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1.
Assiut University Bulletin for Environmental Researches. 2015; 18 (1): 29-42
in Arabic | IMEMR | ID: emr-168235

ABSTRACT

This study aims to identify the effect of different concentrations of insecticides the common dorspan and decis on the total number of Nitrosomonas, Nitrobacter and cellulose degradation bacteria in the soil during the winter and spring of the agricultural season 2012/2013 has been selected for two insecticide fixed rates [half - the same - twice] concentration, was treated soil with two insecticide both individually and prescribed for each concentration of insecticide using spraying machine 10-liter, with a smaple treatmen without. Results insecticides showed its effect on bacterial groups, and has been associated it effect by quantity additive concentration, dropped the numbers of Nitrosomonas, Nitrobacter and cellulose degradation at twice and provided for it, that continued period of time after soil treatment to make sure their influence in general and not because of decline amount of the required nitrogen for the decompose of organic carbon, while it did not affect half concentration of two insecticides on the numbers of Nitrosomonas and degradation of cellulose bacteria, it returned to increase in recent weeks indicating the biodecomposition of insecticide and there is no inhibitory effect of this concentration on the two groups. For Nitrobacter, the numbers decreased in the half concentration of two insecticides in recent weeks after increase it in the first few weeks but dorspan returned to the increase in the last week which shows the cumulative effect of Decis, while dorspan decline the numbers by decreasing the amount of the insecticide and the occurrence of biodecomposition and there is no accumulative effect of this insecticides. Comparing insecticides show that the effect of high concentrations of two insecticides similar on the number of economically important groups, while differed effect the half concentration on Nitrobacter for Nitrosomonas and degradation of celluiose bacteria, which were similar in this concentration too Through statistical analysis shows that there is a highly significant of the interaction between the type of insecticide and concentration, and the insecticide depends on the concentration to show the impact on the numbers of Nitrification and cellulose degradation bacteria at the level of of significance 0.05


Subject(s)
Bacteria , Soil , Soil Microbiology , Nitriles , Pyrethrins , Nitrosomonas/drug effects , Nitrobacter/drug effects , Cellulose
2.
Assiut University Bulletin for Environmental Researches. 2015; 18 (1): 43-54
in Arabic | IMEMR | ID: emr-168236

ABSTRACT

This study aims to identify the effect of different concentrations of pesticides dorspan and decis locally common on the biomass of bacteria, fungi, and activity in the soil during the winter and spring growing seasons 2012 / 2013. Chosen constant rates of pesticides [half - the same - double] concentrations with samples used to treat the soil and then the results compared. For each sample and concentration a 10 liter spray machine was used. The results showed that in addition to pesticides decis and dorspan, the different concentrations used to eliminate agriculture insects had negative effects on vital composition of the soil and consequently also resulted in the inhibition of the process of release of carbon dioxide .These pesticides are not constant and are subject to decomposition by soil microorganisms and thus affect the numbers and activity in the soil. High concentrations of decis, resulted in decrease of the number of bacteria and fungi with time. Dorspan also showed a similar effect on the bacteria but less on the fungus. High concentration also influenced negatively rates of CO[2], may be due also to degradation of pesticide toxicity due to this decelerating rates of CO[2] release. This was noticed for all concentrations. After 2-4 weeks of the addition, the effect of concentrations resulted in higher proportion to the amount of CO[2] rebase, which was inversely related to pesticides concentration. Because the decomposition are vital in the long run, rise of release in the amount of CO[2] in the beginning may be more related to the decomposition of organic compounds present in the soil and not for ease of metabolism or use of these pesticides by soil microbes. Statistical analysis showed that there is a significant effect of the interaction between the type of pesticide and concentration at levels of significance 0.95 and 0.01


Subject(s)
Biomass , Soil , Bacteria , Fungi
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