• Authors:
    • Higarashi, M. M.
    • Oliveira, P. A. V. de
    • Denega, G. L.
    • Bayer, C.
    • Silveira Nicoloso, R. da
    • Correa, J. C.
    • Santos Lopes, L. dos
  • Source: Ciencia Rural
  • Volume: 43
  • Issue: 2
  • Year: 2013
  • Summary: Assessments of soil carbon dioxide (CO 2), methane (CH 4), and nitrous oxide (N 2O) emissions are critical for determination of the agricultural practices' potential to mitigate global warming. This study evaluated the photoacoustic spectroscopy (PAS) for the assessment of soil greenhouse gases (GHG) fluxes in comparison to the standard gas chromatography (GC) method. Two long-term experiments with different tillage and cropping systems over a Paleudult were evaluated using static chambers. PAS measurements of CO 2 and N 2O concentrations showed good relationship and linearity (R 2=0.98 and 0.94, respectively) with GC results. However, CH 4 measurements were significantly affected by air sample moisture which interfered on CH 4 detection by PAS. Overestimation of CO 2 and N 2O concentrations in air samples determined by PAS (14.6 and 18.7%, respectively) were also related to sampling moisture. CO 2 and N 2O fluxes showed good agreement between methods (R 2=0.96 and 0.95, respectively), though PAS overestimated fluxes by 18.6 and 13.6% in relation to GC results, respectively. PAS showed good sensitivity and was able to detect CO 2 and N 2O fluxes as low as 332 mg CO 2 m -2 h -1 and 21g N 2O m -2 h -1. PAS analyzer should be detailed calibrated to reduce humidity interference on CO 2, CH 4 and N 2O concentrations measurements avoiding overestimation or erroneous determination of soil GHG fluxes.
  • Authors:
    • Pellegrino Cerri,Carlos Eduardo
    • Galdos,Marcelo Valadares
    • Nunes Carvalho,Joao Luis
    • Feigl,Brigitte Josefine
    • Cerri,Carlos Clemente
  • Source: Scientia Agricola
  • Volume: 70
  • Issue: 5
  • Year: 2013
  • Summary: Strategies to mitigate climate change through the use of biofuels (such as ethanol) are associated not only to the increase in the amount of C stored in soils but also to the reduction of GHG emissions to the atmosphere. This report mainly aimed to propose appropriate methodologies for the determinations of soil organic carbon stocks and greenhouse gas fluxes in agricultural phase of the sugarcane production. Therefore, the text is a piece of contribution that may help to obtain data not only on soil carbon stocks but also on greenhouse gas emissions in order to provide an accurate life cycle assessment for the ethanol. Given that the greenhouse gas value is the primary measure of biofuel product quality, biorefiners that can show a higher offset of their product will have an advantage in the market place.
  • Authors:
    • Moraes, O. L. L. de
    • Fontana, D. C.
    • Rodrigues, C. P.
    • Roberti, D. R.
  • Source: Revista Brasileira de Meteorologia
  • Volume: 28
  • Issue: 1
  • Year: 2013
  • Summary: The increasing on the greenhouse gases (GHG) emissions is today one of the main environmental problems, which can significantly affect human activities and land ecosystems. One of the main GHG is CO 2, which has been emitted indiscriminately due to the current lifestyle, as well as the intensification of agricultural activities. In this context, the objective of this investigation was to study the relationship between the spectral behavior of soybean during the crop cycle, using NDVI (Normalized Difference Vegetation Index), and the CO 2 fluxes, calculated by the eddy covariance method, generating information and methodology to investigate the carbon exchange in a soybean crop area in the State of Rio Grande do Sul, during the 2008/2009 soybean crop. For this, Landsat images 5 (TM), the phenological information and collected data from micrometeorological station throughout the development cycle of soybean were used. The results showed that the temporal pattern of CO 2 flux during the day was cyclical, showing negative values (capture) during daytime and positive values (liberation) at night. The global solar radiation determines the magnitude of the trapping of CO 2 by soybean, but the flow is modulated by the phenological stage of the crop. The photosynthetic activity of soybean plants is higher during the vegetative stage, coinciding to the higher incidence of solar radiation and the greater photosynthetic apparatus. The NDVI, obtained from Landsat images, is an indicator of the evolution of soybean biomass during the cycle. NDVI and negative CO 2 flow (capture) are correlated during the day. Therefore, remote sensing techniques show potentiality in generating of useful information on CO 2 exchange between the surface and atmosphere.
  • Authors:
    • Conant, R.
    • Cerri, C.
    • Signor, D.
  • Source: Environmental Research Letters
  • Volume: 8
  • Issue: 1
  • Year: 2013
  • Summary: Among the main greenhouse gases (CO2, CH4 and N2O), N2O has the highest global warming potential. N2O emission is mainly connected to agricultural activities, increasing as nitrogen concentrations increase in the soil with nitrogen fertilizer application. We evaluated N2O emissions due to application of increasing doses of ammonium nitrate and urea in two sugarcane fields in the mid-southern region of Brazil: Piracicaba (Sao Paulo state) and Goianesia (Goias state). In Piracicaba, N2O emissions exponentially increased with increasing N doses and were similar for urea and ammonium nitrate up to a dose of 107.9 kg ha(-1) of N. From there on, emissions exponentially increased for ammonium nitrate, whereas for urea they stabilized. In Goianesia, N2O emissions were lower, although the behavior was similar to that at the Piracicaba site. Ammonium nitrate emissions increased linearly with N dose and urea emissions were adjusted to a quadratic equation with a maximum amount of 113.9 kg N ha(-1). This first effort to measure fertilizer induced emissions in Brazilian sugarcane production not only helps to elucidate the behavior of N2O emissions promoted by different N sources frequently used in Brazilian sugarcane fields but also can be useful for future Brazilian ethanol carbon footprint studies.
  • Authors:
    • Dias, C.
    • La Scala, N.
    • Cerri, C.
    • Silva-Olaya, A.
    • Cerri, C.
  • Source: Environmental Research Letters
  • Volume: 8
  • Issue: 1
  • Year: 2013
  • Summary: Soil tillage and other methods of soil management may influence CO2 emissions because they accelerate the mineralization of organic carbon in the soil. This study aimed to quantify the CO2 emissions under conventional tillage (CT), minimum tillage (MT) and reduced tillage (RT) during the renovation of sugarcane fields in southern Brazil. The experiment was performed on an Oxisol in the sugarcane-planting area with mechanical harvesting. An undisturbed or no-till (NT) plot was left as a control treatment. The CO2 emissions results indicated a significant interaction (p < 0.001) between tillage method and time after tillage. By quantifying the accumulated emissions over the 44 days after soil tillage, we observed that tillage-induced emissions were higher after the CT system than the RT and MT systems, reaching 350.09 g m(-2) of CO2 in CT, and 51.7 and 5.5 g m(-2) of CO2 in RT and MT respectively. The amount of C lost in the form of CO2 due to soil tillage practices was significant and comparable to the estimated value of potential annual C accumulation resulting from changes in the harvesting system in Brazil from burning of plant residues to the adoption of green cane harvesting. The CO2 emissions in the CT system could respond to a loss of 80% of the potential soil C accumulated over one year as result of the adoption of mechanized sugarcane harvesting. Meanwhile, soil tillage during the renewal of the sugar plantation using RT and MT methods would result in low impact, with losses of 12% and 2% of the C that could potentially be accumulated during a one year period.
  • Authors:
    • Thorburn, P.
    • Ruane, A.
    • Marin, F.
    • Jones, M.
    • Singels, A.
  • Source: An International Journal of Sugar Crops and Related Industries
  • Volume: 115
  • Issue: 1380
  • Year: 2013
  • Summary: Future climate change is expected to have important consequences for sugarcane production, and reliable predictions of crop response to climate change are necessary to plan adaptation strategies. The objective of this study was to assess the use of global climate models (GCMs) and a crop simulation model for predicting climate change impacts on sugarcane production. The Canegro model was used to simulate growth and development of sugarcane crops under typical management conditions at three sites (irrigated crops at Ayr, Australia; rainfed crops at Piracicaba, Brazil and La Mercy, South Africa) for current and three future climate scenarios. The baseline scenario consisted of a 30-year time series of historical daily weather records and atmospheric CO2 concentration ([CO2]) set at 360 ppm. Future climate scenarios were derived from three GCMs for the A2 greenhouse gas emission scenario and [CO2] set at 734 ppm. The three GCMs were chosen to represent the uncertainty in projected rainfall changes. Future cane yields are expected to increase at all three sites, ranging from +4% for Ayr, to +9% and +20% for Piracicaba and La Mercy. The uncertainty of these predictions correlates with the magnitude of the predicted yield increase. Canopy development was accelerated at all three sites by increased temperature, which led to increased interception of radiation, increased transpiration, and slight increases in drought stress at rainfed sites. For the high potential sites (Ayr and Piracicaba), yield increases were limited by large increases in maintenance respiration which consumed most of the daily assimilate when high biomass was achieved. A weakness of the climate data used was the assumption of no change in rainfall distribution, solar radiation and relative humidity-variables that are crucial in determining the water status of rainfed sugarcane. Crop model aspects that need refinement include improved simulation of (1) elevated [CO2] effects on crop photosynthesis and transpiration, and (2) high temperature effects on crop development, photosynthesis and respiration.
  • Authors:
    • Pereira, G. T.
    • Panosso, A. R.
    • Cerri, C. E. P.
    • Bicalho, E. S.
    • Teixeira, D. D. B.
    • La Scala, N.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 167
  • Year: 2013
  • Summary: The characterization of soil CO2 emissions (FCO2) is important for the study of the global carbon cycle. This phenomenon presents great variability in space and time, a characteristic that makes attempts at modeling and forecasting FCO2 challenging. Although spatial estimates have been performed in several studies, the association of these estimates with the uncertainties inherent in the estimation procedures is not considered. This study aimed to evaluate the local, spatial, local-temporal and spatial-temporal uncertainties of short-term FCO2 after harvest period in a sugar cane area. The FCO2 was featured in a sampling grid of 60 m x 60 m containing 127 points with minimum separation distances from 0.5 to 10 m between points. The FCO2 was evaluated 7 times within a total period of 10 days. The variability of FCO2 was described by descriptive statistics and variogram modeling. To calculate the uncertainties, 300 realizations made by sequential Gaussian simulation were considered. Local uncertainties were evaluated using the probability values exceeding certain critical thresholds, while the spatial uncertainties considering the probability of regions with high probability values together exceed the adopted limits. Using the daily uncertainties, the local-spatial and spatial-temporal uncertainty (Ftemp) was obtained. The daily and mean emissions showed a variability structure that was described by spherical and Gaussian models. The differences between the daily maps were related to variations in the magnitude of FCO2, covering mean values ranging from 1.28 +/- 0.11 mu mol m(-2) s(-1) (F197) to 1.82 +/- 0.07 mu mol m(-2) s(-1) (F195). The Ftemp showed low spatial uncertainty coupled with high local uncertainty estimates. The average emission showed great spatial uncertainty of the simulated values. The evaluation of uncertainties associated with the knowledge of temporal and spatial variability is an important tool for understanding many phenomena over time, such as the quantification of greenhouse gases or the identification of areas with high crop productivity.
  • Authors:
    • Yeh, S.
    • Yui, S.
  • Source: Environmental Research Letters
  • Volume: 8
  • Issue: 4
  • Year: 2013
  • Summary: Brazil aims to increase palm oil production to meet the growing national and global demand for edible oil and biodiesel while preserving environmentally and culturally significant areas. As land use change (LUC) is the result of complex interactions between socio-economic and biophysical drivers operating at multiple temporal and spatial scales, the type and location of LUC depend on drivers such as neighboring land use, conversion elasticity, access to infrastructure, distance to markets, and land suitability. The purpose of this study is to develop scenarios to measure the impact of land conversion under three different enforcement scenarios (none, some, and strict enforcement). We found that converting 22.5 million hectares of land can produce approximately 29 billion gallons (110 billion liters) of biodiesel a year. Of that, 22-71% of the area can come from forest land, conservation units, wetland and indigenous areas, emitting 14-84 gCO(2)e MJ(-1). This direct land use emission alone can be higher than the carbon intensity of diesel that it intends to displace for lowering greenhouse gas emissions. This letter focuses narrowly on GHG emissions and does not address socio-economic-ecological prospects for these degraded lands for palm oil or for other purposes. Future studies should carefully evaluate these tradeoffs.
  • Authors:
    • Pellegrino, G. Q.
    • Assad, E. D.
    • Royce, F.
    • Singels, A.
    • Jones, J. W.
    • Marin, F. R.
    • Justino, F.
  • Source: CLIMATIC CHANGE
  • Volume: 117
  • Issue: 1-2
  • Year: 2013
  • Summary: This study evaluated the effects of climate change on sugarcane yield, water use efficiency, and irrigation needs in southern Brazil, based on downscaled outputs of two general circulation models (PRECIS and CSIRO) and a sugarcane growth model. For three harvest cycles every year, the DSSAT/CANEGRO model was used to simulate the baseline and four future climate scenarios for stalk yield for the 2050s. The model was calibrated for the main cultivar currently grown in Brazil based on five field experiments under several soil and climate conditions. The sensitivity of simulated stalk fresh mass (SFM) to air temperature, CO2 concentration [CO2] and rainfall was also analyzed. Simulated SFM responses to [CO2], air temperature and rainfall variations were consistent with the literature. There were increases in simulated SFM and water usage efficiency (WUE) for all scenarios. On average, for the current sugarcane area in the State of Sao Paulo, SFM would increase 24 % and WUE 34 % for rainfed sugarcane. The WUE rise is relevant because of the current concern about water supply in southern Brazil. Considering the current technological improvement rate, projected yields for 2050 ranged from 96 to 129 tha(-1), which are respectively 15 and 59 % higher than the current state average yield.
  • Authors:
    • da Silva, P. B.
    • Wendling, B.
    • Cardoso, M. M.
    • Kondo, M. K.
    • Brant Albuquerque, C. J.
  • Source: Bioscience Journal
  • Volume: 28
  • Issue: 1
  • Year: 2012
  • Summary: The objective of this work was evaluated the physical attributes of soil and the main agronomic characteristics of sorghum for grain in no-tillage under different vegetation cover. The experiment was conducted during two growing seasons. In the first years were sown seven grass species in intercropping with sorghum for pasture establishment and the sorghum single defining the eight treatments. In the second season, when direct sowing of sorghum, forages available in the trial were previously desiccated for no-till sorghum. The areas representing the tillage had been barred again. In relation to soil physical properties, experiments were conducted under a randomized block design in factorial 8 (treatments) x 3 (depths) with four replications. Data related to the agronomic characteristics of the sorghum experiment was conducted in a randomized block design with four replications. It concluded with the work that the various forages used in the formation of vegetation for no-tillage affects both soil physical properties such as grain yield of sorghum.