Effect of Nano-Silver Application On the Soil Biological Activity In Agricultural Field.

Nano silver has been utilized in agricultural field as herbicide and pesticide because of biocide effect. However, limited information is available regarding the effect of nano silver on soil activity especially biological aspect after its application in the field. For this reason, impact of nano silver application on soil activity was evaluated by examining biological parameters of soil such as soil respiration, microbial biomass C, N, P, and soil enzyme concentration. Soil respiration was rapidly decreased at the first week of experiment for all the examined concentration (15, 30, 60 mg kg^-1) and higher inhibition rate of microorganism was observed from 30 mg/kg of nano silver in soil. Similar result was observed for microbial biomass C, N, P showing rapid decreasing at the first week of experiment and gradually decreasing afterward. In terms of soil enzyme concentration, inhibition rate of dehydrogenase (4-87%) was higher than urease (2-31%) depending on soil texture and nano silver concentration in soil. Among 3 different soil texture, loamy soil (25-87%) showed the highest inhibition rate for dehydrogenase and generally higher inhibition rate was observed as high concentration of nano silver was spiked in soil. The result of correlation analysis showed that concentration of urease was positively correlated with microbial biomass N while negatively correlated with microbial biomass C and P. In case of dehydrogenase, opposite result was observed compared to urease. In conclusion, nano silver application in agricultural field can affect biological parameters in soil and further research is necessary to establish proper guideline of nano silver usage in agricultural practice.