Impact of Some Pesticides on Total Counts of Soil Non-Symbiotic Nitrogen-Fixing Bacteria, Particularly Azotobacter sp

Nashmeel Saeed Khudhur and Abdul-ghany Omer Ismaeel Sarmamy
Department of Environmental Science, College of Science, University of Salahaddin, Kurdistan Region, Iraq
Department of Biology, College of Science, University of Salahaddin, Kurdistan Region, Iraq


A pot experiment was conducted to evaluate the effect of glyphosate herbicide (n-
phosphonomethyl glycine), mancozeb fungicide ([[1,2-ethanediylbis- [carbamodithioato]]
(2-)] manganese mixture with [[1,2-ethanediylbis- [carbamodithioato]]-(2- )] zinc) and
diazinon insecticide (O, O-diethyl O-[6- methyl-2- (1-methylethyl)- 4-pyrimidynyl]), three
soil orders and two soil moisture contents (50% and 100% of field capacity) and their
combinations on soil total non-symbiotic nitrogen-fixing bacteria particularly
Azotobacter sp. counts. This experiment last for two months from the 6 th of Jun until the
8 th of August 2011 with five sampling periods at biweekly intervals. Factorial experiment
(4×3×2) with Completely Randomized Design (CRD) and three replications was used
and the means were compared using Revised Least Significant Differences (R.LSD) at
the level of significant of 0.05. Significant results were obtained at the last two scheduled
period’s sampling of 4 th and 5 th , and the results showed that: Mancozeb fungicide
decreased total Azotobacter sp.; Diazinon insecticide decreased both total non-symbiotic
nitrogen-fixing bacteria and total Azotobacter sp.; Agholan soil (order Entisols) showed
the greatest increase in soil total non-symbiotic nitrogen-fixing bacteria. 50% soil
moisture content revealed the greatest reduction total Azotobacter sp. while, 100% soil
moisture content showed the greatest increase in soil total Azotobacter sp. count. The
combinations among: glyphosate, Agholan soil and 100% moisture combination showed
the greatest reduction in total non-symbiotic nitrogen-fixing bacteria and total
Azotobacter sp.

Key Words:
Soil pollution, Pesticides, Non-symbiotic, nitrogen-fixing bacteria, Azotobacter sp.


[1]Ellis, S. and A. Mellor. Soil and Environment. Routledge Publisher. Canada. (1995).  

[2]Sang-Jun Kim, B.S., M.S. Bioaugmentation for the remediation of pesticide contaminated soil with microorganisms directly enriched in soil or compost. Ph.D. Thesis, University of Ohio State. (2003).

[3]Jiang, J. and N. Wan. A model for ecological assessment to pesticide pollution management. Ecol. Modelling. 220(15): 1844-1851. (2009).

[4]Meyers, R.A. Encyclopedia of Analytical Chemistry: Applications, Theory and Instrumentation. John Wiley & Sons Ltd. 14484pp. (2008).

[5]Cycon, M; Z. Piotrowska-Seget and J. Kozdrój. Responses of indigenous microorganisms to a fungicidal mixture of mancozeb and dimethomorph added to sandy soils. Int. Biodeterio. Biodeg. 64: 316-323. (2010b).

[6]Pozo, C.; M.V. Martinez-Toledo; B. Rodelas and J. González-López. Response of soil microbiota to the addition of 3,3-diaminobenzidine. Appl. Soil Ecol. 23: 119-126. (2003).

[7]Gopal, M.; A. Gupta; V. Arunachalam and S.P. Magu. Impact of azadirachtin, an insecticidal allelochemical from neem on soil microflora, enzyme and respiratory activities. Bioreso. Technol. 98: 3154-3158. (2007).

[8]Ababutain, M.I.; F.N. Barakah and A.M. Heggo. Effect of pesticides (lannate and diazinon) on growth and activity of soil free living nitrogen fixing bacteria. J. Saudi Soc. Agric. Sci. 8 (1): 40-52. (2009).

[9]Hang, M.; C. Zhongyun; Z. Yuhua and C. Meichi. Effects of trifluralin on soil microbial populations and the nitrogen fixation activities. J. Environ. Sci. Health, Part B. 36(5): 569-579. (2001).

[10]USAID. Soil testing. Perennial Crop Support Series. Jalalabad, Afghanistan. Publication No. 2008-001-AFG. February 8. (2008). 

[11]Ryan, J.; Estefan, G. and Rashid, A. Soil and Plant Analysis Laboratory Manual. Second Edition. International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria. (2001).

[12]Pansu, M. and Gautheyrou, J. Handbook of Soil Analysis: Mineralogical, Organic and Inorganic Methods. Springer-Verlag Berlin Heidelberg. (2006).

[13]Bashour, I.I. and A.H. Sayegh. Methods of Analysis for Soils of Arid and Semi-Arid Regions. Food and Agriculture Organization of the United Nations, Rome. (2007).

[14]van Reeuwijk, L.P. Procedures for Soil Analysis, Technical Paper 9. Sixth Edition. International Soil Reference and Information Centre. The Netherlands. (2002).

[15]Hill, D.S. Pests of Crop in Warmer Climates and their Control. Springer Netherlands. XII Edition. (2008).

[16]Dashti, A.M. Isolation and characterization of Azotobacter spp. in Erbil soils, and study the effect of biofertilizers (Azotobacter chroococcum and transconjugant Lactobacillus plantarum) on nutrient uptake by wheat. Ph.D. Thesis, University of Salahaddin, Iraq. (2011).

[17]Atlas R.M. Handbook of Media for Environmental Microbiology. Second Edition. Taylor & Francis Group, LLC. New York. (2005).

[18]Pepper, I.L. and C.P. Gerba. Environmental Microbiology: A Laboratory Manual. Second Edition. Elsevier Academic Press. USA. (2004). 

[19]Scharlau, C. Handbook of Microbiological Culture Media. Sixth Edition. Spain. (2001).

[20]Feng, J.C. and D.G. Thompson. Fate of glyphosate in a Canadian forest watershed. 2. Persistence in foliage and soils. J. Agric. Food Chem. 38(4):118-1125. (1990).

[21]Gaines, T.A.; W. Zhang; D. Wang; B. Bukun; S.T. Chisholm; D.L. Shaner; S.J. Nissen; W.L. Patzoldt; P.J. Tranel; A.S. Culpepper; T.L. Grey; T.M. Webster; W.K. Vencill; R.D. Sammons; J. Jiang; C. Preston; J.E. Leach and P. Westra. Gene amplification confers glyphosate resistance in Amaranthus palmeri. Proceedings of the National Academy of Sciences of the United States of America. 107(3): 1029-1032. (2010).

[22]Roger, P.A.; I. Simpson; R. Oficialc; S. Ardales and R. Jimenez. Effects of pesticides on soil and water microflora and mesofauna in wetland ricefields: a summary of current knowledge and extrapolation to temperate environments. Australian J. Exp. Agric. 34: 1057-1068. (1994).  

[23]Barakah, F.N.; M.I. Ababutain and A.M. Heggo. Effect of lannate and diazinon pesticides on some soil microorganisms. Alexaneria Sci. Exch. J. 28(1): 38-53. (2007).

[24]McKinney, R.E. Environmental Pollution Control Microbiology. Marcel Dekker, Inc. 454pp. (2004).