Microbial biomass and activity in a grassland soil amended with different application rates of silage effluent - a laboratory study

In this laboratory study, effluent-amended soils were incubated at 25°C for 32 days and periodically sampled. After 2 and 4 days of incubation, there was a significant trend of increasing microbial biomass C, microbial respiration (CO2 evolution), and dehydrogenase activity with increasing rates of silage effluent application. Thereafter, microbial biomass C, microbial respiration and dehydrogenase activity declined. In a second experiment, there was a significant positive linear relationship between increasing rates of silage effluent application up to 30 l m2 and microbial respiration. Dehydrogenase activity increased up to an equivalent application of 15 l m2 and then declined. -from Authors