The Ecology Research Of Bacteria Degrading Organophosphate Pesticide-Omethoate In Farmland Ecosystem

From a farmland which used organophosphate pesticide omethoate as insecticide frequently, we gathered soil in spring , summer, autumn and winter , From the collection soil, isoloated the aerobic bacteria that can degradate organohosphate pesticide omethoate. After further purifing the isoloated bacteria, we classified and characterized them, according to their individual form, physiological and biochemical to characterize, characterize to bacteria genus. Calculated the total of aerobic bacteria in soil of each senson, the total of bacteria of degrading omethoate, as well as the percentage of each degradation bacteria genus, and measured the physico chemical nature of each seasonal soil sample. Through analysing, we attempt to know the degrading omethoate bacteria's development of seasonal growth and decline in this ecosystem. This farmland was weak acidic soil, and organic matter content is abundant, the organic matter content of summer soil was the most rich. The alterration of driness and wetness in soil was not frequenty. Kalium, phosphorus and nitrogen content were comparatively rich and wouldn't change much in four seasons. Among the tatol of soil bacteria, the summer's bacteria quantity was the most. Spring, autumn and winter were secondly respectively. On degradation bacteria quantity, the dgradation bacteria quantity in soil of summer was the most, spring , autumn and winter were secondly respectively. Between the content of phosphorus and the quantity degradation bacteria have no obrious correlation (r =0.494). The percentage of autumn degradation bacteria was the biggest, it was 0.547%. Among degradation bacteria genus, the bacillus proportion in each season was the biggest, that was 44.44%, 50.00%, 48.15% and 47.22% in spring, summer, autumn and winter respectively, other bacteria genus's proportion were less than bacillus. This was probably related to the basic proterties of soil, the alternation of four seasons, the change of temprature and the difference of vegetation were fairly suitable to the growth of bacillus . We did degrading omethoate experiment with the isoloated bacteria, the result showed, except few bacteria lost the ability to dagrada omethoate after being isolated and purified, they can not grow up in the basic culture medium which use omethoate as sole carbon sources, the other isoloated bacteria could grow up in the basic culture medium that use omethoate as sole carbon sources, namely they could degrada and use omethoate.