Impacts of Land-use Change on Carbon Stocks and Dynamics in Central-southern South American Biomes: Cerrado, Atlantic Forest and Southern Grasslands - Soil Carbon: Science, Management and Policy for Multiple Benefits - page 249

Cerrados by ensuring long-term ground
cover, enhanced carbon fixation, increases
in soil organic matter content and reduction
in the emission of greenhouse gases, when
compared to conventional systems (Pacheco
et al ., 2012).
Long fallow periods and lower root
residue input to the soil imply that bio-
logical activity is concentrated at the soil
surface, which is more evident under NT,
and that deeper soil layers receive less or-
ganic matter inputs to maintain biological
functions. The consequences are well docu-
mented as an increase in bulk density, a de-
crease in infiltration rates and compaction
of soil at depths varying from 30 to 50 cm,
leading to increased runoff, erosion and wa-
terlogging. Maintaining good soil structure
throughout the soil profile requires a sus-
tained biological activity responsible for ag-
gregate formation and pore stabilization. An
approach to solve this problem for industri-
alized monocultures is using cover crops,
which are non-harvest crops grown during
the fallow interval to provide soil cover and
protection against wind and water erosion,
and providing an active rhizosphere to pro-
mote aggregate formation and carbon stor-
age. Preliminary studies in the semi-arid
and subhumid region of the Pampas have
shown that cover crops can provide signifi-
cant amounts of residue cover on the soil
surface, which in turn immobilizes nitrogen
and prevents its leaching into the ground-
water and that cover crops do not decrease
water availability to subsequent cash crops
(Fernández et al ., 2010).

the states of Mato Grosso do Sul and Goiás (Gal-
dos et al ., 2009; Angelini et al ., 2010; Rachid,
2010; Rachid et al ., 2012).
In the last decade, sugarcane plant-
ations for bioethanol and sugar production
have notably expanded in the Cerrado in
response to the rapidly growing demand
for biofuels and favoured by the suitable
topography, soil characteristics, water avail-
ability and climate, and by national pol-
icies (Manzatto et al ., 2009; Oosterveer and
Mol, 2010). Most of the sugarcane plant-
ations established in Brazil in recent years
replaced pastureland (approximately 65%
during the 2007/ 08 season), but also soy-
beans, orange and maize crops (together
27%) - food staples of global importance
(Gauder et al ., 2011). The result has been a
fast and steady expansion of sugarcane for
bioethanol and sugar production in the
Cerrados, mainly in the Brazilian states of
Mato Grosso do Sul and Goiás (INPE, 2011)
( Fig. 21.4) .
Most authors report a significant reduc-
tion in soil carbon and nitrogen stocks in
sugarcane plantations when compared with
native forests (Campos et al ., 2004; Resende
et al ., 2006; Pinheiro et al ., 2010; INPE,
2011). Campos et al . (2004), for example,
showed that 22 years after forest conversion
to pasture in the Atlantic Forest, 29% of the
SCSs were lost. On a neighbouring field
where a 10- year-old sugarcane field suc-
ceeded 12 years under pasture, SCS losses
increased to 43%, compared to that under
the native forest (as inferred by soils col-
lected from a neighbouring forest) ( Fig. 21.5) .
Some labile organic matter fractions,
such as microbial biomass and particulate
organic matter, have been shown to be sensi-
tive even to the slightest soil-quality change,
being good indicators of the ecosystem ser-
vices that are necessary for a sustainable
agricultural system, as demonstrated by
several authors (Graham and Haynes,
2006; Silva et al ., 2007; Galdos et al ., 2009;
Sant'Anna et al ., 2009; Souza et al ., 2012).
Souza et al . (2012) showed that native
vegetation and unburned sugarcane exhib-
ited qMic values (microbial quo-
tient = carbon on microbial biomass/total
organic carbon) of 2.64 and 2.84%, respectively,

Sugarcane Production and Impacts
on Carbon Stocks and Dynamics

Knowledge on the impacts of sugarcane oc-
cupation on soil attributes derives mainly
from research in the Atlantic Forest biome,
where most Brazilian sugarcane is culti-
vated (Campos et al ., 2001; Resende et al .,
2006; Balieiro et al ., 2008; Sant'Anna et al .,
2009; Pinheiro et al ., 2010), but some re-
search has been undertaken in the hotspot
sugarcane expansion areas of the Cerrados, in