大气CO_2升高和蚯蚓活动对土壤C、N的影响

Influence of earthworm on C & N content in soil under elevated CO_2

以加倍CO2浓度(750μmol/mol)处理和正常CO2浓度(370μmol/mol)生长下的棉花凋落叶为试验材料,以威廉腔蚓Metaphire guillemi(Michaelsen,1895)和不同的CO2浓度(750μmol/mol和370μmol/mol)为作用因子,分析了蚯蚓、CO2浓度通过叶片分解对土壤C、N含量的影响。结果表明:接种蚯蚓和加入凋落叶的联合作用对有机C有显著提高作用。接种蚯蚓对土壤全N含量影响不显著,但CO2浓度升高和蚯蚓联合作用对土壤全N含量有显著影响。CO2、叶片、蚯蚓3因子联合作用对土壤C、N含量有显著提高作用,且与蚯蚓和叶片联合作用对土壤C、N含量的影响相比,其效果更显著。结果显示,CO2浓度的升高通过改变植物凋落物C含量及其营养成分,影响了其潜在的降解有效性,同时大气CO2浓度的升高影响凋落物在蚯蚓体内降解过程,从而对凋落物的有效降解产生显著影响,最终改变土壤C、N含量。

The influence of earthworm and elevated CO2 on cotton leaf decomposition and C and N transformation in the soil by the 56 days experiment treated with earthworm under different levels of CO2 were analyzed. The effect of different levels of C02, cotton leaf and their interactions on C content in soil was not significant, while interaction of earthworm and cotton leaf was significant. Earthworm didn＇t influence the N content solely, but the combined effect of elevated CO2 and earthworm could influence the N content. The interaction of CO2 , earthworm and leaf was more significant than that of earthworm and leaf. Our results indicated that the elevated CO2 made the component of litter decomposition easier and improved the ability of decomposition and transformation of litter through earthworm, resulted in the change of C and N content in soil.