蚯蚓对不同阔叶落叶的摄食作用

Earthworms' ingestion on different broad-leafed litters

采取室内试验,研究蚯蚓对红松阔叶混交林中几种不同阔叶的摄食量及影响因素、蚯蚓在不同阔叶中的生长状况和对有机碳和全氮的影响,探讨蚯蚓在东北红松阔叶混交林阔叶分解中的作用。蚯蚓喜食枫桦、紫椴和色木槭分解落叶,不喜食水曲柳分解落叶。试验表明,温度、凋落叶种类和凋落叶的分解时间等因素影响蚯蚓摄食量的大小。蚯蚓对3种喜食分解落叶摄食量平均值为:枫桦>色木槭>紫椴。不同温度条件下蚯蚓摄食量平均值为:20℃>25℃>15℃。凋落叶分解时间越长,蚯蚓越喜食,其摄食量也越大。分解落叶的C/N比新鲜凋落叶低。蚯蚓在3种凋落叶中的日增重倍数和日排粪量随着温度的升高而增加。不同温度下蚯蚓日增重倍数的平均值为25℃>20℃>15℃。蚯蚓在紫椴凋落叶中日增重倍数高于枫桦和色木槭分解落叶,在色木槭分解落叶的摄食过程中日排粪平均值高于紫椴和枫桦凋落叶。微生物对落叶中有机碳分解40d的作用小于蚯蚓对落叶摄食20d。蚯蚓摄食20d对增加凋落叶中的全氮含量的作用大于微生物单独分解40d。在凉水国家级自然保护区,蚯蚓对阔叶凋落叶的分解占年平均凋落叶量的10.3%左右。蚯蚓在红松阔叶混交林中阔叶分解中的作用不可忽视。

We studied the feeding preferences of earthworms from Pinus koraiensis mixed with broadleaf forest for various leaf litters. The effect of earthworms＇ feeding activity upon decomposition of broad-leafed litters in Pinus koraiensis mixed with broadleaf forest ecosystem was demonstrated. Betula costata, Tilia amurensis and Acer mono leaf litters were palatable for earthworms, while Fraxinus mandshurica leaf litters were not palatable for earthworms. Temperature, species of leaf and decomposition time influenced the feeding activity of earthworms. The order of preference of earthworms for different decomposed leaf litters was Betula costata 〉 Acer mono 〉 Tilia amurensis. The mean ingestion of earthworms at different temperatures was 20℃ 〉 25℃ 〉 15℃. Earthworms preferred decomposed litters to fresh ones. The longer the leaf litters had decomposed, the greater the amounts ingested. The value of C/N of composted leaf litter was lower than fresh litter. Daily weight increment and excreta increased with temperature. Daily weight increment of earthworms at different temperatures was 25℃ 〉 20℃ 〉 15℃. Daily weight increment of earthworms was highest in Tilia amurensis leaf litters. Daily excreta of earthworms in Acer mono leaf litters was higher than others. The decomposition of organic C in leaf litters by microbes for 40 d was smaller than ingestion of earthworms for 20 d. The incremental total N of leaf litters by ingestion of earthworms was bigger than microbes for 40 d. Earthworms ingest 10.3% of annual average broad-leafed litter in Liangshui national nature reserve. Earthworms exert important effects on broad-leafed litters in Pinus koraiensis broad-leafed mixed forest.