LA SCALA JUNIOR, N.

MARQUES JUNIOR, J.

MARTIN-NETO, L.

MILORI, D. M. B. P.

PANOSSO, A. R.

RCAAP - Repositório Científico de Acesso Aberto de Portugal

Correlations between soil respiration and soil properties in sugarcane areas under green and slash-and-burn management systems.

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EGU20 1O - EGU20 1OWebstreaming http://meetings.copernicus.orglegu201 0/informationlegu20 10_ webst...EGU2010 WebstreamingAs in previous years, selected presentations during the General Assembly will be Iive-streamed and are also available on demandafter the conference. Please enter the official EGU Webstreaming site. The 2010 programme includes:Press ConferencesAli press conferences will be streamed. Please visit the EGU Media Portal for further schedule information.Tuesday, 4 May 2010 I Great Debate• To what extent do humans impact the Earth's climate? 112:15-13:15Wednesday, 5 May 2010 I Union Award Presentations and Medal Lectures• Welcome/lntroduction 113:30• Farewell Session for Ame K. Richter 113:35• Union Medal & Award Ceremony 115:30• Gerhard Haerendel- Fascinating Plasma Structures (Jean Dominique Cassini Medal Lecture) 116:15• Roland von Huene - Subduction Zone Concepts and the 2010 Chile Earthqake (Arthur Holmes Medal Lecture) 117:00• Carlos A. Nobre - The Fate ofthe Amazon Forest in the 21st Century (Alexander von Humboldt Medal Lecture) 117:45• Jean-Yves Parlange - Wetting Front Instability in Porous Media (Alfred Wegener Medal Lecture) 118:30Thursday, 6 May 2010 I Great Debate• Getting real about energy 115:30-17:151 de 1 16/11/201010:35Geophysical Research AbstractsVol. 12, EGU201O-5983, 2010EGU General Assembly 20 10© Author(s) 2010Correlations between soil respiration and soil properties in sugarcaneareas under green and slash-and-burn management systemsAlan Rodrigo Panosso (I), Débora M. B. P. Milori (2), José Marques Júnior (1), Ladislau Martin-Neto (2), andNewton La Scala Jr. (I)(I) FCAV/UNESP. Via de Acesso Prof. Paulo Donato Castellane s/n, Jaboticabal, SP, Brazil (lascala@fcav.unesp.br), (2)CNPDINEMBRAPA. Rua XV de Novembro 1452,São Carlos, SP, BrazilSoil management causes changes in soil physical, chemical, and biological properties that consequently affect itsC02 emission. In this work we studied soil respiration (FC02) in areas with sugarcane production in southemBrazil under two different sugarcane management systems: green (G), consisting of mechanized harvesting thatproduces a large amount of crop residues left on the soil surface, and slash-and-burn (SB), in which the residuesare bumed before manual harvest, leaving no residues on the soil surface. The study was conducted after the har-vest period in two side-by-side grids installed in adjacent areas, having 20 measurement points each. The objectiveof this work was to determinate whether soil physical and chemical properties within each plot were useful inorder to explain the spatial variability of FC02, supposedly influence by each management system. Most of thesoil physical properties studied showed no significant differences between management systerns, but on the otherhand most 01' the chemical properties differed significantly when SB and G areas were compared. Total FC02was 31% higher in the SB plot (729 g C02 m-2) when compared to the G plot (557 g C02 m-2) throughout the70-day period after harvest studied. This seems to be related to the sensitivity of FC02 to precipitation events, asrespiration in this plot increased significantly with increases in soil moisture. Despite temporal variability showedto be positively related to soil moisture, inside each management system there was a negative correlation (p<O.Ol)between the spatial changes of FC02 and soil moisture (MS), R= -0.56 and -0.59 for G and SB respectively. Therewas no spatial correlation between FC02 and soi! organic matter in each management system, however, the hu-mification index (Hum) of organic rnauer was negatively linear correlated with FC02 in SB (R= -0.53, p<0.05)while positively linear correlated in G area (R=0.42, p<0.10). The multiple regression model analysis applied ineach management system indicates that 63% of the FC02 spatial variability in G managed could be explained bythe model: FC02(G)= 4.11978 -0.07672MS + 0.0045Hum +1.5352K -0.04474FWP, where K and FWP are potas-sium content and free water porosity in G area, respectively. On the other hand, 75% of FC02 spatial variabilityin SB managed plot was accounted by the model: FC02(SB) = 10.66774 -0.08624MS -0.02904Hum -2.42548K.Therefore, soil moisture, humification index of organic matter and potassium levei were the main propcrties able toexplain the spatial variability of FC02 in both sugarcane management systems. This result indicates that changesin sugarcane management systems could result in changes on the soil chemical properties, mostly, especially hu-mification index 01' organic matter. It seems that in conversion Irorn slash-and-bum to green harvest system, freewater porosity tums to be an important aspect in order to explain part of FC02 spatial variability in green managedsystem.

Correlations between soil respiration and soil properties in sugarcane areas under green and slash-and-burn management systems.

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RCAAP - Repositório Científico de Acesso Aberto de Portugal

Repository Open Access to Scientific Information from Embrapa