Fluxo de óxido nitroso (N2O) do solo de monocultivos e da integração lavoura-pecuária

• Autor(a) principal: Cruz, Guilherme Momo
• Data de Publicação: 2022
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Biblioteca Digital de Monografias da UFMT
• Texto Completo: http://bdm.ufmt.br/handle/1/2503
• topic: CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA; Gases de Efeito Estufa; Mitigação; Manejo do solo; Greenhouse Gases; Mitigation; Soil management

Nitrous oxide (N2O) is considered one of the main greenhouse gases that interfere in the radioactive balance of the atmosphere and in the chemistry of ozone in the stratosphere (O3). The concentration of this gas in the atmosphere has increased by about 20% compared to the pre-industrial era. Worldwide, agricultural soils contribute around 60% of anthropogenic N2O emissions. Although the agricultural sector is an important source of N2O, its production systems can also act as mitigators. Therefore, this study aimed to evaluate soil nitrous oxide (N2O) emissions in three different treatments: crop (TR2), pasture (TR3) and crop-livestock integration (TR5), determining the respective N2O fluxes and determining the system with lower N2O emission. The evaluations took place at the Experimental Farm of Embrapa Agrossilvipastoril in Sinop-MT, August 2018 to June 2019. In all, 4 replication were used using a system of manual static chambers and syringes, weekly collections of gas samples and further analysis in the laboratory. With this, the weekly flows were obtained in the aforementioned systems. The analyzes were quantified by chromatography to obtain the gaseous fluxes emitted by the soil and then submitted to Box-Cox transformation and applied the normality test and analysis of variance, Pearson's correlation was also used. The effect of nitrogen fertilization and the rainy season were the factors that most influenced N2O fluxes. The highest peaks occurred after soybean sowing, at the end of September, until the end of November and at corn sowing in the second week of February. The highest N2O flux was observed in TR2, crop with approximately 190 μg N2O-N m-2 h-1 . Treatments 2 and 3 showed a significant difference between them. The average N2O fluxes obtained were 29.06 µg N2O- N m-2 h-1 for TR2, tillage, 21.5 µg N2O-N m-2 h-1 for the ILP system (TR5) and, by last, pasture, with 13.82 µg N2O-N m-2 h-1 . Moisture and precipitation are related to the loss of nitrous oxide to the atmosphere. A positive correlation can be observed between TR2 and precipitation and TR3 and TR5 showed a positive correlation with humidity. The highest fluxes of soil N2O were in the crop, followed by the ILP and with the lowest value in the pasture. In the rainy season, in all treatments, the N2O fluxes were higher when compared to the dry season, and are related to the PPA (Multiannual Plan) of the soil.