03825naa a2200637 a 450000100080000000500110000800800410001902200140006002400530007410000140012724501800014126000090032152019630033065000300229365000190232365000230234265000210236565000120238665000230239865000180242165000150243965000090245465000330246365000120249665000190250865000100252765000240253765000180256165000110257965000240259065000170261465000120263165000190264365000090266265300220267165300180269365300260271165300220273765300170275965300250277665300290280165300350283065300190286565300390288465300260292370000200294970000190296970000190298870000190300770000190302670000240304570000140306970000170308370000210310077300660312120017942021-07-06       2014    bl uuuu     u00u1 u    #d  a0378-42907 ahttp://dx.doi.org/10.1016/j.fcr.2014.03.0152DOI1 aBAYER, C.  aYield-scaled greenhouse gas emissions from flood irrigated rice under long-term conventional tillage and no-till systems in a Humid Subtropical climate.h[electronic resource]  c2014  aAbstract: Soils under flooded rice (Oryza sativa L.) production are one of the major anthropogenic source of CH4 emissions, an important greenhouse gas (GHG) with a 25-times larger global warming potential (GWP) than CO2. No-till systems (NT) systems may be a viable alternative to mitigate GHG emissions in comparison to conventional tillage (CT). The objectives of this study were to evaluate on a field scale the long-term effects of CT and NT systems on soil CH4 and N2O emissions, rice yields and yield-scaled emissions during five growing seasons (GS) in Southern Brazil. In addition, a short-term greenhouse experiment was conducted to isolate the effect of winter crop [ryegrass (Lolium multiflorum L.)] biomass incorporation on soil CH4 efflux. Averaged across years, the NT system resulted in 21% lower seasonal CH4 emissions than the CT system, at 408 and 517 kg CH4 ha-1 GS-1, respectively. No significant effect of tillage system on N2O emissions was observed. Methane emission was responsible for 96.5% of partial GWP (pGWP = CH4 × 25 + N2O × 298), stressing the importance of this GHG for developing low GHGs rice systems. No significant effect of tillage system on rice grain yields (average of 7.8 Mg ha-1 GS-1) was detected. Consequently, the NT system resulted in 23% lower yield-scaled pGWP, at 1.35 and 1.76 kg CO2eq kg-1 grain for NT and CT treatments, respectively. According to the greenhouse study, the incorporation of ryegrass biomass into the soil resulted in 2.8 times larger cumulative CH4 emission than the surface application of biomass, at 347.4 and 125.5 g CH4 m-2, respectively, due to higher dissolved organic carbon (DOC) concentration and reduced soil environment in subsurface soil layers. Our results indicate that biomass incorporation is the main cause of higher CH4 emissions from conventionally tilled soil and that NT system is a viable alternative to reduce yield-scaled GHG emissions from flooded rice fields.  aCarbon dioxide production  aClimate change  aFlooded conditions  agreenhouse gases  amethane  aMethane production  anitrous oxide  aNo-tillage  aRice  aSoil-atmosphere interactions  aTillage  aArroz inundado  aClima  aDióxido de carbono  aEfeito estufa  aMetano  aMudança climática  aOryza sativa  aPlantio  aPlantio direto  aSolo  aCambio climático  aCero labranza  aCondiciones inundadas  aCultivo del suelo  aFlooded rice  aGases de invernadero  aGlobal warming potential  aInteracciones suelo-atmósfera  aNo-till system  aProducción de dióxido de carbono  aProducción de metano1 aCOSTA, F. de S.1 aPEDROSO, G. M.1 aZSCHORNACK, T.1 aCAMARGO, E. S.1 aLIMA, M. A. de1 aFRIGHETTO, R. T. S.1 aGOMES, J.1 aMARCOLIN, E.1 aMACEDO, V. R. M.  tField Crops Research, Amsterdamgv. 162, p. 60-69, June 2014.