有机物添加对山西太岳山油松林土壤呼吸及碳组分的影响

The effect of organic matter addition on soil respiration and carbon component in Pinus tabuliformis forests in Taiyue Mountain, Shanxi Province, China

【目的】探讨添加不同类型有机物对油松林土壤有机碳组分及土壤呼吸的影响,为预测山西太岳山油松林生态系统中土壤的碳收支平衡提供参考。【方法】采用随机区组设计,以山西太岳山油松林地表的平均自然凋落物量为标准,向油松林地0~20 cm土壤中分别添加生物炭(BC)、玉米秸秆(JG)、辽东栎叶(LD)和油松叶(YS)等4种类型有机物,使用LI-8100 CO_(2)通量全自动测量系统对有机物添加条件下的土壤呼吸速率进行连续测定,并对各处理的土壤有机碳(SOC)、微生物生物量碳(MBC)、易氧化碳(ROC)、可溶性有机碳(DOC)含量进行监测,结合土壤呼吸与土壤有机碳及其组分之间的关系,探讨添加有机物对山西太岳山油松林土壤呼吸及碳组分的影响。【结果】(1)向土壤中添加BC显著降低了土壤呼吸速率,添加JG后土壤呼吸速率较CK显著提高了11.67%。,其余处理与CK差异不显著。在2014年7—11月和2015年5—10月,不同添加物处理间土壤呼吸速率从大至小表现为JG>LD>YS>CK。(2)有机物添加下土壤SOC含量随时间的增加有上升的趋势,在2014年8月,添加JG后显著提高了土壤SOC、MBC、ROC、DOC含量,添加BC显著提高了土壤MBC含量,添加LD和YS显著提高了土壤SOC和MBC含量。在2014年10月,添加JG显著提高了土壤SOC、MBC、ROC、DOC含量,添加LD显著提高了土壤MBC和ROC含量,添加YS显著提高了土壤SOC、MBC含量。在2015年3月,添加JG显著提高了土壤SOC、MBC和ROC含量,添加LD显著提高了土壤ROC含量。2015年5月,添加JG显著增加了土壤MBC含量。(3)与对照相比,添加BC后土温10℃时的土壤呼吸速率(R10)显著降低了18.01%,添加YS后R10显著增加了30.88%,添加其他有机物对温度敏感性系数(Q10)和R10没有显著影响。(4)土壤呼吸速率与土壤温度、SOC、MBC、ROC和DOC含量显著正相关。【结论】添加有机物显著影响土壤碳动态和土壤温湿度,这些都会对土壤CO_(2)排放产生显著影响,添加JG对土壤有机碳及其碳组分的提高效果最显著,但土壤呼吸速率最高,不利于碳的储存;添加LD可增加土壤活性有机碳含量,短期内可明显改善土壤有机碳库质量;添加BC可在短期内提高土壤微生物生物量碳含量,并显著降低土壤呼吸速率,减少土壤CO_(2)排放的效果最好。

【Objective】This research aims to investigate the effects of different organic matters on soil organic carbon and soil respiration in Pinus tabuliformis forest. The results can provide reference for predicting soil carbon budget of P. tabuliformis forest ecosystem in Taiyue Mountain, Shanxi Province, China.【Method】A random block design was used to add biochar(BC), maize straw(JG), Quercus mongolica leaf(LD) and P. tabuliformis leaf(YS) to 0-20 cm soil of P. tabuliformis forest in Taiyue Mountain, with no addition as control check(CK). Li-8100 automatic measurement system for CO_(2)flux was used to continuously measure soil respiration rate under organic matter addition, and the contents of soil organic carbon(SOC), microbial biomass carbon(MBC), readily oxidized carbon(ROC) and dissolved organic carbon(DOC) in each treatment were monitored. Based on the relationship between soil respiration and soil organic carbon and its components, the effects of organic matter addition on soil respiration and soil carbon components of P. tabuliformis forest in Taiyue Mountain were investigated.【Result】(1)The addition of biochar significantly reduced the soil respiration rate, and the soil respiration rate was significantly increased by 11.67% after adding JG compared with CK, while there was no significant difference between other treatments and CK.(2)In August 2014, the addition of JG significantly increased the soil SOC, MBC, ROC and DOC contents, the addition of BC significantly increased the soil MBC content, and the addition of LD and YS significantly increased the soil SOC and MBC contents. In October 2014, the addition of JG significantly increased soil SOC, MBC, ROC and DOC contents, the addition of LD significantly increased soil MBC and ROC contents, and the addition of YS significantly increased soil SOC and MBC contents. In March 2015, the addition of JG significantly increased soil SOC, MBC and ROC contents, while the addition of LD significantly increased soil ROC contents. In May 2015, JG supplementation significantly increased soil MBC content.(3) Compared with CK, soil respiration at 10(R10) was significantly decreased by 18.01% after BC addition, and increased by 30.88% after YS leaf addition. Other organic compounds had no significant effect on soil respiration temperature sensitivity(Q10) and R10.(4) Soil respiration rate was significantly positively correlated with soil temperature, SOC, MBC, ROC and DOC.【Conclusion】The addition of organic matter significantly affected soil carbon dynamics and soil temperature and humidity, which all had significant effects on soil CO_(2)emissions. The addition of JG had the most significant effect on soil organic carbon and its carbon components, but the soil respiration rate was the highest, which was not conducive to carbon storage. The addition of LD could increase soil active organic carbon content and significantly improve soil organic carbon pool quality in a short term, while the addition of BC could increase soil microbial biomass carbon content in a short term, and significantly reduce soil respiration rate, which has the best effect on reducing soil CO_(2)emission.