TITLE:
Assessing the Effects of Solarization and Sodium Azide Amendments on Selected Soil Parameters, Enzyme Activities and Microbial Populations
AUTHORS:
Anthony S. Kumi, Victor Khan, Ramble O. Ankumah
KEYWORDS:
Sodium Azide; Solarization; Methyl Bromide; Soil Enzyme Activity; Microbial Populations
JOURNAL NAME:
Journal of Environmental Protection,
Vol.4 No.8,
August
5,
2013
ABSTRACT: Soil borne pathogens result in serious
losses in yield of crops grown in the United States (US) and various parts of
the world. One of the most effective chemicals used to control these pathogens
was methyl bromide (CH3Br, MeBr), a pre-plant fumigant with a broad
spectrum of activity. Sodium azide has been proposed in combination with
solarization as a viable alternative to replace MeBr due to environmental
concerns with respect to ozone depletion in the stratosphere and as a possible
carcinogen. However, the possible impacts of sodium azide as a soil pollutant
and its effect on soil biological processes have not been fully studied. In
this study the effect of sodium azide used alone and in combination with
solarization and mulching on selected soil enzyme activities
(phosphomonoesterases, arylsulfatase and phosphodiesterase) were assessed.
Responses of arylsulfatase and phosphodiesterase to solarization and mulching
and azide treatment were found to be affected in the same way, suggesting a
similar mode of action. Soil pH in control soils was significantly increased by
azide application; however, in mulched soils, pH was decreased. The significant
decrease in soil pH in mulched soils may be very important in explaining the
increase in the acid phosphatase activity observed in mulched soils. Overall,
solarization and sodium azide treatment significantly reduced both fungi and
bacterial populations but the responses among the various treatments varied
significantly.