科尔沁沙地30种植物叶凋落物CO2释放量及释放速率的研究

 采用可以有效控制环境因子的室内土壤培养试验，初步研究了科尔沁沙地30种植物叶凋落物的CO₂释放量及释放速率。结果表明：①在28 d培养期内，不同植物叶凋落物释放的CO₂量差异很大，其中，多年生植物叶凋落物CO₂释放量平均值大于一年生植物，但二者之间的差异不显著；禾本科植物叶凋落物CO₂释放量平均值明显小于其他植物，二者之间呈显著差异。②在28 d培养期内，不同植物叶凋落物每四天CO₂释放速率差异很大。一年生与多年生植物叶凋落物28 d内每四天释放CO₂的速率无显著差异；禾本科与其他植物叶凋落物每四天释放CO₂的速率在培养的前16 d差异呈显著，而后差异消失。③植物叶凋落物的全碳含量，氮含量，C／N，灰分/N及灰分含量不同造成CO₂释放量及释放速率的差异。叶凋落物28 d释放CO₂的量与叶凋落物初始碳含量及灰分含量均无相关关系，与叶凋落物初始氮含量呈显著正相关，与叶凋落物C／N及灰分／N呈显著负相关。叶凋落物培养期内每四天释放CO₂的速率与叶凋落物初始碳含量无相关关系；叶凋落物0_20天释放CO₂的速率与叶凋落物初始氮含量呈显著正相关，与叶凋落物C／N呈显著负相关；叶凋落物9_28天CO₂释放速率与灰分／N呈显著负相关；培养后期（17_28天）的CO₂释放速率与灰分含量呈显著负相关。

CO2 Release of the Decomposed Leaf Litters of 30 Species in Horqin Sand Land: in Relation to Litter Properties

CO₂ releases of the decomposed leaf litters of 30 species in Horqin Sand Land were measured with incubation method. The results showed that: ①The amount of CO₂ released from the decomposed leaf litters in the period of 28 day incubation was greatly different. The averaged CO₂ released amount of perennial leaf litters was greater than that of the annuals, but not significant, while the averaged CO₂ released amount of Gramineae was less than that of the other plants and significantly different. ②The rate of CO₂ released every four days was significantly different. The CO₂ release rate of Gramineae leaf litters was significantly different from that of the other plants in the first 16 days, and then the significance decreased, while the CO₂ release rate of the annual leaf litters was not significantly different from that of the perennials. ③The difference in C, N, C/N, Ash/N and Ash content of leaf litter was the major cause of the difference of CO₂ release amount and rate. CO₂ release amount of leaf litter was not significantly correlated to the initial carbon content and ash content of leaf litter in the 28 days, but positively correlated to the initial nitrogen content and negatively correlated to C／N and ash/N of leaf litters. CO₂ release rate of leaf litter was no correlation to the initial carbon content of leaf litters, if calculated every four days, but strongly and positively correlated to the initial content of nitrogen and strongly and negatively to C／N of leaf litters in the period of 0 to 20 days; CO₂ release rate was strongly and negatively correlated to the ash/N of leaf litters in the period of 9th to 28th day, and correlated negatively to ash content in the period from 17th to 28th.