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| Dynamics and Interrelationship of CO2 Emissions and Dissolved Organic Carbon in Soils with Crop Residue Retention Under Different Tillage Practices |
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| KeyWord:crop residues retention; CO2 emission; dissolved organic carbon; tillage practice |
| Author Name | Affiliation | | QIN Yue | Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
University of Chinese Academy of Sciences, Beijing 100049, China | | LI Bin-bin | Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China | | WU Lan-fang | Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China |
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| Abstract: |
| Crop residue retention in soils usually enhances organic matter accumulation but may also increase CO2 emissions from soils. A long-term experiment was started in 2008. Four treatments were designed：plowing with residue retention（CT+）, plowing with residue removed（CT-）, no tillage with residue retention（NT+） and no-tillage with residue removed（NT-）. Emissions of CO2 from soils were evaluated by closed static chamber-gas chromatography method. Dissolved organic carbon（DOC） was measured during 2010—2011 and 2012—2013 wheat seasons. The CO2 emissions decreased from the sprout to the wintering stage，then increased from turning green stage, and reached peak values at flowering stage. The CO2 emissions in 2010—2011 and 2012-2013 wheat seasons were CT+：273.94 and 246.44 mg·m-2·h-1；CT-：212.57 and 183.54 mg·m-2·h-1；NT+：188.41 and 200.06 mg·m-2·h-1; and NT-：179.66 and 179.10 mg·m-2·h-1, respectively. During 2010—2011 and 2012—2013 wheat season, the average concentrations of DOC were CT+：0.601 and 0.467 g·kg-1; CT-：0.530 and 0.377 g·kg-1；NT+：0.621 and 0.544 g·kg-1; and NT-：0.528 and 0.402 g·kg-1, respectively. Crop residue retention significantly increased CO2 emissions, DOC and soil organic matter. Tillage significantly increased CO2 emission but had no effects on DOC and organic matter. No-tillage significantly decreased CO2 emissions and increased organic matter concentrations, but did not influence DOC. There was no significant correlation between CO2 emission and DOC. However, CO2 emissions and contents of organic matter were positively correlated. The concentrations of DOC and organic matter were not significantly correlated. |
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