This was also the case of deeper la

This was also the case of deeper layers. At that, we can assume that nitrate N migrated beyond the root zone in 2016. In 2015–2016, nitrate-N in the 0–40 cm layer decreased during the flower-bud formation because plants took in some of it. In 2017, its content on the contrary increased due to higher temperature in July, which boosted current nitrification. Nitrification depends on soil temperature, and starts at 10 °C above zero, getting stronger until 39 °C, and stops at 43–45 °C. The optimum setting is 25–30 °C (Chernenok, 1997; Chernenok et al., 2017).