Soil Carbon Sequestration for Climate Change Mitigation …
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decomposed and transferred into the atmosphere by the diffusion process between
the surface soil and atmosphere [14].
Adoption of best management practices may make agricultural soils an effective
C sink because the C content of the soils is below the C saturation point, which means
that an equilibrium C content at which no extra additional C can be sequestered overtime under a steady C input. For example, fine-textured paddy soils are more efficient
for C sequestration when compared with dry soils; because of slow decomposition
rate of OC under submerged or anaerobic conditions over the cultivation season. Minimum or no tillage, cover cropping, the addition of organic amendments, balanced
fertilization, and rotational cropping are the most common used best management
practices to increase C sequestration in soils [19]. It is stated that in cropland, a
high level of SOC could be accomplished through appropriate methods such as crop
rotations, proper application rates for inorganic fertilizers and organic manures, conservation tillage methods, and integrated soil fertility management. Such enrichment
of the SOC stock will help in preserving good soil health for sustainable crop production as well as in managing global climate change [17]. However, soil C sequestration
relying on the traditional best management practices is not always effectual because
of loss of applied OC and native soil C loss because of soil disturbance by cultivation.
It is emphasized on that application of organic amendments in agricultural soils not
only improvs physical, chemical, and biological soil properties and decrease nutrients
leaching but also can mitigate GHGs emissions. They referred to biochar application
for this purpose. As well, applying balanced fertilization with synthetic fertilizer for
rice production, for example, may produce more rice plant residues, but residue incorporation may not necessarily enhance soil C sequestration because of such residues
are easily decomposed during cultivation. Also, green manure application among
organic nutrient sources, may not directly contribute to soil C sequestration because
of its faster decomposition rate. Although, application of livestock manure compost
which has recalcitrant C can enhance soil C sequestration; compost application may
decline rice crop due to its low nutrient availability. In this context, the application
of mineral amendments that have a high specific area, such as coal fly ash, along
with organic fertilizers as a source of nutrients can be effective to enhance soil C
sequestration via soil C stabilization [19–21].
Carbon sequestration in soils is typically expressed as the change in the total
carbon stock through the time. However, this method does not separate the fractions
of carbon that can be easily lost back to the atmosphere. For this reason, it is argued
that carbon sequestration should consider only the fraction that stays in the soil for
a long term. In this respect, soil C has been categorized into three stocks; active
(residence time 1–5 years), slow (20–40 years) and passive (400–2000 years) based
on their residence times [7]. Therefore, valuation the relative percentages of the
different C stocks along with C tracing using stable C isotopes has great promise
for better understanding of soil response to the changes in management or in the
climate. In this respect, it is emphasized that soil microbes act as a mediator in soil C
sequestration process because they are involved in most of the processes in C storage
and decomposition [22].
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decomposed and transferred into the atmosphere by the diffusion process between
the surface soil and atmosphere [14].
Adoption of best management practices may make agricultural soils an effective
C sink because the C content of the soils is below the C saturation point, which means
that an equilibrium C content at which no extra additional C can be sequestered overtime under a steady C input. For example, fine-textured paddy soils are more efficient
for C sequestration when compared with dry soils; because of slow decomposition
rate of OC under submerged or anaerobic conditions over the cultivation season. Minimum or no tillage, cover cropping, the addition of organic amendments, balanced
fertilization, and rotational cropping are the most common used best management
practices to increase C sequestration in soils [19]. It is stated that in cropland, a
high level of SOC could be accomplished through appropriate methods such as crop
rotations, proper application rates for inorganic fertilizers and organic manures, conservation tillage methods, and integrated soil fertility management. Such enrichment
of the SOC stock will help in preserving good soil health for sustainable crop production as well as in managing global climate change [17]. However, soil C sequestration
relying on the traditional best management practices is not always effectual because
of loss of applied OC and native soil C loss because of soil disturbance by cultivation.
It is emphasized on that application of organic amendments in agricultural soils not
only improvs physical, chemical, and biological soil properties and decrease nutrients
leaching but also can mitigate GHGs emissions. They referred to biochar application
for this purpose. As well, applying balanced fertilization with synthetic fertilizer for
rice production, for example, may produce more rice plant residues, but residue incorporation may not necessarily enhance soil C sequestration because of such residues
are easily decomposed during cultivation. Also, green manure application among
organic nutrient sources, may not directly contribute to soil C sequestration because
of its faster decomposition rate. Although, application of livestock manure compost
which has recalcitrant C can enhance soil C sequestration; compost application may
decline rice crop due to its low nutrient availability. In this context, the application
of mineral amendments that have a high specific area, such as coal fly ash, along
with organic fertilizers as a source of nutrients can be effective to enhance soil C
sequestration via soil C stabilization [19–21].
Carbon sequestration in soils is typically expressed as the change in the total
carbon stock through the time. However, this method does not separate the fractions
of carbon that can be easily lost back to the atmosphere. For this reason, it is argued
that carbon sequestration should consider only the fraction that stays in the soil for
a long term. In this respect, soil C has been categorized into three stocks; active
(residence time 1–5 years), slow (20–40 years) and passive (400–2000 years) based
on their residence times [7]. Therefore, valuation the relative percentages of the
different C stocks along with C tracing using stable C isotopes has great promise
for better understanding of soil response to the changes in management or in the
climate. In this respect, it is emphasized that soil microbes act as a mediator in soil C
sequestration process because they are involved in most of the processes in C storage
and decomposition [22].