02390naa a2200313 a 450000100080000000500110000800800410001902400440006010000170010424501040012126000090022552015290023465000180176365000190178165000110180065000250181165000090183665000100184565300250185570000190188070000140189970000160191370000220192970000240195170000140197570000180198970000190200777300500202621448172022-07-19       2022    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1002/jeq2.203622DOI1 aVEECK, G. P.  aCO2 flux in a wheat-soybean succession in subtropical BrazilbA carbon sink.h[electronic resource]  c2022  aAbstract: The subtropical region of Brazil is home to 33% of the soybean [Glycine max (L.) Merr.] growing area and 90% of the wheat (Tritucum aestivum L.) growing area of this country. A soybean?wheat succession with fallow between crops is used in about 11% of the cultivated area. No study has quantified CO2 fluxes in annual soybean?wheat succession in this region. Hence, this study analyzed the seasonality of CO2 exchange (net ecosystem exchange [NEE]) in a 2015/2016 wheat?soybean succession in a commercial farm located in Carazinho, Rio Grande do Sul State, Brazil. The eddy covariance method was used to estimate the annual C balance of this system. The NEE was partitioned between gross primary productivity and ecosystem respiration to understand the dynamics of these fluxes during a year of wheat?soybean succession. Considering the net ecosystem balance between photosynthesis and respiration during the growing season, both soybean and wheat absorbed CO2 from the atmosphere (NEE wheat: ?347 ± 4 g C m?2; NEE soybean: ?242 ± 3 g C m?2). The fallow periods between growing seasons, however, acted as a source of 156 ± 2 g C m?2, reducing the C absorbed by the crops by 27%. For 1 yr, the net biome productivity was ?50 g C m?2 yr?1. The results obtained here demonstrate that the wheat?soybean succession was a net C sink under these specific climatic conditions and field management practices and that the long fallow period between crops limited the agroecosystem from becoming a more efficient CO2 sink.  aCultivo Anual  aManejo do Solo  aPousio  aRespiração do Solo  aSoja  aTrigo  aSucessão soja-trigo1 aDALMAGO, G. A.1 aBREMM, T.1 aBULIGON, L.1 aJACQUES, R. J. S.1 aFERNANDES, J. M. C.1 aSANTI, A.1 aVARGAS, P. R.1 aROBERTI, D. R.  tJournal of Environmental Quality, 1-17, 2022.