Dissipation of chlorpyrifos in red loam soil and its effect on soil organisms
By: Rekha P R.
Contributor(s): Thomas George(Guide).
Material type:
BookPublisher: Vellayani Department of Soil Science and Agricultural Chemistry, College of Agriculture 2005Description: 71.DDC classification: 631.4 Online resources: Click here to access online Dissertation note: MSc Abstract: The persistence and degradation of chlorpyrifos, a contact insecticide, widely used for the control of soil inhabiting insects were studied in relation to the application of organic manure and lime and also its effect on soil organisms. The experiment was done in field plots at Instructional Farm, College of Agriculture, Vellayani.
The insecticide (chlorpyrifos 20 % EC) was applied @ 3 ml l-1 in different treatments. Soil samples were drawn 0, 5, 10, 20, 40 and 60 days after application and after the crop harvest. The residues were estimated in a gas liquid chromatograph using ECD.
The results showed that dissipation of chlorpyrifos followed a biphasic pattern with an initial phase of rapid dissipation followed by a phase of slow dissipation. Significant difference in dissipation was observed among different treatments. In the presence of lime chlorpyrifos was found to be highly unstable and dissipated easily by alkaline hydrolysis. Organic manure applied plots the persistence of chlorpyrifos was high due to the adsorption of insecticide in organic matter. The combined application of lime and organic manure cause significant difference in the degradation. The pattern of degradation of chlorpyrifos at lower depth of 15-30 cm soil were similar to surface layer except the initial survey of the insecticide at lower surface layer was less compared to upper layer (0-15 cm).
Application of chlorpyrifos inhibited the population of bacteria and arthropods, irrespective of the treatment. The bacterial population showed a significant decrease upto 10 days of application of chlorpyrifos and the original count was regained in 75 days. The result also showed that chlorpyrifos application did not affect fungal population. Chlorpyrifos was found to be highly toxic to soil arthropods upto 10 days of application and were not regained till 75 days of application. There was a slight decrease in nodulation in cowpea as compared to control. No residue of chlorpyrifos was detected in the plant parts (pods and grain) from any of the treatment after harvest. Nutrient content on the soil showed an increase in the analytical values due to the treatment effects.
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Theses
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KAU Central Library, Thrissur Theses | 631.4 REK/DI (Browse shelf) | Available | 172514 |
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MSc
The persistence and degradation of chlorpyrifos, a contact insecticide, widely used for the control of soil inhabiting insects were studied in relation to the application of organic manure and lime and also its effect on soil organisms. The experiment was done in field plots at Instructional Farm, College of Agriculture, Vellayani.
The insecticide (chlorpyrifos 20 % EC) was applied @ 3 ml l-1 in different treatments. Soil samples were drawn 0, 5, 10, 20, 40 and 60 days after application and after the crop harvest. The residues were estimated in a gas liquid chromatograph using ECD.
The results showed that dissipation of chlorpyrifos followed a biphasic pattern with an initial phase of rapid dissipation followed by a phase of slow dissipation. Significant difference in dissipation was observed among different treatments. In the presence of lime chlorpyrifos was found to be highly unstable and dissipated easily by alkaline hydrolysis. Organic manure applied plots the persistence of chlorpyrifos was high due to the adsorption of insecticide in organic matter. The combined application of lime and organic manure cause significant difference in the degradation. The pattern of degradation of chlorpyrifos at lower depth of 15-30 cm soil were similar to surface layer except the initial survey of the insecticide at lower surface layer was less compared to upper layer (0-15 cm).
Application of chlorpyrifos inhibited the population of bacteria and arthropods, irrespective of the treatment. The bacterial population showed a significant decrease upto 10 days of application of chlorpyrifos and the original count was regained in 75 days. The result also showed that chlorpyrifos application did not affect fungal population. Chlorpyrifos was found to be highly toxic to soil arthropods upto 10 days of application and were not regained till 75 days of application. There was a slight decrease in nodulation in cowpea as compared to control. No residue of chlorpyrifos was detected in the plant parts (pods and grain) from any of the treatment after harvest. Nutrient content on the soil showed an increase in the analytical values due to the treatment effects.
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