lamb, David; Guppy, Chris; McCorkell, Bruce E.; Hegarty, Roger S.. |
Special Edition Sheep and Cattle Production in New South Wales |
Tipo: Article |
Palavras-chave: Greenhouse gas; High fertility; Low fertility; Pasture production; Farm Management. |
Ano: 2011 |
URL: http://purl.umn.edu/121466 |
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Moterle,Diovane Freire; Silva,Leandro Souza da; Moro,Vagner João; Bayer,Cimélio; Zschornack,Tiago; Avila,Luis Antonio de; Bundt,Ângela da Cas. |
Paddy rice fields may contribute to methane (CH4) emission from soil due to anaerobic conditions after flooding. Alternatives to continuous flooding irrigation in rice have been developed to mitigate CH4 efflux into the atmosphere. This study aims to investigate the effects of irrigation managements in the CH4 efflux during the rice growing season. An experiment was carried out at in Santa Maria, Rio Grande do Sul State, Brazil, during 2007/08 and 2009/10 growing seasons. The treatments were continuous flooding and intermittent irrigation in 2007/08 and continuous flooding, intermittent irrigation and flush irrigation in 2009/10. Intermittent irrigation is effective in mitigating CH4 efflux from rice fields when climatic conditions enable water absence... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Greenhouse gas; Flooding irrigation; Intermittent irrigation; Redox potential. |
Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000200014 |
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Rachwal,Marcos Fernando Glück; Zanatta,Josiléia Acordi; Dieckow,Jeferson; Denega,Genuir Luis; Curcio,Gustavo Ribas; Bayer,Cimélio. |
Soil can be either source or sink of methane (CH4), depending on the balance between methanogenesis and methanotrophy, which are determined by pedological, climatic and management factors. The objective of this study was to assess the impact of drainage of a highland Haplic Histosol on CH4 fluxes. Field research was carried out in Ponta Grossa (Paraná, Brazil) based on the measurement of CH4 fluxes by the static chamber method in natural and drained Histosol, over one year (17 sampling events). The natural Histosol showed net CH4 eflux, with rates varying from 238 µg m-2 h-1 CH4, in cool/cold periods, to 2,850 µg m-2 h-1 CH4, in warm/hot periods, resulting a cumulative emission of 116 kg ha-1 yr-1 CH4. In the opposite, the drained Histosol showed net... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Greenhouse gas; Water sources; Water-table; Gravimetric moisture; Air temperature; Rainfall. |
Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832014000200013 |
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Carvalho,Márcia Thaís de Melo; Madari,Beáta Emöke; Leal,Wesley Gabriel de Oliveira; Costa,Adriana Rodolfo da; Machado,Pedro Luiz Oliveira de Almeida; Silveira,Pedro Marques da; Moreira,José Aloísio Alves; Heinemann,Alexandre Bryan. |
The objective of this work was to measure the fluxes of N2O‑N and NH3‑N throughout the growing season of irrigated common‑bean (Phaseolus vulgaris), as affected by mulching and mineral fertilization. Fluxes of N2O‑N and NH3‑N were evaluated in areas with or without Congo signal grass mulching (Urochloa ruziziensis) or mineral fertilization. Fluxes of N were also measured in a native Cerrado area, which served as reference. Total N2O‑N and NH3‑N emissions were positively related to the increasing concentrations of moisture, ammonium, and nitrate in the crop system, within 0.5 m soil depth. Carbon content in the substrate and microbial biomass within 0.1 m soil depth were favoured by Congo signal grass and related to higher emissions of N2O‑N, regardless of... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cerrado; Climate change; Greenhouse gas; N fertilization; Nitrous oxide; No‑tillage. |
Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2013000500003 |
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Ribaudo, Marc; Delgado, Jorge; Hansen, LeRoy T.; Livingston, Michael J.; Mosheim, Roberto; Williamson, James M.. |
Nitrogen is an important agricultural input that is critical for crop production. However, the introduction of large amounts of nitrogen into the environment has a number of undesirable impacts on water, terrestrial, and atmospheric resources. This report explores the use of nitrogen in U.S. agriculture and assesses changes in nutrient management by farmers that may improve nitrogen use effi ciency. It also reviews a number of policy approaches for improving nitrogen management and identifi es issues affecting their potential performance. Findings reveal that about two-thirds of U.S. cropland is not meeting three criteria for good nitrogen management. Several policy approaches, including fi nancial incentives, nitrogen management as a condition of farm... |
Tipo: Report |
Palavras-chave: Reactive nitrogen; Nitrogen management; Fertilizer; Water quality; Greenhouse gas; Economic incentives; Conservation policy; Regulation; Environmental Economics and Policy; Resource /Energy Economics and Policy. |
Ano: 2011 |
URL: http://purl.umn.edu/118022 |
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Registros recuperados: 24 | |
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