Papers
The primary sources of carbon loss during the crop-establishment period in a subtropical Oxisol under contrasting tillage systems.
Author: Luciano Z. Pes, Telmo J.C. Amado, Newton La Scala Jr., Cimélio Bayer, Jackson E. Fiorin
Keywords: Soil-carbon stabilization, no-till, Aggregate disruption, Global warming, Carbon crop residue.
Summary
The CO 2 –C losses under CT were equivalent to 65% of the above ground C input by winter cover crops, whereas this value decrease d to 35% in NT. Exponential -decay modeling of the data for the first week showed that approximately 20% of the CO 2–C losses under CT were related to the expo sure of mineralizable resident soil C due by tillage operations. The analysis showed that this value de creased to only 2% for the three-week period. The CO 2–C emissions exhibited a positive linear relationship with soil temperature and soil water-fil led porosity under NT, but a similar relationship was found only with soil temperature under CT. For this Oxisol during the crop-establishment period, the physical aggregate disruption induced by long- term CT played a secondary role in CO2 –C losses relative to the recent crop -residue C input from tillage operations.