The influence of mineral fertilizers on the content of easily hydrolyzed nitrogen and nitrification capacity of arable chernozem in the forest-steppe of Trans-Urals

Nitrogen reserves in the soil and its nitrification capacity are objective indicators of soil fertility. The effect of increasing doses of mineral fertilizers on the content of easily hydrolyzed nitrogen of leached arable сhernozem was studied. The research to identify the effect of fertilizers on the nitrification capacity of arable land was conducted. In the course of research, the content of easily hydrolyzed nitrogen in arable chernozem was determined on control (without fertilizers) and with increasing doses of mineral fertilizers. It was found that natural and minimal agricultural background (NP per 3 t/hectare of grain) in 0-40 cm layer had had low availability of easily hydrolyzed nitrogen. Systematic application of mineral fertilizers to the planned yields of 5 and 6 t/hectare of grain contributed to its significant increase relative to the control. At the maximum agrophone (NP 6 t/hectare of grain) in the layer of 20-40 cm, the content of easily hydrolyzed nitrogen was significantly lower due to active work of mineralizing microflora. In the course of work, the correlation coefficient between the yield and the content of easily hydrolyzed nitrogen in the soil was determined, which made 0.8 units and it showed that these factors were closely related to each other. The results of long-term research showed that there had not been any noticeable changes in the nitrification activity of old-arable chernozem both on the variant without fertilizers and when applying low doses of mineral fertilizers. Nitrification was 12.0 and 13.3 mg/kg of soil, respectively. The application of mineral fertilizers to the planned grain yield of more than 5 t/hectare, nitrification increased by 1.5 times relative to the control. A close relationship between easily hydrolyzed nitrogen and the nitrification capacity of the soil was established, the correlation coefficient made 0.94 units.