Study On Residues Rule And Degradation Dynamics Of Chlorothalonil In Acidified Black Soil

In the agricultural production process, in order to ensure excellent production and high-yield of crops, organic pesticides are widely used in agricultural production, caused a lot of pollution to agricultural products and the environment that hard to ignore. Chlorothalonil is a non-absorption of the broad-spectrum organochlorine fungicide that efficiency, been widely used in disease prevention and control of fruits, vegetables, crops and ornamental plants. Because the soil acidification is becoming more prominent, study the object of acidified black soil in this thesis, by changing the physical and chemical properties of acidified black soil, study the degradation dynamics and residual rules of chlorothalonil in the acidified black soil, analysis the environmental behavior of chlorothalonil in the soil, provide an important basis for guiding people speed up the removal of chlorothalonil residues in the acidified black soil through control the physical and chemical properties of soil, reduce the negative effects of chlorothalonil residues in the soil on the environment and poison the after the crop. Provide basic data and information for organic pollution chemistry and soil environmental chemistry.Research the residues rule of chlorothalonil with different initial concentrations in different water content (5%,10%,20%,30%) of acidified black soil. The results of chlorothalonil degradation speed in different water content soil showed that:20%>10%>30%>5%, The increase of water content to promote the chemical hydrolysis, conducive to the growth and metabolism of microbial, Accelerate the degradation rate of chlorothalonil. But when the soil moisture content is too high to exceed the field capacity of the soil, the poor soil aeration will inhibited the degradation of chlorothalonil.Research the residues rule of chlorothalonil with different initial concentrations in different pH values(4.2、5.2、6.0、7.2) of acidified black soil. The results of chlorothalonil degradation speed in different pH values soil showed that:7.2>6.0>5.2>4.2,At the process of pH change4to7,the biological activity of microorganisms increased with the pH value increased to reach the optimum pH value of the growth of microorganisms.Research the residues rule of chlorothalonil with different initial concentrations in different kinds of temperatures(10℃、20℃、30℃) of acidified black soil. The results of chlorothalonil degradation speed in different temperatures of acidified black soil showed that:30℃>20℃> 10℃, Because the temperature not only increasing the speed of chemical reaction, when the temperature rose from10℃to30℃, the temperature is getting closer to the optimum temperature of microbial growth, thereby the microbial degradation of chlorothalonil was increased in the soil.Research the residues rule of chlorothalonil with different initial concentrations in different organic matter content(30g/kg、40g/kg、50g/kg、60g/kg) of acidified black soil. The results of chlorothalonil degradation speed in different organic matter content of acidified black soil showed that:50g/kg>40g/kg>30g/kg≈60g/kg. Enhancement of soil organic matter within a certain range will provide the necessary nutrition for the growth of microbes, improve the efficiency of chlorothalonil microbial degradation. But organic matter in soil also adsorption the organic pesticides, it may affect the use of organic pesticides in the process of microbial growth and reproduction when organic matter is too high in soil, so the degradation rate of chlorothalonil slowed down when the soil organic matter content of60g/kg.Because application of different initial concentrations of chlorothalonil application in experiment, the results showed that, in the same soil environment, the chlorothalonil degradation rate slowed down with increasing initial concentrations of chlorothalonil. May be the chlorothalonil concentration is too high to inhibit the activity of soil microbial, reduced the microbial degradation of chlorothalonil.By changing the soil environment of the acidified black soil in field trials. Residues of chlorothalonil(The initial concentration is20mg/kg) in each treatment group after35days are8.03mg/kg(The soil moisture content is10%,Control group、4.12mg/kg(The soil moisture content is20%)、6.97mg/kg(The soil pH is7.1)、6.35mg/kg(The soil organic matter content is48g/kg)、4.85mg/kg(The soil temperature is30℃), Each group compared to controls, the degradation rates were increased:19.5%、5.3%、8.4%、15.9%;Obviously, all processing is conducive to the degradation of chlorothalonil in the acidified black soil...