IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Carbon stabilized into particulate organic matter in no-till corn and soybean systems is mostly derived from belowground biomass.
Autor/es:
MAZZILLI, S. R.; KEMANIAN, A.R.; ERNST, O.R.; JACKSON, R.B.; PIÑEIRO, G.
Revista:
SOIL BIOLOGY AND BIOCHEMISTRY
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2015
ISSN:
0038-0717
Resumen:
Quantifying the amount of carbon (C) incorporated from decomposing residues into soil organic carbon (CS) requires knowing the rate of C stabilization (humification rate) into different soil organic matter pools. However, the differential humification rate of C derived from belowground and aboveground biomass into CS pools has been poorly quantified. We estimated the contribution of aboveground and belowground biomass to the formation of CS in four agricultural treatments by measuring changes in δ13C natural abundance in particulate organic matter (CPOM) associated with manipulations of C3 and C4 biomass. The treatments were (1) continuous corn cropping (C4 plant), (2) continuous soybean cropping (C3), and two stubble exchange treatments (3 and 4) where the aboveground biomass left after the grain harvest was exchanged between corn and soybean plots, allowing the separation of aboveground and belowground C inputs to CS based on the different δ13C signatures. After two growing seasons, most of the new CPOM was primarily derived from belowground C inputs, even though they represented only ~10% of the total plant C inputs as residues. Belowground biomass contributed from 60% to almost 80% of the total new C present in the CPOM in the top 10 cm of soil. The humification rate of belowground C inputs into CPOM was 24% and 10%, while that of aboveground C inputs was only 0.5% and 1.0% for soybean and corn, respectively. Our results indicate that roots play a disproportionately important role in the CPOM budget in soils.