Biochar has unique physicochemical properties of being rich in carbon, being alkaline, and exhibiting a highly porous structure, which can adjust features of different systems. A 90-day microcosm incubation experiment was performed to investigate the effects of corn straw biochar on the process, properties, nutrient contents, and CO2 emissions during corn straw composting. There were four treatments, including control (CK), 5% biochar addition (B1, as mass fractions of biochar), 10% biochar addition (B2), and 20% biochar addition (B3). The results showed that biochar significantly increased the temperature rise rate and temperature peak of the straw maturation system, and promoted straw decomposition. Biochar increased the pH of the microbial active period, and the electrical conductivity (EC) value of the straw decomposition system, which provided a more suitable environment for microbial degradation of the organics. Further more, biochar decreased the organic matter content, increased the total nutrient content of the straw decomposition system, and improved the quality of the straw decomposition products. In addition, nitrogen (N) content was not changed by increasing amount of biochar; however, both phosphorus (P2O5) and potassium (K2O) content were significantly increased. Compared to control, the content of P2O5 and K2O in B3 treatment was increased by 0.2% and 0.9%, respectively. Biochar addition could improve CO2 emission of the straw decomposition system. The CO2 emission was consistent with the trend of temperature change, which provided solid evidence that biochar improve the degradation of organic matter by microbes in the system.
生物炭具有良好的理化特性(富碳、呈碱性、孔隙丰富),能够有效调节其所在系统的理化性质.通过室内培养试验研究了玉米秸秆生物炭对玉米秸秆腐熟进程以及腐熟产物的理化性质、养分含量和CO2气体排放的影响.试验设置4个处理:对照(CK);生物炭添加量5%(B1,生物炭干基质量占玉米秸秆腐熟体系的干基质量分数);生物炭添加量10%(B2);生物炭添加量20%(B3).结果表明: 生物炭能够提高秸秆腐熟体系的升温速率和温度峰值,加快秸秆腐熟进程;生物炭能够提高秸秆腐熟过程中微生物活跃时期的pH值,提高秸秆腐熟体系的电导率(EC),为微生物降解有机物提供更适宜的环境;生物炭能够促进秸秆腐熟体系有机质的降解,增加秸秆腐熟体系的总养分含量,提高秸秆腐熟产物的品质.另外,随着生物炭添加量的提高,氮(N)含量没有显著变化,磷(P2O5)含量和钾(K2O)含量都显著提高.其中,B3处理的P2O5和K2O含量较CK分别提高了0.2%和0.9%.生物炭添加能够提高秸秆腐熟体系CO2的排放通量,且CO2排放通量与温度的变化趋势一致,进一步说明生物炭能够提高微生物降解有机物的强度.
Keywords: CO 2 emission; biochar; nutrient content; straw decomposition.