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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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| Streck,Nereu A.; Uhlmann,Lilian O.; Gabriel,Luana F.. |
| The objective of this study was to simulate leaf development of cultivated rice genotypes and weedy red rice biotypes in climate change scenarios at Santa Maria, RS, Brazil. A leaf appearance (LAR) model adapted for rice was used to simulate the accumulated leaf number, represented by the Haun Stage, from crop emergence to flag leaf appearance (EM-FL). Three cultivated rice genotypes and two weedy red rice biotypes in six emergence dates were used. The LAR model was run for each emergence date using 100 years of synthetic daily weather data and six climate scenarios, including current, +1, +2, +3, +4 and +5 ºC increase in mean air temperature, with symmetric and asymmetric increase in daily minimum and maximum temperature. The increase in air temperature... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Oryza sativa; Global warming; Plant competition; Climate change; Nitrogen management. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662013000200010 |
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| Hirzel,Juan; Pedreros,Alberto; Cordero,Karla. |
| Nutritional management in rice (Oryza sativa L.) crops is mainly associated with N fertilization, which is difficult to adjust in field conditions due to variations in soil type and climatic conditions. Between 28 000 and 46 000 ha per year is dedicated to rice production in Chile and profits depend on fertilization. A field experiment determine the effect of N rates and split N fertilization on grain yield and its components was carried out in two locations during two consecutive seasons (2007 to 2009), where five N rates and five split N fertilizations were evaluated. The locations were in Parral (36º2 S; 72º08 W, Vertisol) and San Carlos (36º19 S; 71º59 W, Inceptisol), with N rates of 80, 100, 120, 140, and 160 kg ha-1 applied in different... |
| Tipo: Journal article |
Palavras-chave: Irrigated rice; Nitrogen management; Rice productivity. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000300015 |
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