纳米TiO_2对土壤中自生固氮菌活性的影响

Effect of Nano-TiO_2 on Activity of Azotobacterin Soil

利用盆栽实验方法,考察砂土、黑土和泥炭土中纳米TiO_2对自生固氮菌活性的影响.结果表明:在不同类型土壤中纳米TiO_2对自生固氮菌活性均产生抑制作用,作用大小为砂土>黑土>泥炭土;在砂土和泥炭土中掺杂不同剂量(0.5,1.0,2.0g/kg)的纳米TiO_2,自生固氮菌的抑制率随添加剂量的增加而增大;砂土和泥炭土中添加2.0g/kg纳米TiO_2在第15天抑制率达到最大值,分别为25.73%和12.76%;3种土壤中种植紫花苜蓿后其根际作用和根系分泌物均可间接减少纳米TiO_2对自生固氮菌的抑制作用,且在黑土和泥炭土中种植组和未种植组差异极显著(P<0.01),在砂土中种植组和未种植组差异显著(P<0.05).

By potting experimental method,we studied effect of nano-TiO_2 on the activity of Azotobacterin sandy soil,black soil and peaty soil.The results show that nano-TiO_2 inhibit the activity of Azotobacterin different types of soil,and the order of inhibition is sandy soilblack soilpeaty soil.The inhibitory rate of Azotobacterincreases with the increase of the dosage of nano-TiO_2 at different doses（0.5,1.0,2.0g/kg）in sandy soil and peaty soil.2.0g/kg nano-TiO_2 are added to sandy soil and peaty soil,and the inhibition ratio reaches the maximum at the 15 th day,25.73% and12.76%respectively.After planting of alfalfa in three soils,the rhizosphere effect and root exudates can indirectly reduce the inhibitory effect of nano-TiO_2 on Azotobacter.The difference is extremely significant between the planted group and the unplanted group（P0.01）in the black soil and peaty soil,and the difference is significant between the planted group and the unplanted group（P0.05）in the sandy soil.