Role of biochar in low carbon sustainable crop production of China: a synthesizing analysis of field studies
Abstract
BSA (BSA) has been proposed as a measure to enhance soil organic C sequestration and mitigate greenhouse gas emission from world croplands. In this study, results of BSA field experiments with rice paddy and dry croplands in 7 sites over China were synthesized for addressing an overall role of biochar in low carbon sustainable crop production. Soil amendment at rates of 0, 20 t ha-1 and 40 t ha-1 of biochar via pyrolysis from wheat straw at 35o-550°was performed consistently across the sites with local conventional fertilization and crop managements. Soil emission monitoring of non-CO2 greenhouse gases (CH4 and N2O) was conducted at 1 week interval during crop growing season in the year of BSA all sites and the subsequent year after BSA in some sites. Yield and properties, greenhouse gases (CH4 and N2O) and C intensity were assessed. The results from single experiments were synthesized for quantifying the relative changes in yield and GWP with BSA as well as changes in soil properties. BSA increased significantly soil pH, TN, SOC and decrease soil bulk density. On average, crop yield was significantly increased (~6% for rice and 10%~18% for maize) at an extent higher in croplands than in rice paddies. While BSA reduced slightly CH4 uptake in dry cropland, increases in CH4 emission showed a large uncertainty related to soil and climate condition as well as water regime from rice paddies. However,N2O emission from treated croplands were significantly reduced with BSA by 37~48% across sites. As the integration effect, global warming potential (GWP) and C intensity were decreased averagely by over 30% agriculture production (38% ~ 44% in dry cropland and 22% ~ 42% in paddy soil) with BSA, which was a great contribution to mitigation of CO2 in Chinese agriculture. The results further implicated BSA to cropland may to develop sustainable low carbon agriculture as a feasible measure. Key words: Biochar soil application, soil properties, C sequestration, CH4 and N2O mitigation, C intensity, synthesizing analysis
- Publication:
-
EGU General Assembly Conference Abstracts
- Pub Date:
- April 2013
- Bibcode:
- 2013EGUGA..15.1075Z