Responses of active bacterial and fungal communities in soils under winter wheat to different fertilizer and pesticide regimens

Girvan, Martina S. and Bullimore, Juliet and Ball, Andrew S. and Pretty, Jules N. and Osborn, A. Mark (2004) Responses of active bacterial and fungal communities in soils under winter wheat to different fertilizer and pesticide regimens. Applied and Environmental Microbiology, 70 (5). pp. 2692-2701. ISSN 0099-2240

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Item Type:Article
Item Status:Live Archive

Abstract

The composition of the active microbial (bacterial and fungal) soil community in an arable wheat field subjected to different management practices was examined at five times during a 1-year period. Field sections were fertilized either at good agricultural practice (GAP) levels or at reduced levels (0.5 A GAP) and were with vesicular arbuscular mycorrhizae (VAM) at the same time. Field subsections were treated either with or without pesticides. Changes in the active microbial communities were investigated by denaturing gradient gel electrophoresis analysis of reverse transcription-PCR-amplified 16S and 18S rRNA. Microbial community structure was primarily determined by season, and the seasonal trends were similar for the fungal and bacterial components. Between-sample microbial heterogeneity decreased under a mature crop in the summer but increased following harvesting and plowing. Although similar overall trends were seen for the two microbial components, sample variability was greater for the fungal community than for the bacterial community. The greatest management effects were due to GAP fertilization, which caused increases in the bacterial numbers in the total and culturable communities. Microbial biomass similarly increased. GAP fertilization also caused large shifts in both the active bacterial community structure and the active fungal community structure and additionally resulted in a decrease in the heterogeneity of the active bacterial community. Pesticide addition did not significantly affect bacterial numbers or heterogeneity, but it led to major shifts in the active soil bacterial community structure. PCR primers specific for Glomales 25S rRNA genes were used to monitor the VAM population following inoculation. Glomales were detected initially only in VAM-inoculated field sections but were subsequently detected in noninoculated field sections as the season progressed. After plowing, the level of Glomales was reduced in noninoculated field sections but remained high in VAM-inoculated field sections. Inoculation of VAM correlated with elevated soil phosphate and carbon levels.

Keywords:Agriculture, Bacteria, Carbon, Crops, Fertilizers, Pesticides, Phosphates, RNA, Good agricultural practice (GAP), Inoculation, Soils, carbon, fertilizer, pesticide, phosphate, RNA 16S, RNA 18S, arbuscular mycorrhiza, fertilizer application, management practice, microbial community, pesticide, 25s rrna gene, agricultural management, agricultural procedures, arbuscular mycorrhiza, article, bacterial gene, fungus, Glomales, harvesting, microbial biomass, microflora, nonhuman, plowing, reverse transcription polymerase chain reaction, seasonal variation, soil microflora, soil pollution, summer, wheat, winter, Agriculture, Colony Count, Microbial, DNA, Ribosomal, Ecosystem, Electrophoresis, Fungi, Reverse Transcriptase Polymerase Chain Reaction, RNA, Ribosomal, 16S, RNA, Ribosomal, 18S, Soil Microbiology, Triticum, Bacteria (microorganisms), cellular organisms, Glomerales, Triticum aestivum
Subjects:C Biological Sciences > C180 Ecology
C Biological Sciences > C500 Microbiology
Divisions:College of Science > School of Life Sciences
ID Code:8960
Deposited On:22 Apr 2013 12:01

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