Biochar production and application from crop straw had been proposed as one effective countermeasure
to mitigate climate change. We conducted a 2-year consecutive field experiment in 2009 and 2010 in rice
paddy to gain insight into the consistency over years of biochar effects on rice production and greenhouse
gases emissions. Biochar was amended in 2009 before rice transplanting at rates of 0, 10, 20 and 40 t ha−1,
soil emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were monitored with
closed chamber method at 7 days interval throughout the whole rice growing season (WRGS) both in
2009 and 2010. The results showed that biochar amendment increased rice productivity, soil pH, soil
organic carbon, total nitrogen but decreased soil bulk density in both cycles of rice growth. Soil respiration
observed no significant difference between biochar amendment and the corresponding control both in the
first and second cycle, respectively. However, biochar amendment decreased nitrous oxide emission but
increased methane emission in both cycles. No significant difference in carbon intensity of rice production
(GHGI) and global warming potential (GWP) were observed between the biochar amendment at the rate
of 10 t ha−1 and 40 t ha−1 and control though the GWP and GHGI was increased by 39% and 26% at the
rate of 20 t ha−1 respectively, in the first cycle. However, in the second cycle, both of overall GWP and
GHGI were observed significantly decreased under biochar amendment as compared to control, ranging
from 7.1% to 18.7% and from 12.4% to 34.8%, respectively. The biochar effect intensity on global warming
potential were observed from
−2.5% to 39.2% in the first cycle, and from
−18.7% to
−7.1% in the second
cycle. However, the biochar effect intensity on C intensity of rice production was observed from
−10.2%
to 25.8% in the first cycle, and from
−36.9% to
−18.6% in the second cycle. Therefore, biochar effect
on reducing the overall C intensity of rice production could become stronger in the subsequent cycles
than that in the first cycle though a consistently strong effect on reducing N2O emission in a single crop
cycle after biochar amendment. Nevertheless, these effects were not found in proportional to biochar
amendment rates and a high rice yield but lowest C intensity was achieved under biochar amendment
Biochar production and application from crop straw had been proposed as one effective countermeasure
to mitigate climate change. We conducted a 2-year consecutive field experiment in 2009 and 2010 in rice
paddy to gain insight into the consistency over years of biochar effects on rice production and greenhouse
gases emissions. Biochar was amended in 2009 before rice transplanting at rates of 0, 10, 20 and 40 t ha−1,
soil emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were monitored with
closed chamber method at 7 days interval throughout the whole rice growing season (WRGS) both in
2009 and 2010. The results showed that biochar amendment increased rice productivity, soil pH, soil
organic carbon, total nitrogen but decreased soil bulk density in both cycles of rice growth. Soil respiration
observed no significant difference between biochar amendment and the corresponding control both in the
first and second cycle, respectively. However, biochar amendment decreased nitrous oxide emission but
increased methane emission in both cycles. No significant difference in carbon intensity of rice production
(GHGI) and global warming potential (GWP) were observed between the biochar amendment at the rate
of 10 t ha−1 and 40 t ha−1 and control though the GWP and GHGI was increased by 39% and 26% at the
rate of 20 t ha−1 respectively, in the first cycle. However, in the second cycle, both of overall GWP and
GHGI were observed significantly decreased under biochar amendment as compared to control, ranging
from 7.1% to 18.7% and from 12.4% to 34.8%, respectively. The biochar effect intensity on global warming
potential were observed from
−2.5% to 39.2% in the first cycle, and from
−18.7% to
−7.1% in the second
cycle. However, the biochar effect intensity on C intensity of rice production was observed from
−10.2%
to 25.8% in the first cycle, and from
−36.9% to
−18.6% in the second cycle. Therefore, biochar effect
on reducing the overall C intensity of rice production could become stronger in the subsequent cycles
than that in the first cycle though a consistently strong effect on reducing N2O emission in a single crop
cycle after biochar amendment. Nevertheless, these effects were not found in proportional to biochar
amendment rates and a high rice yield but lowest C intensity was achieved under biochar amendment
การแปล กรุณารอสักครู่..