ABSTRACT

Agronomic practices such as long-term use of plastic film mulching (PFM) and application of organic and inorganic fertilizers have profound effect on soil microbial community. However, there is limited information on the abundance and community structure of ammonia-oxidizers where these practices have been employed. In this study, we investigated soil ammonia oxidizers in a long-term application of fertilizer plots with or without PFM in two seasons of a maize-growing period. The fertilization treatments included: non-fertilizer control (CK), nitrogen fertilizer (N), organic manure (M), nitrogen fertilizer plus organic manure combined (MN). Real-time quantitative polymerase chain reaction (qPCR) of ammonia monooxygenase (amoA) genes revealed that the abundances of ammonia-oxidizing archaea (AOA) (1.0 x 10⁷ to 2.0 × 10¹¹ per copies g⁻¹ dry soil weight) significantly (p < 0.05) out-numbered ammonia-oxidizing bacteria (AOB) (5.0 x 10⁵ to 4.0 × 10⁹ copies g⁻¹ dry soil weight) abundances for June, July and October respectively. The phylogenetic analyses of denaturing gradient gel electrophoresis (DGGE) 16S rRNA gene revealed that AOB-uncultured Nitrosospira sp dominated bacterial ammonia oxidizers in fertilized and non-fertilized soils, regardless of PFM treatments for July and October. The non-fertilization treatment significantly increased bacterial richness (15.67 ± 0.33) under PFM treatment relative to fertilized treatments.

摘要

长期使用地膜覆盖（PFM）和施用有机和无机肥料等农艺实践对土壤微生物群落具有深远的影响。然而，关于采用这些做法的氨氧化剂的丰度和群落结构的信息有限。在这项研究中，我们调查了在玉米生长期的两个季节长期施用有或没有 PFM 的肥料地块中的土壤氨氧化剂。施肥处理包括：不施肥（CK）、氮肥（N）、有机肥（M）、氮肥加有机肥结合（MN）。氨单加氧酶 ( amoA ) 基因的实时定量聚合酶链反应 (qPCR)揭示了氨氧化古细菌 (AOA) (1.0 x 10⁷到 2.0 × 10 ¹¹每份 g ^-1干土重）显着（p < 0.05）数量超过氨氧化细菌（AOB）（5.0 x 10 ⁵到 4.0 × 10 ⁹份 g ^-1干土重）丰度分别为六月、七月和十月。变性梯度凝胶电泳 (DGGE) 16S rRNA 基因的系统发育分析表明，无论 7 月和 10 月的 PFM 处理如何，AOB 未培养的Nitrosospira sp 在施肥和未施肥的土壤中都占主导地位的细菌氨氧化剂。相对于受精处理，在 PFM 处理下，非施肥处理显着增加了细菌丰富度 (15.67 ± 0.33)。