Agriculture Reference
In-Depth Information
of some of the techniques and management
practices that have been applied strategic-
ally in India in arable lands with high car-
bon potential.
and use of agricultural residues and livestock
manure. Agroecological practices in conjunc-
tion with active organic matter amendments
could bring about a synergy and enhance sig-
nificantly the provision of ecosystem services
and increase in food production globally, as
illustrated by the African experience, where
millions of farmers have doubled their yield
following such practices.
'Subsidizing carbon' and closing
the resource loop
Organic matter plays a catalysing role for
soil structure, nutrient turnover and other
soil functions. The fundamental strategy of
restoring soil functions is based on agroeco-
logical land-care practices that entail car-
bon additions. These additions can be either
through aboveground vegetation (crop-pasture
rotation, cover crops, intercropping, etc.) or
through inputs from elsewhere, such as
urban and industrial organic waste. Typic-
ally, soil ecosystems are restored naturally
unless they have passed a degradation tip-
ping point. However, this process can take
decades (Zach et al ., 2006; Quiroga et al .,
2009) or centuries (Nikolaidis, 2011). Re-
versing the degradation trend and enhan-
cing soil ecosystem services requires signifi-
cantly more organic matter additions in the
short term compared to natural to long-term
restoration conditions, and in most of the
cases this process of restoration does not
reach the original level of carbon stocks
(Zach et al ., 2006).
A significant increase in the demand
for quantities of organic matter as a soil sup-
plement makes the need for organic matter/
nutrient recycling an urgent priority. It can
also help to reduce resource demand for in-
organic fertilizer sources for nitrogen and
phosphorus (De Schutter and Vanloqueren,
2011), as the cost of nitrogen fertilizers -
which is tied to energy prices for their pro-
duction and security - is rising and global
phosphate rock reserves are diminishing
(Cordell et al ., 2009; UNEP, 2011a). The glo-
bal demand for organic matter additions
will require a concerted effort in recycling
and closing of the nutrient resource loop;
for example, between urban areas and
peri-urban areas. It will also require organic
matter separation at the waste sources, com-
posting of municipal solid wastes and the
use of biosolids, as well as the collection
Sustainably closing the yield gap
The 'yield gap' is the difference between the
theoretical plant physiological maxima for
production in the absence of environmental
limitations and that which is achieved with
the help of currently used technology. Cur-
rent, climate-adjusted yields are all simi-
larly in the order of 60% of the theoretical
maxima for rice in South-east Asia, rain-fed
wheat in central Asia and rain-fed cereals in
Argentina and Brazil (Godfray et al ., 2010).
The yield gap is a factor in meeting the
world demand for food, which is projected
to double by 2050. The actual projected de-
mand for additional food is somewhat less
than double, because currently some 30-
40% of food in both developed and devel-
oping economies is lost to waste. It is as-
sumed that efforts to reduce waste will
become an important factor contributing to
meeting the projected demand for food
(Godfray et al ., 2010).
Improved crop and livestock manage-
ment are needed to address food security
issues and restore soil carbon. In doing so,
there are multiple synergistic benefits: (i)
the benefit of enhanced nutrient supply to
crop plants; (ii) improved water use and
water quality management; (iii) energy
and carbon inputs to support soil biodiver-
sity; (iv) the buffering role to help mitigate
the negative impacts of fluctuations in en-
vironmental conditions such as extreme
weather events and pest infestations; (v)
reduced soil erosion; and (vi) the co-benefit
of storing carbon, thereby sequestering CO 2
from the atmosphere (Bhattacharyya et al .,
2004).
The potential for reduced benefits
from soil carbon loss during (marginal)
 
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