Increases of Temperature Response for CO2 Emission in a Biochar-Amended Vegetable Field Soil

To explore the effects of biochar application on CO 2 and CH 4 emission as well as the temperature response of CO 2 emission, an one-year experiment was conducted with three treatments (Control; CF, chemical fertilizer only; BCF, biochar combined with chemical fertilizer) in a vegetable field. Results shown that (1) compared with CF, short-term application of biochar significantly enhancing the cumulative CO 2 emission by 27.5% from soil-plant system, via increasing the soil microbial biomass (e.g., MBC) and C substrates (e.g., SOC). (2) A lowest emission of CH 4 was observed in BCF treatment, and an increase CH 4 consumption and reduce competition with NH 4 + may be responsible for the significant reduction in CH 4 source strength in biochar amended soil. (3) Activation energy ( E a ) was identified as an important factor influencing the temperature sensitivity ( Q 10 ) of CO 2 emission. Fertilization (CF and BCF) reduced the average Q 10 and E a values of CO 2 emission by 9.0-26.7% and 23.5-10.1%, relative to the control, respectively. Besides, the average of E a value in BCF treatment (51.9 KJ mol -1 ) was significantly higher than those in control and CF treatment. The increase in Q 10 and E a values following biochar application possibly contributed to the supplement of limit labile C and nutrient but highly resistant C following biochar application. Soil pH and crop cultivation may play key roles in influencing the change of E a . Our study concludes that biochar amendment increased CO 2 emission and temperature response of CO 2 emission from soil-plant system, while reduced CH 4 emission.