关键词: 农药, 呋喃丹, 阿特拉津, 土壤, 潮土, 水稻土, 土壤大孔隙, 淋溶

Abstract: Leaching of carbofuran and atrazine in soil columns of fluvo-aquic soil from Henan and two types of paddy soils from the Taihu Lake Region and its affecting factors were studied.Results show that leaching speeds of the two pesticides were lower in Henan fluvo-aquic soil than in Taihu paddy soils.When 2 mg of the pesticides was added separately in the surface soil,a 200 mm simulated shower brought the peak value of carbofuran down to 25-30 cm in depth and that of atrazine to 15-20 cm in depth,suggesting that the two pesticides show strong leachability in the soil columns.Soil and pesticide properties were main factors affecting leachability of the pesticides.The higher the contents of soil organic matter and clay particles,the stronger the pesticides adsorbed by the soil,the less likely the pesticides get leached with water;and the more the soil macropores,the more leachable the pesticides in the soil columns.Moreover,synergy was observed between adjacent macropores.The contents of the pesticides in the leachates from the soil columns inserted with 4 straight porous glass tubes were 2.7 times as much as those from the soil columns inserted with only 2 straight glass tubes,and 10 times as much as those from the soil columns without glass tubes.When straight glass tubes were replaced by tortuose(60°) glass tubes,more pesticides remained in the soil column due to weakened leachability.The higher the solubility of the pesticide,the more leachable in the same soil column.

Key words: pesticide, carbofuran, atrazine, soil, fluvo-aquic soil, paddy soil, soil macropore, leaching