农药污染对水稻田土壤硫酸盐还原菌种群数量及其活性影响的研究

EFFECTS OF PESTICIDE-CONTAMINATION ON POPULATION AND ACTIVITY OF SULFATE-RED UCING BACTERIA IN PADDY RICE SOILS

在实验室条件下 ,施用杀虫剂 (呋喃丹 )、杀菌剂 (多菌灵 )和除草剂 (丁草胺 )后 ,对黄松稻田土壤、紫色稻田土壤和红壤稻田土的硫酸盐还原细菌 (Sulfate reducingbacteria ,SRB)种群数量和硫酸盐还原活性的影响。结果表明 ,紫色稻田土壤、黄松稻田土壤和红壤稻田土的SRB种群数量和硫酸盐还原活性的范围分别为 (66 83～ 12 7 81)× 10 4 cfug- 1干土、(45 87～ 10 5 0 7)× 10 4 cfug- 1干土和 (3 81～ 61 62 )× 10 4 cfug- 1干土和S- 2 (7 14～ 11 57) μgg- 1d- 1干土、S- 2 (6 84～ 9 0 7) μgg- 1d- 1干土、S- 2 (1 91～ 6 67) μgg- 1d- 1干土 ,且稻田土SRB种群数量和土壤硫酸盐还原活性之间具有正相关性。每kg干土中加入 1mg的丁草胺或呋喃丹 ,能促进SRB的生长及其硫酸盐还原活性。 1kg干土中加入 5mg的多菌灵、50mg的丁草胺或呋喃丹 ,对SRB的生长和硫酸盐还原活性有明显的抑制作用。施用丁草胺和呋喃丹 7d时 ,多菌灵 14d时 ,对水稻田土壤的SRB种群数量和硫酸盐还原活性的抑制影响最大 ,然后逐渐减轻 。

Effects of pesticide contamination on pop ulation and activity of sulfate reducing bacteria(SRB) were investigated in thr ee paddy soils, Huangsong paddy soil developed from shallow marine deposit of i ntermediate lake deposit, Red paddy soil developed from alluvial deposit and Pur ple paddy soil developed from parent material of neutral purple sandstone and sh ale, 4 weeks after the soils were applied with insecticide (carbofuran), fungici de (carbendazim) and herbicide (butachlor) at different concentrations. The resu lts showed that population and the sulfate reducing activity of SRB in Purple paddy soil, Huangsong paddy soil and Red paddy soil ranged (66.83～127.81)×10 4, (45.87～105.07)×10 4, (3.81～61.62)×10 4cells per gram dried soil, respec tively, and S -2 (7.14～11.57), (6.84～9.07), (1.91～6.67)μg d -1 g -1 dried soil, respectively, and that the sulfate reducing activity was pos itive relativity to the population of SRB in paddy soil. The population of SRB a nd the sulfate reducing activity were increased by addition of carbofuran (1 mg kg -1 dried soil) or butachlor (1 mg kg -1 dried soil) in paddy soils, but significantly inhi bited by addition of butachlor (50 mg kg -1 dried soil),carbofuran (5 mg k g -1 dried soil) and carbendazim (50 mg kg -1 dried soil) in paddy soil till 7 d, 14 d and 7 d, respectively. Then the inhibition effects of the contam inants were gradually attenuating. Eventually pesticide or metabolism of pestici de became contributive to the population of SRB and their sulfate reducing acti vity.