摘要
在室内恒温(20℃)培养,间歇破坏性采样(于培养后第2、6、13、20、27、41、55天采样)的条件下,研究蚯蚓活动对土壤中氮素矿化特征的影响。共设置4个处理:(1)对照处理-不接种蚯蚓不添加秸秆(S);(2)仅接种蚯蚓不添加秸秆处理(E);(3)不接种蚯蚓仅添加秸秆处理(O);(4)接种蚯蚓并添加秸秆处理(0E)。结果表明:在整个培养时期中,仅接种蚯蚓处理(E)的土壤铵态氮和硝态氮含量均较对照处理(S)有显著提高(P〈0.05),分别较同期对照处理(S)高出0.54-5.71倍和0.04-2.01倍;接种蚯蚓添加秸秆处理(OE)的土壤中的铵态氮含量较同期仅添加秸秆处理(0)增高了0.42-7.26倍,并达到显著性差异(P〈0.05),但两处理的硝态氮含量无显著性差异(P〉0.05)。从整体水平来看,无论是否添加秸秆,接种蚯蚓处理(E,OE)的土壤矿质氮水平均较相应的对照处理(S,O)有显著提高(P〈0.05),到培养55d时,分别增加了1.93倍和2.36倍。仅接种蚯蚓处理(E)的土壤氮素矿化速率和累积矿化速率较对照处理(S)有显著提高(P〈0.05);添加秸秆后,无论是否接种蚯蚓,土壤累积矿化速率均为负值,表现为对土壤矿质氮的净固定,而从土壤氮素矿化速率的变化来看,前期的各个时间段中主要表现为矿质氮的净固定,后期逐渐表现为一定程度的矿化。此外,仅接种蚯蚓处理(E)的全氮含量除了培养2d外,其他培养时期均与对照处理(S)有显著差异(P〈0.05),到培养55d时,其全氮含量较同期对照处理(S)增高了6.55%。相关性分析结果表明,在仅接种蚯蚓处理(E)中,培养前后蚯蚓鲜重的减少量与土壤全氮含量之间存在极显著正相关(P〈0.01),根据一元线性方程将蚯蚓损失的鲜重换算为蚯蚓体损失的氮量后发现,在整个培养期中蚯蚓体本身排泄的氮大约占土壤全氮含量增加量的百分比为42%-100%。
Effects of earthworms on soil nitrogen mineralization were studied in laboratory. Soil samples were destructively collected periodically on D2, D6, D13, D20, 1927, D41, and D55 after incubation. Four treatments were designed: (1) soil without earthworms or straw-control treatment (S); (2) soil only with earthworms (E); (3) soil only with straw (O); and (4) soilwith earthworms and straw (OE). Results indicated that throughout the entire incubation period, only Treatment Ewas significantly higher than Treatment S( p 〈 0.05)in both NH4^+ -N and NO3^- -N, by about 0.54 - 5.71 and 0.04 - 2.01 times separately. Compared with Treatment O, Treatment OE was much higher (p 〈 0.05) in content of soil NH4^+ -N, by about 0.42 - 7.26 times, but was more or less similar (p 〉 0.05) in content of soil NO3^- -N. Whether the straw was used or not, Treatments E and OE were significantly higher, or 1.93 and 2.36 times higher than Treatments S and O in content of mineral nitrogen (NH4^+ -N + NO3^- -N), respectively, after 55 days of incubation. The soil nitrogen mineralization rate and cumulative nitrogen mineralization rate in Treatment E increased significantly (p 〈 0.05) over Treatment S; In Treatments O and OE, whether earthworms were introduced or not, the cumulative nitrogen mineralization rates were below zero, represented as net immobilization of soil mineral nitrogen, and change in nitrogen mineralization rate showed net immobilization in the early phase, and certain mineralization in the late phase. The content of total nitrogen in Treatment E was significantly higher(p 〈 0.05)than in Treatment S in all the incubation phases except for in the first 2 days of incubation and at the end of the experiment, it was about 6.55 % higher. Besides that, significant positive correlation(p 〈 0.01 )was observed between soil total nitrogen content and decrement of earthworms in fresh weight. When the loss of earthworms in fresh weight was converted into the loss of nitrogen through earthworms with the simple liner equation, it was found that the nitrogen excreted by earthworms accounted for about 42% - 100% of the increment of soil total nitrogen.
出处
《土壤学报》
CAS
CSCD
北大核心
2007年第1期98-105,共8页
Acta Pedologica Sinica
基金
国家自然科学基金项目(30370286)
关键词
蚯蚓
矿质氮
氮素矿化速率
Earthworms
Mineral nitrogen
Nitrogen mineralization rate