Bioethanol from sugarcane is becoming an increasingly important alternative energy source worldwide as it is considered to be both economically and environmentally sustainable. Besides being produced from a tropical perennial grass with high photosynthetic efficiency, sugarcane ethanol is commonly associated with low N fertilizer use because sugarcane from Brazil, the world's largest sugarcane producer, has a low N demand. In recent years, several models have predicted that the use of sugarcane ethanol in replacement to fossil fuel could lead to high greenhouse gas (GHG) emission savings. However, empirical data that can be used to validate model predictions and estimates from indirect methodologies are scarce, especially with regard to emissions associated with different fertilization methods and agricultural management practices commonly used in sugarcane agriculture in Brazil. In this study, we provide in situ data on emissions of three GHG (CO₂, N₂O, and CH₄) from sugarcane soils in Brazil and assess how they vary with fertilization methods and management practices. We measured emissions during the two main phases of the sugarcane crop cycle (plant and ratoon cane), which include different fertilization methods and field conditions. Our results show that N₂O and CO₂ emissions in plant cane varied significantly depending on the fertilization method and that waste products from ethanol production used as organic fertilizers with mineral fertilizer, as it is the common practice in Brazil, increase emission rates significantly. Cumulatively, the highest emissions were observed for ratoon cane treated with vinasse (liquid waste from ethanol production) especially as the amount of crop trash on the soil surface increased. Emissions of CO₂ and N₂O were 6.9 kg ha⁻¹ yr⁻¹ and 7.5 kg ha⁻¹ yr⁻¹, respectively, totaling about 3000 kg in CO₂ equivalent ha⁻¹ yr⁻¹.

We estimated carbon and nitrogen stocks in aboveground biomass (AGB) and belowground biomass (BGB) along an elevation range in forest sites located on the steep slopes of the Serra do Mar on the north coast of the State of São Paulo, southeast Brazil. In elevations of 100 m (lowland), 400 m (submontane), and 1000 m (montane) four 1‐ha plots were established, and above‐ (live and dead) and belowground (live and dead) biomass were determined. Carbon and nitrogen concentrations in each compartment were determined and used to convert biomass into carbon and nitrogen stocks. The carbon aboveground stock (C_AGB) varied along the elevation range from approximately 110 to 150 Mg·ha⁻¹, and nitrogen aboveground stock (N_AGB), varied from approximately 1.0 to 1.9 Mg·ha⁻¹. The carbon belowground stock (C_BGB) and the nitrogen belowground stock (N_BGB) were significantly higher than the AGB and varied along the elevation range from approximately 200–300 Mg·ha⁻¹, and from 14 to 20 Mg·ha⁻¹, respectively. Finally, the total carbon stock (C_TOTAL) varied from approximately 320 to 460 Mg·ha⁻¹, and the nitrogen total stock (N_TOTAL) from approximately 15 to 22 Mg·ha⁻¹. Most of the carbon and nitrogen stocks were found belowground and not aboveground as normally found in lowland tropical forests. The above‐ and belowground stocks, and consequently, the total stocks of carbon and nitrogen increased significantly with elevation. As the soil and air temperature also decreased significantly with elevation, we found a significantly inverse relationship between carbon and nitrogen stocks and temperature. Using this inverse relationship, we made a first approach estimate that an increase of 1°C in soil temperature would decrease the carbon and nitrogen stocks in approximately 17 Mg·ha⁻¹and 1 Mg·ha⁻¹of carbon and nitrogen, respectively.

Duarte-Neto, P., Lessa, R., Stosic, B., and Morize, E. 2008. The use of sagittal otoliths in discriminating stocks of common dolphinfish (Coryphaena hippurus) off northeastern Brazil using multishape descriptors. – ICES Journal of Marine Science, 65: 1144–1152.