农药污染对水稻田土壤反硝化细菌种群数量及其活性的影响

在实验室条件下，研究了农药污染对水稻田土壤反硝化细菌(Denitrfying bacteria，DNB)种群数量及其反硝化活性的影响。结果表明，紫色稻田土壤、黄松稻田土壤和红壤稻田土的DNB种群数量范围分别为59．04×10⁴～157．59×10⁴、42．89×10⁴～108．97×10⁴和32．14×10⁴～75．30×10⁴cfu·g^-1，稻田土DNB种群数量和土壤NO3^-的消耗量之间具有正相关性。在1kg干土中加入1mg丁草胺或呋喃丹,能刺激DNB的生长及其反硝化活性,在1kg干土中加入5mg多菌灵、10mg丁草胺或呋喃丹，对DNB的生长及其反硝化活性有明显的抑制作用，丁草胺和呋喃丹施后7d，多菌灵施后14d，对水稻田土壤的DNB种群数量和反硝化活性抑制作用达到最大，然后逐渐减轻，最后呈现一定的促进作用。

Effects of pesticide-contamination on population size and denitrification activity of denitrifying bacteria in paddy soils

The effects of pesticide contamination on the population size and denitrification activity of denitrifying bacteria (DNB) were studied with three types of paddy soil (Huangsong paddy soil, red earth paddy soil and purple paddy soil) treated with carbofuran, carbendazim and butachlor for four weeks. The results showed that the population size of DNB in purple paddy soil, Huangsong paddy soil and red earth paddy soil varied in the range of 59.04 x 10(4)-157.59 x 10(4), 42.89 x 10(4)-108.97 x 10(4) and 32.14 x 10(4)-75.30 x 10(4) cfu.g-1 dried soil, respectively, which was positively related to the quantity of consumed nitrate in paddy soils. The population size and denitrification activity of DNB were increased by adding carbofuran (1 mg.kg-1 dried soil) or butachlor (1 mg.kg-1 dried soil), but decreased significantly by adding 10 mg.kg-1 dried soil of butachlor, 5 mg.kg-1 dried soil of carbofuran, and 10 mg.kg-1 dried soil of carbendazim on 7th d, 14th d and 7th d, respectively.