Author:
Silva-Olaya A. M.,Davies C. A.,Cerri C. E. P.,Allen D. J.,Mello F. F. C.,Cerri C. C.
Abstract
Expansion of sugarcane crop due to the increasing demand for sugar and ethanol can affect both existing soil carbon (C) stocks, and subsequent input of new C from above and belowground biomass, influencing the overall C intensity and C payback times due to the change of land use. We present above and belowground dry biomass production, shoot-to-root ratio (S:R) as well as the net annual C inputs to the soil for sugarcane in different ratoon stages. The selected areas were as follows: (1) recently planted sugarcane area (PC), (2) first year ratoon cane (RC1) and (3) 4-year ratoon cane (RC4), which were established under Typic Quartzipsamments located in north-eastern São Paulo State. The sugarcane S:R ratios ranged from 6.6 in PC to 3.4 in RC4, and total sugarcane C inputs from 29.6 to 30.8 Mg C ha–1. The overall C balance for land use change requires effects on soil C and also C inputs from previous and future land uses. The sugarcane C input was between 3.7 and 4.0 Mg C ha–1 for each sugarcane cycle of 5 years. When accounting for soil C stock changes and aboveground biomass C losses from the prior land use, the payback times for sugarcane biofuel C debts are reduced by 3, 2 and 1 years for Cerrado wooded, Cerrado grassland and pasture conversions into sugarcane respectively.
Subject
Earth-Surface Processes,Soil Science,Environmental Science (miscellaneous)
Cited by
8 articles.
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