Dissertations and Theses

Summary

In this work, several aspects of CO2 emission (FCO2) in a Red Latosol in sugarcane areas were evaluated on the management systems of cane burned (CQ) and raw cane (CC), in the northeast of the State of São Paulo. In the experiment 1 (year 2007), the mean FCO2 was 39% higher in the QC area (2.87 μmol m-2 s-1) when compared to CC (2.06 μmol m-2 s-1) at over a period of 70 days of evaluation. The models fitted to the FCO2 experimental semivariograms were, for the most part, exponential in both areas. The emission maps were homogeneous after a period of drought. Soil organic matter content and soil carbon stock (0-0.25 m) were 13 and 20%, respectively, higher in CQ when compared to CC. The degree of humification of soil organic matter and its interaction with soil density was an important factor, not only in the differentiation of the CO2 emission between the different management systems. In the experiment 2 (year of 2008), the anisotropic characterization of the studied variables through the fractal dimension (DF) was conducted in different directions (0o, 45o, 90o and 135o) in relation to the planting lines (0o). The water free porosity (PLA) property was one of the main factors related to the spatial variability of FCO2, regardless of the directions. DF values were significantly lower in the sugarcane plantation, indicating, in addition to the anisotropy of this property, greater FCO2 homogeneity in the 0o direction. PLA has been shown to be an important property in the understanding of SPCO2 spatiotemporal variability, especially in areas of burned sugarcane.