污灌对农田土壤微生物特性影响研究

Effects of sewage irrigation on quantity and distribution of microorganisms in soils

污灌对农田土壤特性和农作物生长有重要影响,通过分析污灌对农田土壤微生物特性影响,为农田污灌的实际应用和标准制定提供理论依据。分别采用平板计数法和最大可能数(Most-Probable-Number,MPN)法,研究了污水灌溉对农田土壤中普通微生物(细菌、放线菌、真菌)和功能微生物(亚硝化细菌、硝化细菌、氨氧化细菌、反硝化细菌、好气性自生固氮菌、好气性纤维素分解菌)的数量和分布特性的影响,并对不同类群微生物数量与土壤理化性状进行相关分析。结果表明:污灌减少农田土壤放线菌、真菌、亚硝化细菌、硝化细菌和反硝化细菌数量,增加细菌、氨氧化细菌和好气性纤维素分解菌的数量,其中细菌、好气性纤维素分解菌数量变化分别达显著水平(P<0.05),氨氧化细菌变化达极显著水平(P<0.01);污灌区大豆(Glycine max)、玉米(Zea mays)和水稻(Oryza sativa)根系土壤微生物数量分布差异很大,但都呈现真菌、好气性自生固氮菌和好气性纤维素分解菌数量变化显著的趋势(P<0.05);污灌土壤中微生物含量与土壤理化性状相关分析表明,细菌、反硝化细菌和好气性纤维素分解菌与有机质显著正相关(r=0.843,P<0.05;r=0.220,P<0.05;r=0.843,P<0.05),放线菌与全磷极显著负相关(r=-0.921,P<0.01),亚硝化细菌和好气性自生固氮菌数量与氨氮含量显著正相关(r=0.973,P<0.05;r=0.988,P<0.05),氨氧化细菌和反硝化细菌与有效磷含量显著负相关(r=-0.967,P<0.05;r=-0.988,P<0.05)。这说明污灌对农田土壤微生物和理化特性影响显著,对农作物会产生一定的影响。

Sewage irrigation has an important effect on farmland soil properties and crop growth. In order to provide theoretical basis for putting sewage irrigation into practical use, microorganisms characteristics in soils were studied. The plate counting method and most-probable-number （MPN） method were employed to research the effects of sewage irrigation on quantity and distribution of common microorganisms such as bacteria, actinomycetes and fungus and functional microorganisms such as nitrite bacteria （NOB）, nitrate bacteria （NB）, ammonia oxidizing bacteria （AOB）, denitrifying bacteria （DB）, aerobic nitrogens-fixing bacteria （ANB） and cellulose decomposing bacteria （CDB） in soils. And the correlation between microorganisms quantities and physical and chemical properties was also analyzed. The results indicated that the quantities of actinomycetes, fungus, nitrite bacteria, nitrate bacteria and denitrifying bacteria were reduced, but the quantities of bacteria, ammonia oxidizing bacteria and aerobic cellulose decomposing bacteria were increased significantly （p〈0.05） after sewage irrigation. There was a big difference among soil microorganisms quantities of soybean, corn and rice root system, but the quantities variation of fungus, aerobic nitrogens-fixing bacteria and cellulose decomposing bacteria of them were always significant（p〈0.05）. The correlation analysis showed that organic matter was positively correlated to bacteria （r = 0.843, p〈0.05） , denitrifying bacteria （r=0.220, p〈0.05） and cellulose decomposing bacteria （r=0.220, p〈0.05）, there was a significant negatively correlation between actinomycetes and total phosphorus（r=-0.921, p〈0.01）, ammonia nitrogen was positively correlated to nitrite bacteria （r = 0.973, p〈0.05） and aerobic nitrogens-fixing bacteria （r=0.988, p〈0.05）, available phosphorus was negatively correlated to ammonia oxidizing bacteria （r=-0.967, p〈0.05） and denitrifying bacteria （r=-0.988, p〈0.05）. The research showed that sewage irrigation had significant effects on microorganisms characteristics quantities and soil physical and chemical properties, and could have some effects on crop growth.