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

A three-year field experiment was conducted under conditions of Luvic Chernozem soil. Diversified nitrogen fertilization with ۰, ۶۰, ۱۲۰, and ۱۸۰ kg N ha-۱, and microbial preparations improving soil properties were applied to potatoes, cv. ‘Satina’, cultivation. N–NO۳ concentration in the soil profile (۰–۰.۹ m) in autumn after potato harvesting fluctuated from ۲۸ kg N ha-۱ in the N۰ treatment to ۷۰ kg N ha-۱ in the N۱۸۰ treatment, whereas N–NH۴ content varied from ۲۲ to ۴۸ kg N ha-۱, respectively. The level of nitrogen fertilization also had a significant effect on the change in soil N–NO۳ content during the autumn-winter period. The decrease in N–NO۳ content in the N۰ treatments was ۷% compared to ۲۴% in the N۱۸۰ 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–NO۳, compared to the control treatment, was found in the treatments where microbial preparations had been used.