Química Nova
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/13323
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Item Indicadores químicos de qualidade da matéria orgânica de solo da sub-bacia do Rio das Mortes sob manejos diferenciais de cafeeiro(Sociedade Brasileira de Química, 2008) Oliveira Júnior, Antônio Claret; Silva, Carlos Alberto; Curi, Nilton; Guilherme, Luiz Roberto Guimarães; Rangel, Otacílio José PassosThis work evaluated the chemical quality of organic matter (OM) of a Brazilian Oxisol cultivated with coffee plants, under organic and conventional managements. Total organic C (TOC), light fraction C (LF-C) and C in humic (HA-C) and fulvic (FA-C) acids fractions was measured. Amongst the evaluated indexes, TOC and LF-C discriminated better OM attributes as a function of management. The stratification ratio (TOC5-10cm/TOC10-20cm) did not show differences between the systems studied. The organic system can contribute to the sustainability of coffee plantations in Brazil, because it maintains the chemical attributes of OM closer to the indexes verified under forest conditions.Item Sorção e lixiviação de tiametoxam em solos tratados com lodo de esgoto e cultivados com cafeeiro(Sociedade Brasileira de Química, 2012) Magalhães, Ciro Augusto de Souza; Lima, José Maria de; Costa, Alisson Lucrécio da; Silva, Evânia Geralda da; Silva, Carlos Alberto; Bettiol, Wagner; Nóbrega, Julio Cesar Azevedo; Guimarães, Paulo Tácito GontijoThe objective of this study was to evaluate the sorption and leaching of thiamethoxam in dystrophic Red Yellow Latosol (LVAd), dystroferric Red Latosol (LVdf) and Red-Yellow Argisol (PVAd) with coffee under the effect of sewage sludge doses. There was thiamethoxam sorption decreasing at higher doses of sewage sludge in LVAd and LVdf. In the PVAd, sorption was higher in samples that received the highest dose of sewage sludge. At 150 days after the application of thiamethoxam, the compound began to be detected in the effluent, in all soils. Dissolved organic carbon had no influence on the thiamethoxam leaching.Item Variações de curto prazo nas emissões de CO2 do solo em diferentes sistemas de manejo do cafeeiro(Sociedade Brasileira de Química, 2009) D’Andréa, Alexandre Fonseca; Silva, Marx Leandro Naves; Curi, Nilton; Freitas, Diego Antonio França de; Roscoe, Renato; Guimarães, Paulo Tácito GontijoSoil CO2 emissions represent an important component of carbon global cycle. However, information about short-term alterations of CO2 fluxes in soils of tropical regions are scarce. So, the objective of this study was to evaluate such variations in coffee plantations in Latosol (Oxisol). The CO2 emissions were not affected by environmental abiotic factors, such as temperature and soil water evaporation, but they were significantly correlated with the carbon content of microbial biomass (R=0.90, P<0.05). It happens a close relationship between root activity and soil CO2 emission in coffee plantations.