Abstract

Inoculation is the best way to ensure good nodulation with the proper strain of nitrogen-fixing bacteria for increased yield in an environmentally safe manner. This investigation was conducted on three-year experiment which was set up in four replications with three-crop rotation (maize-soybean-wheat) at experimental field of the Institute of Field and Vegetable Crops, Novi Sad, Serbia. Effects of application of microbiological fertilizer (with nitrogen-fixing bacteria Bradyrhizobium japonicum) on root mass, number and mass of nodes per plant, soil biogeneity (number of ammonifiers, Azotobacter, actinomycetes), as well as the effect on soybean yield were studied. Obtained results indicated positive impact of inoculation on nitrogen fixation parameters. The higher amounts of mineral nitrogen had negative impact on atmospheric nitrogen fixation, i.e. by increasing preplanting mineral nitrogen amount in the soil by 1 kg, the amount of calculated nitrogen from the air was decreased by 1.72 kg. Increasing abundance of studied microorganisms in the rhizosphere, as well as soybean yield using microbiological fertilizer was stimulated by plowing under crop residues. The impact of meteorogical conditions on the effects of inoclutaion was very significant.

Key words: Inoculation, fertilizing, nitrogen fixation, soybean, microorganisms, yield.