Título:	Fluxos de N2O e atributos do solo em sistemas integrados de produção de longa duração sob dois níveis de P e K.
Autor(es):	Santos, Divina Cleia Resende
E-mail do autor:	cleiadivina@hotmail.com
Orientador(es):	Ramos, Maria Lucrécia Gerosa
Coorientador(es):	Carvalho, Arminda Moreira de
Assunto:	Gases - efeito estufa Sistemas integrados Plantio direto Enzimas do solo Mitigação Biomassa microbiana Efeito estufa - emissão de gases
Data de publicação:	23-dez-2020
Data de defesa:	3-jun-2020
Referência:	SANTOS, Divina Cleia Resende. Fluxos de N2O e atributos do solo em sistemas integrados de produção de longa duração sob dois níveis de P e K. 2020. 113 f., il. Tese (Doutorado em Agronomia)—Universidade de Brasília, Brasília, 2020.
Abstract:	No-tillage, based on rotations between pastures and tropical grasses as cover crops, has been used in Brazil as an alternative to sustainable intensification in agricultural systems. The diversity of crops in the crop-livestock integration systems (ILP) results in increases in the labile soil reservoir, the microbial biomass of the soil, and these systems are related to better soil quality, obtained through rotation, succession or intercropping. Cultures. Consequently, the ILP has a greater capacity for mitigating greenhouse gases. Although flows of N-N2O are related to nitrogen fertilization, there is little information about interactions with other nutrients that can alter microbiological properties, and, therefore, N-N2O flows in the soil. In Chapter I, N-N2O emissions were evaluated in two agricultural systems (LC - Continuous washing and ILP - crop-livestock integration system), under two levels of phosphate and potassium fertilization (F1- maintenance fertilization, with half the dose P and K, and F2 - corrective fertilization, recommended dose of P and K). Differentiated fertilization of P and K occurred between 1991 and 2013; after that period, all production systems received the same fertilization with P and K. N-N2O flows were evaluated during two agricultural seasons: 2015/2016 and 2016/2017. The soil properties (NO3; NH4 + and EPSA - pore filled with water), climatic (air temperature and daily precipitation) and chemical properties of the soil were also determined. The daily flows were analyzed using the MIXED of the SAS (Statistical Analysis System v 9.4), considering blocks and samples (nested in fertility levels) as random effects. The daily flows were subjected to an analysis of variance as repeated measures in a daily paired comparison (p <0.05), respectively. The highest peaks of N-N2O occurred at the end of the cycle of the two soybean crops. In the off-season, 60% of the peaks were below 5.00 μg N-N2O m-2 h-1. In the LC system, emissions were higher, regardless of fertility level. Corrective fertilization (F2) increased the emission of N-N2O in relation to the application of the maintenance dose, regardless of management. In chapter II, the same production systems were studied, with the objective of evaluating the effect of two production systems (LC - continuous crop and ILP - crop-livestock integration system) and two levels of fertilization with phosphate and potassium (F1 and F2), the chemical and microbiological attributes of the soil and their relationship with the accumulated flows of N-N2O in two soybean crops. N-N2O flows were measured over two agricultural years, using four static chambers / treatment, from November 2015 to July 2017. Soil collections were performed in the 0-10 cm layer, in the flowering of soybeans, in 2016 and 2017 and the chemical and biochemical attributes of the soil (carbon and nitrogen of the soil microbial biomass, carbon and total N of the soil, organic carbon and total N of the particulate fraction of the soil, available N, humic fractions of the organic carbon and enzymes of the soil) were evaluated soil (β-glucosity, arylsulfatase and acid phosphatase). The cumulative emission of N-N2O showed significant differences between the management systems (P <0.05). in the soil and may have contributed to alter its microbiological attributes. There was no change in the humic fractions in the production systems in the two years of evaluation. The accumulated N-N2O emission showed significant differences between the s soil management systems, only in the first soybean crop. The phosphate and potassium fertilization differentiated in previous years may have promoted the greatest entry of carbon in the soil and altered its microbiological attributes. The ILP-F1 and ILP-F2 production systems were more correlated with soil enzymatic activity (Aryl, Phos and β-Gluc), CP and MAC in the two years of evaluation. Arisulfatase and phosphatase which are inversely related to N-N2O emission, and this was observed in the ILP.
Unidade Acadêmica:	Faculdade de Agronomia e Medicina Veterinária (FAV)
Informações adicionais:	Tese (doutorado)—Universidade de Brasília, Faculdade de Agronomia e Medicina Veterinária, Programa de Pós-Graduação em Agronomia, 2020.
Programa de pós-graduação:	Programa de Pós-Graduação em Agronomia
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
Agência financiadora:	Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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