Journal of Pure and Applied MicrobiologyVol. 8 No. May 2014 Special Edition

How do Earthworms in Soil Respond to Nitrification Inhibitor? - An investigation from A Microbial Aspect

Zhenyu Wang1,2, Weichao Yang1, Tao Kong1,2, Hao Sun1,2, Song Hu1 and Hui Xu1*

1Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China. 2University of Chinese Academy of Sciences, Beijing 100049, China.

Received on 12 April 2014 and accepted on 09 May 2014

 

ABSTRACT

A laboratorial incubation experiment was conducted to test the response of earthworm (Eisenia fetida)-related microbes to the application of dicyandiamide (DCD), a nitrification inhibitor. The potential of ammonium oxidation in soil was inhibited during the 90 days cultivation. At day 90, it was observed the soil surface was drilled more severely by earthworms in DCD treatment than E treatment. Meanwhile, comparedwith E treatment, the results of soil community level physiological profiles indicated that the potential of carboxylic acids and carbohydrates utilization in soil was enhanced by DCD addition.The active microbial biomass was increased by 43% andthe polyphenol oxidase activity was enhanced by 14% in DCD treated soil than control. More importantly, the number of denitrifying bacteria in earthworm gut content at day 90 was markedlydeclined from 1.79?1010g [fresh wt]-1 in control to less than 1?106 g [fresh wt]-1in DCD treatment.These results implied that DCD application was anabiotic selection pressureon the activities of earthworms and themicrobes both in soil and in earthworm, which might led to a shift of interaction between earthworms and the microbes.

Keywords : Earthworm; DCD; Microbe, soil quality.