title: Comparison of neem or oregano with thiram on organic matter decomposition of a sand loam soil amended with compost, and on soil biological activity.
abstract: BACKGROUND
  Oregano essential oil and neem have been reported to be effective against soil-borne pathogens and nematodes. The possibility of having an effect on soil properties was the aim of this investigation. Moreover, thiram, a common widely used chemical pesticide, was used for comparison.
  
  
  RESULTS
  The effects of all three above-mentioned substances were investigated during an incubation experiment, for 15 weeks. Crushed neem pellets were added at 1.0, 2.0 or 3.0 g per 50 g of soil. Oregano dry matter was applied at 0.2, 0.4 or 0.6 g per 50 g of soil. Finally, thiram was applied at 0.1, 0.2 and 0.3 g per 50 g of soil. The addition of neem resulted in a decrease in organic carbon mineralisation, higher than that of oregano, but not as prominently as thiram. The addition of neem resulted in an increase in the content of nitrate, organic P, bioavailable P, bioavailable K and bioavailable Mn. Oregano had a slight negative effect on organic matter biodegradation, but caused an increase of nutritional mineral elements. Microbe colonies in soil were increased by the addition of neem cake granules, whereas oregano and thiram treatments caused a decrease. The addition of thiram reduced nitrate and available Mn contents, but at the lowest dose increased organic P and available K. Thiram reduced prominently available Cu at the upper rates, but it increased these forms at the lowest rate, while available Zn content was increased in two lowest rates.
  
  
  CONCLUSIONS
  The results of this study indicated that neem or oregano could be applied to the soil without any extremely negative effect on the available forms of nutritional mineral elements, as thiram does.
authors.affiliation: Department of Plant Production, Technological Education Institute of Larissa, 41110 Larissa, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Gougoulias
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vagelas
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vasilakoglou
authors.forename: Fotios
authors.initials: F
authors.lastname: Gravanis
authors.forename: Aida
authors.initials: A
authors.lastname: Louka
authors.forename: Eleni
authors.initials: E
authors.lastname: Wogiatzi
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Chouliaras
mesh_terms: D000890:Anti-Infective Agents; D031601:Azadirachta; D002244:Carbon; D008903:Minerals / Q000032:analysis*; D009566:Nitrates / Q000032:analysis; D009822:Oils, Volatile; D031341:Origanum; D010575:Pesticides; D028321:Plant Preparations; D012037:Refuse Disposal / Q000379:methods*; D012988:Soil Microbiology; D013893:Thiram; D014131:Trace Elements / Q000032:analysis
chemical_list: D000890:Anti-Infective Agents; D008903:Minerals; D009566:Nitrates; D009822:Oils, Volatile; D010575:Pesticides; D028321:Plant Preparations; D014131:Trace Elements; D013893:Thiram; D002244:Carbon