Effect of Nitrogen Fertilization and Microbial Preparations on Nmin Content in Soil after Potato Harvesting

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A three-year field experiment was conducted under conditions of Luvic Chernozem soil. Diversified nitrogen fertilization with 0, 60, 120, and 180 kg N ha-1, and microbial preparations improving soil properties were applied to potatoes, cv. ‘Satina’, cultivation. N–NO3 concentration in the soil profile (0–0.9 m) in autumn after potato harvesting fluctuated from 28 kg N ha-1 in the N0 treatment to 70 kg N ha-1 in the N180 treatment, whereas N–NH4 content varied from 22 to 48 kg N ha-1, respectively. The level of nitrogen fertilization also had a significant effect on the change in soil N–NO3 content during the autumn-winter period. The decrease in N–NO3 content in the N0 treatments was 7% compared to 24% in the N180 treatments. Application of microbial preparations to potato cultivation caused an increase in Nmin content in soil after crop harvesting. However, after the autumn-winter period, a lower amount of N–NO3, compared to the control treatment, was found in the treatments where microbial preparations had been used.