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Table 1. Some examples of soil as sink of atmospheric CO 2 through adoption of best management practices

Region/Practice/Land use Parameter Impact Reference
Antarctica Global warming Soil C stock increased from 359 to 686 Pg De Mello et al. [19]
Film mulching and straw incorporation increased
Biodegradable Film Mulching SOC content and GHG emissions Qian et al. [20]
SOC content in 0-20 cm layer by 17.6% in 5 years
Brazil (Ferrasol) SOC sequestration by CA CA reduced GWP by SOC sequestration Piva et al. [21]
Drylands Irrigated land CA with residue retention Jin et al. [22]
May improve the sustainability of irrigated
Drylands CA and crop diversification Ghimire et al. [23]
systems
Microorganisms (B subtilis, strain MPI) may
Global Silicate weathering promote weathering to sequester Timmerman et al. [24]
2.02 Mg SIC/ha/year
Global Biochar: GHG emissions Significantly reduced emissions Fan et al. [25]
Global Biochar It is a negative emission technology Smith [26]
Biochar: swine-digestate-manure As an amendment to reduce emissions and Ayaz et al. [27]
Global
derived biochar improve nutrient use Elkhlifi et al. [28]
Conversion of conventional till to The effect of CA is site-specific as it is in poorly
Global Page et al. [29]
no-till (CA) drained soils where N 2 0 emission is increased
Global Irrigated carbonaceous soils
Annual DIC leaching in irrigated It may represent 2%-5% if the total annual CO 2 Schindlbacher et
Global
soils loss al. [30]
Crop residue return, rather than tillage or no-till
Global Input of C residues practice, is the most important factor influencing Fan et al. [31]
SOC sequestration and GHG emissions
Irrigation with wastewater may reduce use of N
Grasslands Wastewater use fertilizer and water from aquifers but the amount Fernández et al. [32]
applied should be limited
Appropriate production systems can sequester
India Dryland soils Srinivasarao et al. [33]
soil C
Adoption of CA with cover crop, residue retention
Pakistan Soil C sequestration Nazir et al. [34]
can store C
Manuring increased SOC and compensated for
Pakistan Organic farming Mohamad et al. [35]
higher GHG emissions

45% substitution (of organic in place of chemical fertilizers) may improve productivity and reduce N 2
emission.

Soil can be a sink of atmospheric CO when input of biomass C exceeds the losses by erosion, decomposition
2
and leaching. The strategy is to create a positive soil-C budget by choice of land use and soil management,
which increases the input of C in soil and reduces its losses. These practices which create a positive soil C
budget are called negative emission strategies or technologies . Of course, soil is akin to a bank account and
[17]
C is similar to money in a bank. The balance of C in soil, similar to money in a bank account, can be
increased via adoption of BMPs which cause more input of biomass C into soil than its removal by
decomposition and other degradative processes. Contrary to the bank account, however, soil C sequestration
may have an upper limit, also referred to as “soil carbon saturation” . Examples of some of these BMPs,
[18]
which strengthen soil C sink capacity, are discussed below. The data in Table 1 indicate a wide range of
site-specific BMPs which, by up-scaling and judicious use, can set in motion the processes that enhance soil
C stock and lead to adaptation and mitigation of ACC.

Choice of appropriate and site/soil-specific BMPs can sequester C and reduce GWP. Furthermore, the ACC
may also create some new sinks of atmospheric CO . De Mello et al. observed that ACC may change
[19]
2