Heavy mechanization - a factor suppressing microbiological activity in the soil under soybean

Abstract

An investigation has been conducted on the effect of soil compaction on the number and enzymatic activity of soil microorganisms. The numbers of systematic and physiological groups of microorganisms and their dehydrogenase, protease and urease activities were found to depend on the degree of soil compaction, microorganism type, depth of soil profile and date of soil sampling. The number and enzymatic activity of microorganisms were higher in loose soil than in compacted soil regardless of sampling date and the depth of soil profile. Soil compaction tended to suppress the number and enzymatic activity of all aerobic microorganisms, while increasing the numbers of anaerobic bacteria and denitrifiers. Microbiological activity decreased with the depth of soil profile in compacted and loose soil alike. Microbiological activity was most intensive in the middle of growing season, and least intensive at the end of the season.