The 30 years old long-term experiment of Látókép is continued in our experiments. The long-term fertilization experiment was set in 1983, and our sample was taken in spring 2014. The examinations of soil respiration processes and factors that influence soil respiration are required in optimal management. In our study, we interested to know how the growing levels of fertilization influence the microbial processes under nonirrigated and irrigated conditions in maize mono, bi, and triculture. The experimental results and those statistics suggest that the bi and triculture influenced higher microbial activity which was reflected in number of fungus, soil respiration, and microbial biomass carbon (MBC).