Rice Production in Egypt: The Challenges of Climate Change …
301
materials in many countries. Agricultural lands worldwide suffer from the increment
of pest attacks and hardening of soil agglomerates because of the excessive fertilizer
application. This has led to enlarge the practice of applying straw return to the field
after harvesting, which has led to improve soil fertility, upgrade soil physical and
chemical properties, enhance crop yield, boost soil C sequestration, and mitigate
GHG emissions [14]. However, the farmers, to save time and labor, were used to
directly burn straw in fields, causing serious atmospheric problems [27]. It is stated
that utilizing of plant residues as mulch, instead of burning, has valuable effects for
refilling SOC, and returning to the soil of 1 Mg ha
−1 of rice, wheat, and maize straw
each year, thus sequestering about 130 kg C ha
−1 year
−1 [24]. It is reported that the
rates of rice residue inputs in rice production systems managed by farmers are variable, so the change of SOC in field experiments does not sufficiently represent the
actuality of C sequestration in paddy ecosystems. Therefore, it is important to know
more information about SOC responding to variation in C inputs due to changes in
paddy rice production [23].
5 Rice Fields as a Source of Greenhouse Gas (GHG)
Emissions
Climate change has been one of the main global environmental issues of the 21st
century, with increasing anthropogenic GHG emissions being the principal reason.
Nitrous oxide (N 2 O) and methane (CH 4 ) are the two significant GHGs, due to their
positive increases for radiative forcing and the permanence in the atmosphere, responsible for global warming, which contribute to shape the overall earth’s climate system
[14, 27, 28]. It is mentioned that agriculture is responsible for about 13% of annual
GHG emissions that are related to all human activities [29]. While, it is stated that
agriculture only contributes to approximately 20% of the current atmospheric GHG
concentrations, with methane (CH 4 ) and carbon dioxide (CO 2 ) as the two most effective carbon-containing GHGs released from agricultural activities [14]. However, it
is reported that approximately 50.1 GtCO 2 e GHG emissions were released from
anthropogenic sources in 2010 worldwide. Agriculture only accounts for approximately 5.0–5.8 GtCO 2 e (i.e. 10–12%) of these emissions. They also pointed to these
percentages only are the direct sources. If indirect sources are also taken into consideration, agriculture probably accounts for an additional 3–6% of the global emissions.
Modern intensive farming, which heavily depends on irrigation and chemical fertilizer application, is the largest source of CH 4 and nitrous oxide (N 2 O) emissions
[13, 30]. It is counted approximately 50% or more than 50% of the global anthropogenic emissions of N 2 O and CH 4 released from agricultural soils [27, 29]. While
it is reported that flooded-rice ecosystems accounted for approximately for 20% of
the total global CH 4 budget [31]. It is considered that edaphic condition and meteorological factor, in addition to agricultural management such as tillage, irrigation,
301
materials in many countries. Agricultural lands worldwide suffer from the increment
of pest attacks and hardening of soil agglomerates because of the excessive fertilizer
application. This has led to enlarge the practice of applying straw return to the field
after harvesting, which has led to improve soil fertility, upgrade soil physical and
chemical properties, enhance crop yield, boost soil C sequestration, and mitigate
GHG emissions [14]. However, the farmers, to save time and labor, were used to
directly burn straw in fields, causing serious atmospheric problems [27]. It is stated
that utilizing of plant residues as mulch, instead of burning, has valuable effects for
refilling SOC, and returning to the soil of 1 Mg ha
−1 of rice, wheat, and maize straw
each year, thus sequestering about 130 kg C ha
−1 year
−1 [24]. It is reported that the
rates of rice residue inputs in rice production systems managed by farmers are variable, so the change of SOC in field experiments does not sufficiently represent the
actuality of C sequestration in paddy ecosystems. Therefore, it is important to know
more information about SOC responding to variation in C inputs due to changes in
paddy rice production [23].
5 Rice Fields as a Source of Greenhouse Gas (GHG)
Emissions
Climate change has been one of the main global environmental issues of the 21st
century, with increasing anthropogenic GHG emissions being the principal reason.
Nitrous oxide (N 2 O) and methane (CH 4 ) are the two significant GHGs, due to their
positive increases for radiative forcing and the permanence in the atmosphere, responsible for global warming, which contribute to shape the overall earth’s climate system
[14, 27, 28]. It is mentioned that agriculture is responsible for about 13% of annual
GHG emissions that are related to all human activities [29]. While, it is stated that
agriculture only contributes to approximately 20% of the current atmospheric GHG
concentrations, with methane (CH 4 ) and carbon dioxide (CO 2 ) as the two most effective carbon-containing GHGs released from agricultural activities [14]. However, it
is reported that approximately 50.1 GtCO 2 e GHG emissions were released from
anthropogenic sources in 2010 worldwide. Agriculture only accounts for approximately 5.0–5.8 GtCO 2 e (i.e. 10–12%) of these emissions. They also pointed to these
percentages only are the direct sources. If indirect sources are also taken into consideration, agriculture probably accounts for an additional 3–6% of the global emissions.
Modern intensive farming, which heavily depends on irrigation and chemical fertilizer application, is the largest source of CH 4 and nitrous oxide (N 2 O) emissions
[13, 30]. It is counted approximately 50% or more than 50% of the global anthropogenic emissions of N 2 O and CH 4 released from agricultural soils [27, 29]. While
it is reported that flooded-rice ecosystems accounted for approximately for 20% of
the total global CH 4 budget [31]. It is considered that edaphic condition and meteorological factor, in addition to agricultural management such as tillage, irrigation,