The effectiveness of N-fertilization and microbial preparation on spring wheat

The efficiency of the application of microbial preparations enhancing soil properties as well as the diversified fer tilization of spring wheat nitrogen was evaluated in the field experiment. Factors of the experiment referred to the levels of nitrogen fertilization: 0, 40, 80, 120 and 160 kg/ha as well as the application of microbial preparations, namely, Proplantan (disaccharide, and polysaccharide, lactic acid, carotene, riboflavin, thiamine, amylase, sea salt, minerals), Effective microorganisms (milk bacteria, photosynthetic bacteria, yeast, actinomycetes, moulds) and UG max microorganisms (lactic acid bacteria, photosynthetic bacteria, nitrogen-fixing bacteria, actinomycetes, macro- and microelements). The quantity of N min in the soil layer of 0–0.9 m ranged in respective years from 72.8 to 98.5 kg/ha before the spring wheat seeding and from 58.6.8 to 68.2 kg/ha after the crop was harvested, whereas the amount of N mineralization ranged from 18.9 to 53.3 kg/ha. Grain yields of wheat developed at a high level from 3.26 to 8.31 t/ha. To create the biomass, spring wheat plants absorbed nitrogen ranging from 78 kg N/ha in objects not fertilized to 184 kg N/ha in objects fertilized with the dose of 160 kg N/ha, and the share of nitrogen accumulated in the seeds amounted on average to 82% of the total uptake of that element. The highest N use efficiency, N physiological efficiency, N agronomic efficiency and N apparent recovery fraction were detected in objects fertilized with the dose of 40 kg N/ha. Each increase in the level of nitrogen fertilization affected lowering of the values of evaluated fertilization efficiency ratios.