Direct measures of soil-surface respiration are needed to evaluate belowground biological processes, forest productivity, and ecosystem responses to global change. Although infra-red gas analyzer {IRGA) methods track reference COz flows in lab studies, questions remain for extrapolating I R G A methods to field conditions. We constructed 10 box lysimeters with homogenized mixtures of sandy loam...

We developed a laboratory method to obtain high precision CO2 mixing ratios in air samples contained in 100 ml glass flasks, which involves extracting air from the flask into a pre-evacuated manifold containing a variable-volume metal bellows. Compressed air from the bellows is then routed to a non-dispersive infrared gas analyzer (IRGA). Tests indicate that this configuration has an overall ac...

O objetivo da pesquisa foi avaliar a influência do protetor, tratamento químico com fungicida e inseticida períodos de armazenamento sementes das cultivares arroz irrigado IRGA 424 RI BR 409, na germinação emergência. Para cada cultivar, o delineamento experimental inteiramente casualizado, em esquema fatorial 3 x 5, quatro repetições. Os três tratamentos foram: 1- + protetor sementes; 2- inset...

The measurement of soil carbon dioxide respiration is a means to gauge biological soil fertility. Test methods for respiration employed in the laboratory vary somewhat, and to date the equipment and labor required have somewhat limited more widespread adoption of such methodologies. The purpose of this research is to compare the results of measured soil CO2 respiration using three methods: (1) ...

Allocation of C to belowground plant structures is one of the most important, yet least well quantified fluxes of C in terrestrial ecosystems. In a literature review of mature forests worldwide, Raich and Nadelhoffer (1989) suggested that total belowground carbon allocation (TBCA) could be estimated from the difference between annual rates of soil respiration and aboveground litterfall. Here we...